TM 5-3805-254-14P-2 PART 7 IHC F-5070 DUMP TRUCK

8/14/2019 TM 5-3805-254-14P-2 PART 7 IHC F-5070 DUMP TRUCK

1/94

TRUCK SERVICE MANUAL STEERING

9. Make reference marks on cylinder head, bearingcap and gear housing for reassembly purposes.

10. Remove cylinder head and gasket, Fig. 12.11. Remove bolts from the bearing cap, then turn the

actuating shaft and bearing cap out of theactuating valve, Fig. 13.

Fig. 13NOTE: Some bearing caps may incorporate a seal andseal retainer to prevent the entry o f dirt at the input endof earn Fig 14.

Fig. 1412. Remove lock pin from the bearing retaining nut,

Fig. 15.13. Use a spanner wrench, SE-2279, to loosen the

bearing retainer nut; then remove nut, Fig. 16.14. Press actuating shaft from the bearing cap, Fig.

17. Do not dismantle the actuating shaft, as it isonly furnished as an assembly.

Fig. 15

Fig. 16

Fig. 17[5. Pry dirt seal from the, bearing cap, Fig. 18.

Fig. 18

639


2/94


16. Remove oil seal from bearing cap using ahammer and drift punch, Fig. 19.

Fig. 1917. Pull piston assembly from gear housing, Fig. 20.

Fig. 20

Fig. 2 1

18. Make reference marks on piston and adjustmennut. Then remove locking pin from valvadjusting nut, Fig. 21.

19. Remove valve adjustment nut from piston, Fig22.

Fig. 2220. Lift reversing spring from the actuating valve

Fig. 23.

Fig. 23

640


3/94


Fig. 2421. Pull actuating valve from the piston. Do not force

valve from the piston assembly, Fig. 24.22. Remove valve positioning pin from the piston

using a screwdriver, Fig. 25.

Fig. 25

23. Remove remaining reversing spring from thpiston.

24. Remove piston rings from piston.

Fig. 2625. Remove valve seats using a 3/16" Allen wrench

Fig. 26. NOTE: Do not lose relief valve ballswhich are spring loaded. The relief valve sprincan then be removed.

26. Remove seal (quad ring) from output shaft boreFig. 27.

27. If bushings in the housing or cover neereplacing, they may be removed using a puller.

Fig. 27

641


4/94


CLEANING, INSPECTION AND REPAIR

Cleanliness is of utmost importance. Use cleansolvent to wash grease, oil or dirt from all metal parts.Clean machined parts individually to avoid damage dueto "bumping" togPther of parts. Use lint-free clothsdipped in a clean solvent to clean all machined surfaces.After all parts are cleaned, dry parts with compressed air.

A careful visual inspection of the steering gearparts is very important. Inspect components for burrs ornicks, especially on or near the rack (teeth) on the piston.

If a raised burr is found on the piston, it shouldbe removed with a fine hand stone. All 0rings, seals andgaskets should be replaced Inspect the output shaftbushings for wear.

REASSEMBLY1. Install new bushings (if removed) in the gear

housing and cover, using a press and a straightline pushing action. The bushing is pushed intothe gear housing, so that the inside face ofbushing is flush with inside face of gear housing,Fig. 23.

When a new bushing is pressed into the cover,the face of the bushing must be flush with the cover, Fig.24. When reinstalling bushing in output shaft bore ofhousing, if it goes in easily and heavy press resistance is

not encountered, carefully remove bushing. Thoroughlyclean bushing of oil and grease and clean bore of foreignmaterial by scraping with a piece of brass sheet. Bushingand bore should then be completely washed and dried.Coat exterior of bore and bushing with Loc-tite highstrength retainer compound. Reinstall bushing and allowa minimum of six hours curing time. When the curingtime has elapsed, any excess Loc-tite in quad ringgroove or elsewhere should be -removed by washingwith naphtha.

2. Install a new quad ring in the groove in the gearhousing.

Fig. 28

Fig. 29

3. Position the relief valve spring and one relievalve ball into the valve bore. Then using a 3/16Allen wrench, install one of the valve seats. Thevalve seats must be tight and flush with oslightly below the end surface of the piston.

4. Install the second relief valve ball seat in thsame manner.

5. Position one of the reversing springs in bottom ovalve bore. Be sure spring is centered. The end

of the valve must enter the inside diameter of thspring.

6. Install the valve positioning pin in the piston. Turpin inward with a screwdriver until it is below theoutside surface of the piston. The flats mustenter into the piston 1/4" to engage the matingslot in the valve.

642


5/94

STEERING TRUCK SERVICE MANUAL

7. Carefully slide the actuating valve into the pistonso that the slot on the end of the valve ispositioned over the pin.

8. Position the remaining reversing spring on

shoulder of the valve end.

9. Reinstall valve adjusting nut, turning it clockwiseinto the piston until it is against the spring. Alignthe reference marks on the nut and piston. Thenlock nut in place by installing the locking pin. Besure pin is below the outside edge of piston.

10. Install piston rings. NOTE: If piston rings aretapered on one side, install the taper outward to thepiston end. if rings are marked "top" on one side, alsoassemble these rings with the marked side outward tothe piston end. Rings which are neither marked nor

tapered are not required to be installed on the piston inany special manner.

11. Install piston assembly using a ring compressoron each end. Fig. 30 illustrates ring compressor onsecond ring. Be sure piston is installed with theactuating shaft opening facing the bearing cap end.NOTE: Before installing piston, coat piston and cylinderwalls with oil.

Fig . 30

Fig . 31

Fig . 32

12. Using a new gasket reinstall the cylinder head.The alignment marks will aid in reinstalling thehead in the correct position. The opening for theplunger must be in alignment with relief valve inthe piston. Check torque chart for bolt tightening

643


6/94


13. Press a new oil seal and dirt seal into bearingcap, Figs. 31 and 32.

Lubricate surface between seals beforeinstalling actuating shaft assembly.

(Use Ball Bearing Lubricant.)

14. Press actuating shaft assembly into the bearingcap, Fig. 33.

Fig . 33

15. Install bearing retaining nut. Insert locking pinthrough the hole in bearing cap and into thehole in nut. If a new nut is being used, drill a3/32" hole in nut. The nut must be in place todrill this hole. Drill through the locking pin holein the bearing cap and 3/16" into the nut.

16. Using a new gasket on the bearing cap threadactuating shaft into the valve. Line up punchmarks on gear housing and bearing cap. Turnshaft until cap comes into place on the end ofcylinder. Check plunger hole alignment withvalve seat in the piston. Tighten bolts to

specified torque.

17. Align the timing mark on output shaft gear withmarked spline on the output shaft andreassemble. Use a press if necessary, Fig. 34.

Fig . 34

18 Insert output shaft in gear housing aligning markon the center tooth on the pinion with mark onthe output shaft. NOTE: Be very careful so thathe gear tooth and rack tooth are properlyaligned. If a tooth on the pinion strikes theground outside diameter surface of the piston, aburr will be raised which will score the cylindewall. This burr should be removed with a finehand stone before further assembly.

19. Install the gear retaining nut. The nut must betight against the output shaft gear. Thecapscrews are then installed in the retaining nutIf the holes do not line up with the gear, back thenut off until they do. Tighten the capscrews withan Allen wrench.

644


7/94


NOTE: On late production seriessteering gears install a new retaining pinto proper depth and replace roll pin.

20. Position a new 0ring seal on housing cover.Install cover assembly. It may be necessary touse a soft hammer to tap the cover in place.

21. Install the bolts and torque to properspecifications.

22. The relief valve plungers with the jam nuts maynow be installed using new O-rings. Turn themapproximately six turns. Final adjustment of theplungers is made when the steering gear isinstalled on the vehicle.

FINAL ADJUSTMENTS

Bleeding Air from System

After reinstalling the steering gear on the vehicle

but prior to installing the pitman arm, bleed the air fromsteering system in the following manner:1. Fill pump reservoir with SAE-10W-30 engine oil.

It will be necessary to continue filling afterstarting the engine and during the bleedingoperation until correct oil level is maintained.

2. Set parking brake or block wheels. Start engineand allow it to operate at fast idle speed.

3. With engine running turn steering wheel from leftto right and return, making three complete cyclesto remove all air from the steering system.

4. Stop engine.

PITMAN ARM INSTALLATION

NOTE: To provide proper alignment ofthe pitman arm to the output shaft, anarrow is stamped on the arm and a dot(or indentation) is on the output shaftend. These marks must always be inalignment when the pitman arm isinstalled on the output shaft.

There are two methods of retaining the pitmanarm on the output shaft:

1. Two setscrews are threaded into the pitman arm

and are tightened into a "V" type groove in theoutput shaft. Setscrews are either equipped witha Nylock insert or jam nut to secure setscrews inplace, Fig. 35.

Fig . 35With this method of retaining the pitman arm on theoutput shaft, two procedures are used when installing thearm.

If the output shaft is equipped with a 1/2" x 20ONF or9/16" x 18NF hole, a bolt approximately 4-1/4" long, an

adapter (large socket) and flat washer can be assembledas shown in Fig. 36. Tighten the bolt to force the pitmanarm on the shaft. After the 1/2" bolt is tightened to 85 ftlbs. or 9/16" bolt is torqued to 125 ft. lbs., the twosetscrews are tightened to 15 ft. lbs. and then the jamnut tightened. The 1/2" bolt, adapter and washer arethen removed.

If the end of the output shaft is not equipped with either a1/2" or 9/16" threaded hole, the pitman arm should beforced on the output shaft with a hammer.

The setscrews are then tightened to 12 ft. lbs. If jam

nuts are used, tighten them now.

Fig. 36

NOTE: In either case the shaft may berecessed or protruding 3/64" maximumfrom outer face of pitman arm.

645


8/94

TRUCK SERVICE MANUAL STEERING]

2. The second method of securing the pitman armon the output shaft is with a large self-lockingnut, which is threaded onto the end of the outputshaft and tightened to specified torque to forcethe pitman arm in place, Fig. 37.

Fig. 37

ADJUSTING RELIEF VALVE PLUNGERS(Adjustable Stops)

1. Turn bearing cap plunger and the cylinder headplunger into the gear until they bottom.

2. Start the engine and allow it to operate at fastidle speed.

3. With full weight of the vehicle on all wheels, turnthe steering wheel until the bearing cap plungeropens the relief valve. Do not force the steering

wheel. You can feel the valve open as theturning effort is increased. Adjust the bearingcap plunger outward and continue to turn thesteering wheel until about 1/8" clearance ismaintained at the wheel stops. Do not changethe wheel stop adjustment. Lock the plungerwith jam nut. The same procedure is repeatedfor the cylinder head plunger.

4. The vehicle is now ready for road testing.

LUBRICATION

Keep the power steering pump reservoir filled toindicator level with SAE10W-30 engine oil.

When filling, start the engine. With enginerunning, turn steering wheel from left to right andcontinue filling until proper level is maintained.

A replaceable type filter element is located in thepump reservoir. Every 20, 000 miles or 600 hoursremove the reservoir cover and filter element. Cleaninside of reservoir with a lint-free cloth. Install a new filteelement and replace cover.

NOTE: Trucks operating in dusty areaswill require changing the filter elementmore often.

Filling the Hydraulic System

1. Fill reservoir to indicated level and replace cap.

2. Start engine and idle, turning wheels to the fuleft and right three times. Shut off engine and

refill reservoir to indicated level.

3. Continue operation in step "2" until systemmaintains its proper indicated oil level,

4. Run engine at faster speed and continue turningwheels slowly from full left to full right and backagain for approximately five minutes to check foleaks. This will bleed the system of air. Againrefill the reservoir to the indicated level or to 11/2" below top of filler neck on reservoir without

dipstick attached to filler cap.

NOTE: THE ABOVE INSTRUCTIONSARE IMPORTANT.

646


9/94


Fig . 38

647


10/94


Fig . 39

648


11/94


Fig . 42 Exploded View of Steering Gear (Dual System)(For symbol designation, see Parts Catalog . )

Legend for Fig . 42

Key Description1 ARM, Steering Right, Assembly2 HEAD, Right Cylinder3 SCREW, Steering Arm Set4 HOUSING with BUSHING, Gear5 BALL, Relief Valve6 SEAT, Relief Valve Ball7 RING, Piston

8 GASKET, Cylinder Head9 RING, Quad10 BUSHING, Housing Inner11 SHAFT, Output Gear12 GEAR, Output Shaft13 BOLT, Hex Socket Head 1/4NF x 5/814 NUT, Output Shaft Mounting15 BUSHING, Housing Outer16 O-RING, Gear Shaft

Key Description17 COVER, Right Gear Housing Mounting18 SPRING, Relief Valve19 WASHER, Piston Valve20 PIN, Valve Locking, 3/32 x 221 PIN, Valve PositioningZ2 O-RING, Plunger Valve23 PLUNGER, Relief Valve

24 NUT, Hex, 3/8NF25 SEAL, Housing Cover Outer26 COVER, with BEARING, Housing27 ARM, Steering Left, Assembly28 HEAD, Left Cylinder29 COVER, Left Gear Housing Mounting30 SEAL, Housing Cover Inner31 NUT, Bearing Retaining

649


12/94


TROUBLE SHOOTING

Power Steering Trouble Shooting

A thorough and orderly trouble shooting

procedure will help you diagnose power steering troublesquickly.

Troubles occur and show up in various ways; butwith the trouble shooting chart you can eliminate manypossibilities quickly, narrow down the cause of trouble,then make the correct repairs promptly.

Trouble shooting procedure should be followedin a three step organized manner:

1. Define the complaint.2. External inspection.

3. Hydraulic system check.

Cause of Bad Steering Outside of SteeringSystem

1. Soft tires.

2. Loose king pins.

3. Low pressure in one or more tires, particularlyrear tires.

4. Swinging load.

5. Improper fifth wheel location.

6. Sheared off spring leaf bolt on steeringgear side of truck.

7. Improper front end alignment (caster,

camber and toe- in).

TROUBLE SHOOTING CHART

PROBLEM POSSIBLE CAUSE REMEDY

1. Oil forcing out of filler capvent hole in reservoir.r

a. Dirty cartridge in reservoir.

b. Loose belts.

c. Air in system.

d. Malfunctioning pump.

Change oil and cartridge. Replace filtercartridge at short interval if necessary toclean up system

Tighten belts.

Bleed system and check adjustable stops.

Refer to pump servicing instructions.

2. Oil leakage at pump pulleyshaft

Worn oil seal Replace oil seal (change oil and filter,cartridge at more frequent intervals).

3. Oil leakage between reservoirand pump.

Overheating or age.. Replace O-ring between reservoir andpump.

4. Oil leaking at actuating shaftof steering gear.

a. Worn or damaged oil seal.

b. Worn or damaged actuatingshaft.

Replace oil seal.

Replace with actuating shaft assembly.

5. Oil leaking at output shaft ofsteering gear.

a. Worn or damaged output shaft.

b. Restricted oil return line.

c. Clogged filter.

d. Worn or damaged quad ring.

e. Worn cover bushing and/oroutput shaft bushing

Replace output shaft.

Check for obstructions and sharp bends inline.

Change oil and cartridge. Replace filtercartridge at shorter intervals.

Replace quad ring.

Replace bushings.

650


13/94



6. Excessive pump pressure-with steering gear in neutralposition

Kink in oil return line Relocate line to remove kink.

7. Erratic steering or no steeringat all

a. Insufficient volume of oil beingmetered by flow divider to steeringgear induced by foreign particles onflow divider valve, causing the valveto hang up in the bore.b. Flow divider spring takespermanent set because of fatigue,thereby allowing flow divider valveto move easily and reduce oilvolume.

c. Broken bypass spring in flowdivider.

Polish flow divider valve to removeforeign particles and burrs. Refer topump servicing instructions.

Replace flow divider spring. Refer topump servicing instructions.

Replace with flow divider valve assembly,which includes bypass spring. Refer topump servicing instructions.

8. Side motion in steering wheel. Broken jacket bearing in steering

column.

Replace jacket bearing.

9. Excessive backlash a. Worn universal joint.

b. Worn pins and keys, universaljoint to actuating shaft and universaljoint to steering shaft..

c. Low oil volume.

d. Pitman arm ball worneggshaped.

e. Improperly adjusted drag link,pitman arm to drag link and steeringarm to drag link.

f. Loose bracket, frame to bracketor bracket to gear

g. Worn or damaged actuatingvalve.

h. Rack or piston worn ordamaged.

i. Worn or damaged pinion gear onoutput shaft.

Replace universal joint

Replace pins and keys

Check flow divider and pump speedbelt(s).

Replace pitman arm assembly whereriveted or ball only where bolted ball isused.

Adjust drag link, drag link to pitman armand drag link to steering arm.

Remove bracket, clean frame andbracket; check radius of frame makingsure bracket is not bearing on radiussurface; check bracket for wear fromworking. Replace bracket and tighten torecommended torque rating according tosize and grade of bolts. If necessary,replace bracket with new one.

Replace with actuating piston and valveassembly.

Replace with actuating piston and valveassembly

Replace pinion gear.

651


14/94



10. Wheel steering hard in onedirection

Broken reversing springs in steeringgear.

Replaces reversing springs

11. Wheel steering hard in one or bothdirections.

a. Metal or foreign material caught inactuating valve. Actuating valve wornor chipped by dirt.

b. Bent or damaged king pins and tierods.

c. Front end load too great for ratedaxle capacity.

d. Fatigued bypass valve spring inpump.

Remove actuating valve, clean andcheck parts for damage. If damage isexcessive, replace with actuatingpiston and valve assembly

Repair or replace king pins and tierods. Refer to servicing instructions.

Lighten load or install larger steeringgear.

Replace with flow control valveassembly. Refer to pump servicinginstructions.

12. Hard steering a. Loose belts.

b. Worn pulley(s) due to belt slippage.

c. Improper belt

d. Low oil level in steering system..

e. Air in system.

f. Caster and camber degree

incorrect.

Tighten or replace belts

Replace pulley(s) and belts (keep beltight).

Replace with IH replacement part.

Fill oil reservoir as required.See Lubrication.

Bleed system and check for cause oair.

Correct to Specifications.

652


15/94


TORQUE CHART

Application Size Ft. Lbs.

Cylinder Head and Bearing Cap 5/16 - 24NF 20

Cylinder Head and Bearing Cap 3/8 - 24NF 33

Steering Gear Cover (Mounted) 7/16 - 2ONF 53

Steering Gear Cover (Mounted) 1/2 - 20NF 83

Steering Gear Cover (Mounted) 9/16 - 18NF 122

Steering Gear Cover (Mounted) 5/8- 18NF 167

Steering Gear Cover (Mounted) 5/8 - 11NC 152

Steering Gear Cover (Standard) 7/16- 20NF 36

Steering Gear Cover (Standard) 1/2 - 20NF 56



Steering Gear Cover (Standard) 5/8 - 11 100

Pitman Arm Set Screws 5/16 - NC 12

Pitman Arm Retaining Nut 1-1/2 - NF 450

Pitman Arm Retaining Nut 1-3/4 - NF 500

653


16/94


STEERING COLUMN ASSEMBLY

INDEX

Subject Page

DESCRIPTION................................................................................................................................... 656

HORN OPERATION AND CIRCUIT .................................................................................................. 661

LUBRICATION ................................................................................................................................... 661

OPERATION ...................................................................................................................................... 656

STEERING COLUMN INSTALLATION.............................................................................................. 658

STEERING COLUMN REMOVAL...................................................................................................... 657

STEERING JACK TUBE BEARING REPLACEMENT....................................................................... 658

STEERING WHEEL ALIGNMENT ..................................................................................................... 660

STEERING WHEEL INSTALLATION ................................................................................................ 657

STEERING WHEEL REMOVAL ........................................................................................................ 656

TORQUE CHART............................................................................................................................... 662

UNIVERSAL JOINT REASSEMBLY .................................................................................................. 659

UNIVERSAL JOINT REPLACEMENT................................................................................................ 659

654


17/94


Fig . 1

655


18/94


Key Description Key Description

1. Button, Horn 19. Bearing, Jacket Tube Lower Assy.2. Contact Cup, Horn Button 20. Seat, Bearing3. Plate, Horn Button Contact 21. Spring, Jacket Tube Bearing4. Spring, Horn Button 22. Cap, Dust5. Nut, Steering Wheel Mtg. 23. Cover, Universal Joint6. Wheel, Steering Assy. 24. Bracket, Steering Column Mtg.7. Contact Ring, Horn Button 25. Brace, Steering Column8. Contact Roller w/Cable 26. *Yoke, Upper End9. Flange Steering Column w/Bearing 27. Universal Joint10. Nut, Lock 28. Fitting Lubrication 1/4 Straight11. Washer, Flat 29. Slip Yoke12. Bolt, Clamp 30. Seal, Slip Yoke13. Spacer, Bearing 31. Shaft, Steering Slip14. Seat, Bearing 32. Washer, Slip Yoke Seal15. Bearing, Jacket Tube Upper Assy. 33. Cap, Dust16. *Shaft, Steering 34. Yoke, Lower End17. Tube, Jacket 35. Universal Joint18. Bracket Cap, Steering Column 36. Yoke, Steering Gear End.

* Parts 16 and 26 welded together on late model chassis.

DESCRIPTION

The steering column assembly provides thevehicle operator control of the steering gear from insidevehicle cab. This manual covers the 21 mm (7/81")diameter shaft, double jointed column used in theTranstar 4200, 4300, and 5000 Paystar series.

The turn signal and in most cases the trailerbrake control is mounted to the steering column jacket

tube. The only internal accessory not having to dodirectly with control of the steering gear is the hornassembly.

OPERATION

A steering wheel is connected to the uppersteering shaft, which is held by two sets of ball bearingsin the steering column jacket tube. The steering shaft isconnected to the slip shaft by a universal joint. Thelower end of the slip shaft is connected to the steeringgear by a second universal joint. The universal jointsand slip shaft permit correct alignment and smoothrotation of the steering shaft to steering gear with no

binding of the shafts.

STEERING WHEEL REMOVAL

The steering wheel can be removed as follows:1. Remove the plastic horn button by turning

it 28.575 mm (1 1/8") in either direction. The horn buttonwill be released from the rubber retainers on the hornbutton base plate. The contact cup and spring shouldalso be removed at this time (Fig. 2).

Fig . 2 Plastic Horn Button Removal

2. Remove the horn button base plate by removingthree top screws and one "ground" screw.

656


19/94


3. Remove steering wheel nut.

4. Install SE-1821 puller, two drilled and tappedholes are provided in the steering wheel.Remove as shown in Fig. 3.

Fig . 3 Steering Wheel Removal Using Puller SE-1821

5. On the reverse side of the steering wheel hub isa horn button contact ring. This contact ringrides on a contact roller and provides a path toground for horn operation. The contact ring canbe removed by removing the (2) mountingscrews.

STEERING WHEEL INSTALLATION

1. Install horn button contact ring on reverse side

of the steering wheel hub with (2) screws.Lubricate contact ring with IH 251 HEP greaseor the equivalent NLGI #2 multi-purpose lithiumgrease.

2. Check contact roller for freedom of movementin housing (see Fig. 4). Make certain that thespring seat and bearing spacer is in place onthe steering shaft.

3. Mount steering wheel on serrated steering driveshaft. Align open serration on top of steeringwheel hub with blind serration on steering driveshaft.

4. Rock steering wheel back and forth, use a soft

face mallet to seat wheel on steering driveshaft.5. Install steering wheel nut on steering drive shaft

and torque, dry (Fig. 5).

6. Install horn button base plate with (3) tappingscrews. Install "grounding" screws.

Fig . 4 Checking Contact Roller for Freedom of

Movement

Fig. 5 Torque Steering Wheel Nut7. Place horn button spring on steering wheel nu

and contact cup on spring. Place horn button oncontact cup, press down and turn until the rubbekeepers on base plate hold the horn button inplace.

STEERING COLUMN REMOVAL

For most servicing procedures it will benecessary to remove the steering column. This can be

accomplished with the steering wheel in place oremoved. Steering column removal can be completedas follows:

1. Open hood.

2. Remove pinch bolt from yoke at end of steeringslip shaft. Separate the slip shaft from the yoke.

657


20/94


3. If the steering wheel is removed, it is necessaryto replace the steering wheel nut to prevent thesteering shaft from sliding out of the steering

jacket tube. See index for steering wheelremoval.

4. Remove turn signal control from steeringcolumn.5. Remove trailer brake control if mounted on

steering column.6. Disconnect horn wire at the connector.7. Remove the lower bracket cap, and cover over

universal joint from steering column, refer to Fig.6.

8. Remove upper bracket cap and lift steeringcolumn from cab. Be careful not to tear therubber boot, or break the steering tube locatingpin in steering column mounting bracket. Whenreinstalling steering column the locating pin mustalign with hole in steering jacket tube.

Fig . 6 Steering Column Removal

STEERING COLUMN INSTALLATION

To install the steering column, reverse removalprocedure. Refer to torque chart for correct torque.

STEERING JACKET TUBE BEARINGS REPLACE-MENT

The steering jacket tube bearings are ballbearings. The outer race of the bearing is long with a lipto properly locate it in the

steering jacket tube.

The replacement operation will require removal of thesteering wheel, turn signal control, and trailer hand brakeif mounted on steering column. It will not be necessary

to remove the entire steering column assemblyReplacement procedure for the steering jacket tubebearings follows:

1. Remove steering wheel. For procedure refer tosteering wheel removal in the index.

2. Remove steering column bracket caps and slidesteering jacket tube from steering drive shaftDo not break the steering jacket tube locating pinin the steering column mounting bracket.

3. Place steering jacket tube in a vise. Use coppejaw covers or insulate vise with a rag. Take care

not to deform the steering jacket tube byovertightening the vise.

4. Remove bearing using an inside puller SE-1746(Fig. 7)

Fig . 7 Remove Steering Jacket Tube Bearings UsingPuller SE-1746

5. Pack new bearings with IH 251 HEP grease othe equivalent NLGI #2 multipurpose lithiumgrease.

6. Install bearings in steering jacket tube. Becareful to start bearing straight and tap gently toavoid damage to the bearing or steering jackettube.

7. Slide steering jacket tube over steering driveshaft and align with locating pin in steeringcolumn mounting bracket. Replace bracket capsand cover over universal joints, torque to valueshown in chart.

8. Reinstall turn signal control, trailer hand brakecontrol, steering wheel, and connect horn wiring

658


21/94


UNIVERSAL JOINT REPLACEMENT

The universal joint at the steering gear may beremoved and serviced separately. To service the upperuniversal joint it is necessary to remove the steeringcolumn.

Once the shafts and universal joints areremoved from the vehicle the procedure for servicing theuniversal joint is as follows

NOTE: Be careful not to damagebearing surfaces.

1. Place universal joint in vise as shown in Fig. 8.Remove snap ring fitting in grooves of the spiderbearings which locate them on the inside of theyokes. To remove snap rings; place ascrewdriver against an end of the snap ring andpush.

Fig . 8 Snap Ring Removal

2. Place shaft assembly in vise with one yokeresting on the vise and the other yokesuspended with the bearing to be removedfacing down (refer to Fig. 9). Tap yoke besidebearing to be removed, bearing should walk outof the yoke.

3. If the bearing does not come completely out,clamp bearing in vise. Use copper jaw coverson vise. Strike the yoke with a soft hammer anddrive the yoke away from the bearing as shownin Fig. 10.

4. With the bearings removed, the spider can beeasily removed from the yoke.

Fig. 9 Bearing Removal, Yoke in Vise

Fig. 10 Bearing Removal (Bearing in Vise Use CopperJaw Covers on Vise)

UNIVERSAL JOINT REASSEMBLY1. Make certain parts are clean before assembly.

2. Rest yoke on hard surface. Tap one bearingpart way into yoke with a soft hammer (see Fig11).

NOTE: Be certain bearings are started

straight in yoke.

659


22/94


Fig . 11 Start Bearing by Tapping with a Soft Hammer

3. Insert spider through the opposite hole, withoutbearing, swing it into place and down into thepartially installed bearing.

4. Turn assembly over and tap the oppositebearing part way into the yoke. Be certain tostart bearing straight in yoke.

5. Place yoke in vise with bearings against jaws ofvise. Tighten vise slowly and the bearings will bepressed into the yoke as shown in Fig. 12.

Fig . 12 Pressing Bearing Into Yoke

6. After pressing bearing into yoke the spider maybe off center in yoke. This is desirable becauseit permits installation of snap

ring on the side with the most clearance.Refer to Fig. 13 and install snap ring.

Fig . 13 Snap Ring Installation

7. After the first snap ring is in place turn assemblyover. The bearing with snap ring installed shouldbe on the bottom. Rest yoke on vise and strikebearing which is on top, this will seat bothbearings. Snap rings should rest against insidemilled surface of yoke. Install remaining snapring.

8. Lubricate universal joint with IH 251 HEP greaseor equivalent NLGI #2 multi-purpose lithiumgrease.

STEERING WHEEL ALIGNMENT

Proper steering wheel-to-steering gear alignmenis designed into the steering assembly. Following are afew alignment points to check at assembly or whensteering wheel alignment is a problem.

1. The steering wheel has open serrations at thetop that align with blind or closed serration onsteering shaft. The location of blind serration ismarked with either a center punch mark or chisemark on the end of the steering shaft as shownin Fig. 14.

NOTE: Do not attempt to adjust

steering wheel to straight ahead positionby relocating steering wheel to adifferent serration.

2. Test drive vehicle on a straight and level (nocrown) section of road for at least one-quartermile. Determine if or how far off center thesteering wheel is when the vehicle is goingstraight.

660


23/94


Fig . 14 Steering Wheel Alignment

3. If steering wheel alignment is off return vehicle towork area for further adjustment. Stop vehiclewith front road wheels (not steering wheel)straight ahead as indicated by driving test.

4. Disconnect drag link at the steering arm (PitmanArm).

5. Manual Steering: Turn steering wheel untilmark on steering gear output shaft isperpendicular to the input shaft, and the input

shaft yoke pinch bolt is at the bottom of theshaft, as shown in Fig. 15.Power Steering: Turn steering wheel until markon steering gear output shaft is perpendicular tothe input shaft (Fig. 15). If the steering wheel isoff center remove yoke from steering gear inputshaft and reinstall on different serrations to alignsteering wheel.

6. With the road wheels straight ahead andsteering gear aligned properly, adjust drag linkso it can be connected to the steering arm(Pitman Arm) without altering alignment.Connect drag link to Pitman Arm.

7. Test drive vehicle to assure that properalignment has been accomplished and thatsteering is correct.

Fig . 15 Steering Gear Alignment

HORN OPERATION AND CIRCUIT

The horn will not operate with the ignition switchin the "OFF" position.

When the ignition switch is in the "ON" o"ACCESSORY" position, current is available at the hornrelay. To energize the relay and feed current to the horna path to ground must be available. The path to groundis completed through the horn button mechanism in thesteering column.

The current path from the horn relay is through aconnector and wire that enters the steering column

jacket tube, where a spring loaded contact roller rides onthe contact ring on the lower side of the steering wheehub. This contact ring is connected to the horn buttonbase plate by a long "ground" screw. When the plastichorn button is depressed, the metal contact cup makes aconnection from the base plate through the contact cupsupport spring, to the steering drive shaft where the pathto ground proceeds down the steering shaft through thesteering gear to the frame.

LUBRICATION

The steering drive shaft tube bearings and the

universal joints should be lubricated at assembly with IH251 HEP grease or equivalent NLGI #2 multi-purposelithium grease.

661


24/94


TORQUE CHART

Application Torque

Steering Wheel Mounting Nut 101-108 N-m (75-80 Ft.lbs.)

Steering Column Bracket Cap 34-38 N-m (25-28 Ft.lbs.)

Steering Yoke Pinch Bolts 47 N-m (35 Ft.lbs.) *

* Insert cotter pin or advance to next slot and insert and spread cotter pin.

662


25/94

TRUCK SERVICE MANUAL TRANSMISSION

Service

Manual

Allison Transmissions

AUTOMATIC MODELS

ALLISON HT 750CRD (A/N 6839074)

IH T 475 PART NO. 515677 C91

1 SEPTEMBER 1975

663


26/94


IMPORTANT SAFETY NOTICE

Proper service and repair is important to the safe, reliableoperation of all motor vehicles. The service proceduresrecommended by Detroit Diesel Allison and described in thisservice manual are effective methods for performing serviceoperations. Some of these service operations require the use oftools specially designed for the purpose. The special toolsshould be used when and as recommended.

It is important to note that some warnings against the use ofspecific service methods that can damage the vehicle or render itunsafe are stated in this service manual. It is also important tounderstand these warnings are not exhaustive. Detroit DieselAllison could not possibly know, evaluate and advise the service

trade of all conceivable ways in which service might be done orof the possible hazardous consequences of each way.Consequently, Detroit Diesel Allison has not undertaken any suchbroad evaluation. Accordingly, anyone who uses a serviceprocedure or tool which is not recommended by Detroit DieselAllison must first satisfy himself thoroughly that neither his safetynor vehicle safety will be jeopardized by the service method heselects.

664


27/94


TABLE OF CONTENTS

Paragraph Page Paragraph Page

Section 1. GENERAL INFORMATION

1-1 SCOPE OF MANUAL ....... 672

1-2 SUPPLEMENTARYINFORMATION ................ 672

1-3 ORDERING PARTS ......... 672

1-4 GENERAL DESCRIPTION 672

1-5 OPERATING INSTRUCTIONS 674

1-6 SPECIFICATIONS, DATA675(chart)............................... 676

Section 2. DESCRIPTION AND OPERATION

2-1 SCOPE OF SECTION 2... 679

2-3 MOUNTING...................... 679

2-4 INPUT DRIVE................... 679

2-5 TORQUE CONVERTER .. 679

2-6 LOCKUP CLUTCH........... 680

2-7 TORQUE CONVERTERHOUSING......................... 680

2-9 OIL PUMP ASSEMBLY.... 680

2-10 FORWARD SUPPORT ANDVALUE ASSEMBLY.......... 681

2-11 FORWQARD CLUTCH ANDTURBINE SHAFT............. 681

2-12 FOURTH CLUTCH........... 682

2-13 SECOND, THIRD CLUTCHES,AND CENTER SUPPPORT 682

2-14 FIRST CLUTCH............... 683

2-15 LOW CLUTCH ................. 683

2-17 PLANETARY GEARING.. 684

2-19 SPEEDOMETER DRIVE . 685

2-20 GOVERNOR.................... 685

2-21 CONTROL VALVE

ASSEMBLY...................... 685

2-22 LOW SHIFT AND TRIMMERVALVES........................... 685

2-24 OIL PAN AND OIL FILTER 685

2-25 REAR COVER ................. 686

665


28/94


Section 2. Continued

Paragraph Page

2-26 HYDRAULIC SYSTEMa System Functions.......... 686b System Schematics....... 686c Oil Filter, Pump Circuit .t 686d Main-Pressure Circuit.... 686e Converter, Cooler,

Lubrication Circuit ... 686f Selector Valve, Forward

Regulator Circuit ..... 687g Rear Governor Circuit ... 687h Modulator Pressure

Circuit...................... 687i Trimmer Regulator Valve 688

j Trimmer Valves ............. 688

k Lockup Circuit (front governor) 688m Priority Valve ................. 689

Paragraph Pageo Clutch Circuits, Drive Ranges 689

q Automatic Upshifts........ 690r Automatic Downshifts ... 691

sDownshift and Reverse Inhibiting 691

2-28 TORQUE PATHS THROUGHTRANSMISSION....... 692

Section 3. PREVENT MAINTENANCE


3-2 INSPECTION AND CARE 699

3-3 CHECKING OIL LEVEL.... 699

3-4 KEEP OIL CLEAN............ 700

3-5 OIL SPECIFICATIONS..... 700

3-6 OIL AND OIL FILTERCHANGE INTERVALS ..... 700

3-7 OIL AND OIL FILTERCHANGE PROCEDURES 700

3-8 OIL CONTAMINATION .... 701

3-9 BREATHER...................... 702

3-10 LINKAGE.......................... 702

3-11 SHIFT SPEED ADJUSTMENT 702

3-12 EXTERNAL LINES, OILCOOLER .......................... 704

3.13 TRANSMISSION STALL TEST 704

3-14 PRESERVATION,STORAGE ....................... 706

3-15 CHECIING OIL PRESSURES 708

3-16 TROUBLESHOOTING -BEFORE REMOVAL OROPERATION.................... 708

3-17 TROUBLESHOOTING -BEFORE REMOVAL,DURING OPERATION .... 708

3-18 TROUBLESHOOTING -AFTER REMOVAL FROMVEHICLE.......................... 708

3-19 TROUBLESHOOTING708(chart)............................... 711

666


29/94



Section 4. GENERAL OVERHAUL INFORMATION

4-1 SCOPE OF SECTION 4...... 715

4-2 TOOLS, EQUIPMENT......... 715

4-3 REPLACEMENT PARTS..... 715

4-4 CAREFUL HANDLING........ 720

4-5 CLEANING, INSPECTION .. 729

4-6 REMOVING (OR INSTALLING) 722TRANSMISSION

4-7 WEAR LIMITS ................. 723

4-8 SPRING SPECIFICATIONS 723

4-9 TORQUE SPECIFICATIONS 723(chart)......................... 723

Section 5. DISASSEMBLY OF TRANSMISSION INTO SUBASSEMBLIES


5-2 REMOVING EXTERNALCOMPONENTS ......... 724

5-3 REMOVING FLYWHEEL,LOCKUP CLUTCH..... 725

5-5 REMOVING OIL PAN, FILTER,VALVE BODIES......... 726

5-6 REMOVING TORQUECONVERTER AND PTO

COMPONENTS ......... 728

5-7 REMOVING CONVERTERHOUSING

a Housing with 2-Bolt TopCover (no retarder) 730

5-9 REMOVING FORWARD,FOURTH, THIRD

CLUTCHES .......... 5 -11 730

5-12 REMOVING REARCOMPONENTS ............... 732

5-13 REMOVING CENTER SUPPORT,GEAR UNIT, SECOND

CLUTCH ....................... 734

667
http://0.0.0.0/http://0.0.0.0/


30/94



Section 6. REBUILD OF SUBASSEMBLIES

6-1. SCOPE OF SECTION 6... 736

6-2. GENERAL INFORMATION FORSUBASSEMBLY REBUILD. 736

6-3. FLYWHEEL, LOCKUPCLUTCH, CONVERTERTURBINE.......................... 736

6-4. CONTROL VALVE BODYASSEMBLY ...................... 738

6-5. LOW TRIMMER VALVE BODYASSEMBLY ...................... 743

6-6. LOW SHIFT VALVE BODYASSEMBLY ...................... 743

6-8. TORQUE CONVERTERSTATOR ASSEMBLY....... 744

6-9. TORQUE CONVERTER PUMPASSEMBLY ...................... 745

6-10. CONVERTER HOUSINGWITH 2-BOLT TOPCOVER, FRONT SUPPORT,OIL PUMP ........................ 746

6-17. FORWARD CLUTCH ANDTURBINE SHAFT ............ 750

6-18. FOURTH-CLUTCHASSEMBLY...................... 754

6-19. CENTER SUPPORTASSEMBLY...................... 756

6-22. REAR COVER ASSEMBLY 758

6-23. TRANSMISSION HOUSING 762

6-24. LOW PLANETARYCARRIER ASSEMBLY

......................................... 763

6-25. ADAPTER HOUSINGASSEMBLY...................... 764

6-26. GEAR UNIT AND MAINSHAFT ASSEMBLY......................................... 765

668
http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/


31/94



Section 6. (Continued)

6-29 FLEX DISK ASSEMBLY... 767

6-30. FRONT PLANETARYCARRIER ASSEMBLY..... 767

6-31. CENTER PLANETARYCARRIER ASSEMBLY769

6-34. REAR PLANETARY

CARRIER ASSEMBLY770

6-35. GOVERNOR INSPECTION 771

6-36. TORQUE SPECIFICATIONS. 772

Section 7. ASSEMBLY OF TRANSMISSION FROM SUBASSEMBLIES

7-1. SCOPE OF SECTION 7 773

7-2. CLUTCH CLEARANCES 773

7-4. ESTABLISHING CLUTCHCLEARANCES, SELECTINGCENTER SUPPORT SNAP-RING 774

7-6. INSTALLING FIRST CLUTCH,GEAR UNIT, SECONDCLUTCH, CENTERSUPPORT............... 777

7-7. INSTALLING REARCOMPONENTS.... 779

669
http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/


32/94



Section 7. (Continued)

7-11 INSTALLING FOURTH,

THIRD, FORWARDCLUTCHES ...................... 781A

7-12. INSTALLING TORQUECONVERTER HOUSING

....................................... 782

7-15. INSTALLING TORQUECONVERTER PUMP,STATOR ASSEMBLIES... 784

7-18. INSTALLING FLYWHEEL,

LOCKUP CLUTCH ANDTORQUE CONVERTERTURBINE ......................... 787

7-19. INSTALLING EXTERNALCOMPONENTS......................... 789

7-20 REPLACING OUTPUTSHAFT SEAL, BEARINGSPEEDOMETER DRIVEGEAR (in vehicle) ............ 790

7-21. CHECKING SHIFT POINTS 790

7-22. POWER TAKEOFFCOMPONENTS......................... 791

Section 8. WEAR LIMITS AND SPRING DATA

8-1. SCOPE OF SECTION 8... 792

8-2. WEAR LIMITS DATA. ...... 792

8-3. SPRING DATA................. 792

8-4. WEAR LIMITS CHART792(charts)............................. 793

8-5. CONTROL SYSTEM SPRINGCHARTS .......................... 792(charts)............................. 797

670
http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/http://0.0.0.0/


33/94



FOLDOUTS(back of manual)

Cross-section Views

2. Model HT 750CRD transmission

Schematic Views

5. Model HT 750CRD transmission hydraulic system

Exploded Views

A, 7. Flex disk and flywheel assembliesB, 7. Lockup clutch and torque converter

A, 8. Oil pump and converter housingB, 8. Converter housing and ground sleeve

B, 10. Front support and valve assembly

A, 11. Forward clutch assemblyB, 11. Fourth-clutch assembly

A, 12. Third-clutch, center support, and second clutch

A, 13. Gear unit and main shaft assembly (HT 750CRD)

A, 14. Transmission housing, oil filter and oil pan

B, 14. First clutch

A, 15. Adapter housing, low-clutch plates and low carrier

A, 16. First and low piston, rear cover, output shaft and governorB, 16. Control valve assembly

A, 17. Low shift and low trimmer valve body assembly

671


34/94

TRANSMISSION TRUCK SERVICE MANUAL

Para 1-1/1-4

Section 1. GENERAL INFORMATION

1-1. SCOPE OF MANUAL

a. Coverage. This Service Manualdescribes the operation, maintenance, and overhaulprocedures for the HT 750CRDautomatic transmission (fig. 1-3 AND 1-4 -). Themajor components of the transmission are discussed,and the function and operation of the hydraulicsystem and torque paths are explained. Detailedinstructions are provided for disassembly, rebuild andassembly. Wear limits information, par t s inspectionprocedures, and torque specifications are alsoincluded.

b. Illustrations. The text is illustrated with

photographs, line drawings, and cross-section views.The overhaul procedures are illustrated mainly byphotographs. Line drawings are used to supplementdetailed assembly procedures; cross-section viewsillustrate the torque paths and relationship ofassembled parts. Cross-section views, color-codedschematics of the hydraulic system, and all explodedviews are presented on foldout pages at the back ofthe manual.

1-2. SUPPLEMENTARY INFORMATION

Supplementary information will be issued, as

required, to cover any improvements which mayoccur after publication of this manual. Check withyour dealer to insure you have the latest information.

1-3. ORDERING PARTSa. Transmission Nameplate. The

nameplate (fig. 1-7) is located on the right-rear sideof the transmission. The nameplate displays thetransmission serial number, part number (assemblynumber), and model number. All three of these mustbe supplied when o r d e r in g replacement parts orrequesting service information.

b. Parts Catalog. All replacement parts

should be ordered from your dealer. These parts arelisted in the current HT 700 Series Parts Catalog (SA1268). Do not order by illustration item numb e r sused on exploded views in this manual.

1-4. GENERAL DESCRIPTION

a. Automatic Shifting. Automatic shifting isaccomplished in all ranges. THE DESIGNINCORPORATES FIVE SPEEDS FORWARD AND

ONE REVERSE.THE TRANSMISSION WAS

DESIGNED FOR OPERATION WITH A DIESELENGINE.

b. Torque Converter. A simple, 3elementtorque converter (fig 1-4) transmits power from theengine to the transmission gearing. The torqueconverter serves as both a fluid coupling and atorque multiplier.

THE TORQUE CONVERTETER USED IN THIS

TRANSMISSION HAS A STALL RATIO OF 2.8:1.

c. Lockup Clutch. This clutchautomatically locks the turbine element of the torqueconverter to the flywheel. When the vehicle attainssufficient speed, hydraulic pressure automatically app

lie s the lockup clutch. When the lockup clutch isapplied, the engine output is directed to thetransmission gearing at a 1:1 speed ratio. Adecrease in speed automatically releases the lockupclutch.

672


35/94


GENERAL INFORMATION

Fig. 1-4. Model HT 750 transmission-right-front view

673


36/94

TRUCK SERVICE MANUAL

GENERAL INFORMATION

Fig. 1-7 Transmission name plate

e. Power Takeoff Provisions

(1) Transmissions are equipped withprovisions for mounting a power takeoff on the front,

upper-left side of the transmission housing.

(2) The PTO on the transmission housing i sconverter driven.

f. Planetary Gearing, Clutches.

(2) In THIS transmission, ratio for fiveforward speeds and reverse are established by fourplanetary gear sets. The planetary are controlled by sixhydraulic applied clutches. All gearing is in constantmesh.

1-5. OPERATING INSTRUCTIONS

a. Vehicle-Related Controls. For information oncontrols which are related to the vehicle, refer to the

vehicle service manual. Refer also to Drivers HandbookSA 1334.

b. Neutral (N). Place the shift selector at theneutral position before starting the engine. A neutrasafety switch (on the transmission or in the selectolinkage) prevents starting the engine while the selectolever is not at neutral. Apply the vehicle brakes and shifto neutral any time the engine is to be running while theoperator is not at the controls.

c. Forward Drive Ranges(1) Shifting from neutral. The engine should

be at idle speed when any shift from neutral to a driverange is made.

(2) Drive (D). This range is the moscommonly used forward range. It includes all forwardgears

To drive in this range, simply depress the acceleratorThe transmission will start in first (second on HT750DRD), and automatically upshift at the proper speedsthrough all gears. Downshifts also will occuautomatically, in relation to speed and throttle position.

(3) Drive 4 (4) In this range, the transmission

will start in first (second on HT 750DRD), andautomatically upshift, at the proper speeds, to the fourthgear.

(4) Drive 3 (3). In this range, the transmissionwill start in first AND automatically upshift, at the propespeeds, to third gear.

(5) Drive 2 (2). In this range, the transmissionwill start in first AND automatically upshift, at the propespeeds, to second gear.

(6) Drive 1 (1). In this range, the transmission

will start in first gear. No automatic upshift will occuunless governed speed is exceeded.

674

TRANSMISSION


37/94


HT 700D SERIES

Para 1-5/1-6d. Reverse (R). To move the vehicle backward,

idle the engine and shift the selector to the reverseposition. Depressing the accelerator will then cause the

vehicle to back up.

e. Range Selection. Drive (D) range should beselected for normal load, grade and traffic conditions withan open highway ahead. Drive 3 (3) should be selectedfor moderate grades and over-the-road operation withrestricted speeds. Drive 2 (2) is appropriate foroperating in heavy traffic. Drive 1 (1) should be selectedwhen need for speed control requires a hold conditionsuch as descending steep grades where additionalengine braking is required, or for operation on roughterrain.

g. Towing. All lubricating and clutch apply oil isprovided by an engine-driven pump. Because of t hepump location ahead of the transmission gearing andclutches, the pump cannot be motored by pushing o

towing the vehicle. Therefore, anytime that the vehiclemust be towed or pushed, the drive line must bedisconnected or the driving wheels must be lifted off theground.

1-6. SPECIFICATIONS AND DATAThe specifications, and data in the chart below

provide a quick reference to the major characteristics othe transmission.

675

TRANSMISSION


38/94


GENERAL INFORMATIONPara 1-6

SPECIFICATIONS AND DATA CHART

HT 750CRD

Rating:Input torque (net installed) ............................................................. 1130 lb ft.

(1532 Nm) (max)Input speed (max).......................................................................... 3000 rpmInput horsepower (net

installed) .................................................................................. 400298 kW (max)

Mounting:Engine............................................................SAE 1 automotive housingVehicle ...........................................................Six-hole SAE 2 mounting pad (Earlier models have

four-hole SAE 1 mounting pad)Drive...............................................................Flex disk

Rotation:Input ...............................................................ClockwiseOutput (in forward ranges) .............................Clockwise

Torque converter:Type...............................................................Single-stage, poly-phase, 3 elementConverter model ............................................TC 470Torque multiplication ratio

(at stall)....................................................2.8:1Lockup clutch.................................................Automatic in selected ranges

Gear Data.............................................................Planetary straight-cut spur, constant mesh

Clutches................................................................Oil cooled, hydraulically actuator, spring released, self-

compensating for wear

Sump ....................................................................Integral

Oil systems:Oil pump (input) .............................................Engine driven, positive displacementOil pump (scavenge)......................................Engine driven, positive displacement, spur gear type.Oil filter...........................................................External, Suction screen (in sump)Oil capacity (less

external circuits) ......................................8 US gal (30.3 litres) (approx.)Initial fill (as received

from factory) ............................................6 US gal (22.7 litres) (approx.)Refill (oil and filter

changed)...................................................6 5 US gal (24 6 litres) (approx.)Oil type...........................................................Above -30F (-34C) hydraulic transmission fluid type

DEXRON Below -30F (-34C), hydraulic trans-mission fluid type DEXRON -auxiliary preheatrequired to raise temperature in sump and externalcircuit.

Oil temperature:....................................................Converter-Out(To Cooler) Sump

Converter Operation ......................................300F (149C) 250F (121C)Lockup Operation...........................................250F (121C) 250F (121C)

Dexron is a registered trademark of General Motors.

676

TRANSMISSION


39/94


HT 700D SERIES TRANSMISSIONSPara 1-6

SPECIFICATIONS AND DATA CHART - Continued

HT 750CRDOil pressure:

Main pressure- Idle 600 RPM......................................................90 psi

(621 kPa)-min- Stall 1200 RPM ..................................................140-175 psi

(965-1206 kPa)Lockup pressure ............................................Must be within 10 psi (69 kPa) of main pressureLubrication pressure ......................................35-45 psi (241-310 kPa)Converter-out pressure..................................40-80 psi (276-552 kPa)Rear governor pressure.................................Refer to table at end of section I

Parking brake provision:Type...............................................................12 x 5 (304.8 x 127.0 mm) (customer supplied)Weight............................................................50 lbs (22.68 kg)

Drive range and sequences:

HT 750CRD ...................................................Reverse, neutral, 1-2-3-4-5, 1-2-3-4, 1-2-3, 1-2, 1

Drive range and shift control ................................Mechanical (external)

Shifting mechanism..............................................Hydraulic (internal control)

Shift modulation (upshift anddownshift).......................................................Mechanically actuated (cable, cam, modulator valve)

Neutral start and reversesignal switches...............................................Supplied by customer

Speedometer drive:Type...............................................................Spiral gear

Drive gear data ..............................................6-tooth, Rt helix angleDriven gear ....................................................Supplied by customer

Dry weight.............................................................HT 750CRD

Standard unit..................................................926 lb (420 kg)

(housing, rotor, valve body)

Power takeoff mounting (optional)

Transmission housing, top(40 from vertical) ....................................Converter driven

677


40/94


GENERAL INFORMATIONPara 1-6

Power takeoff gear backlash ................................Refer para 7-20

Output flange........................................................Supplied by installer

Transmission Ratios (mechanical*)

Range Clutches engaged Ratio

HT 750CRD Neutral LowFirst Forward and low 3.19:1Second Forward and first 1.89:1Third Forward and second 1.55:1Fourth Forward and third 1.24:1Fifth Forward and fourth 1.00:1Reverse Fourth and low 7.97:1

*Overall torque multiplication ratio of transmission (output stalled) is the product of the converter torque multiplication ratioand the mechanical (gear) ratio.

HT 700 SERIES GOVERNOR PRESSURE

Governor Governor Pressure (psi) *At rpm

6834473 103-112 16506834864 83-91 16506836769 59-65 1650

*May be read from engine tachometer during lockup in highest gear.

678


41/94


Para 2-1/2-4Section 2. DESCRIPTION AND OPERATION

2-1. SCOPE OF SECTION 2This section describes the transmission components

and explains their functions. Also explained are the

hydraulic system and torque paths.

2-3. MOUNTINGa. To Engine. Converter housing 16 (A, foldout 8)

is machined to provide an SAE 1 mounting flange. Thisflange is mated with an SAE 1 bolt circle at the rear ofthe engine.

b. To Vehicle. An SAE 2 width engine typemounting pad is provided on each side of converterhousing 16 (A, foldout 8). Each pad has six 5/8-11tapped holes. Earlier models provided four 5/8-11tapped holes on an SAE 1 type mounting pad.

2-4. INPUT DRIVE

A steel laminated flex disk assembly 2 (A, foldout 7)connects the engine crankshaft and transmissionflywheel assembly 10. This flywheel serves as theengine flywheel. The inner circumference of the flexplate assembly bolts to an adapter which, in turn, bolts tothe engine crankshaft. The plates outer circumferencebolts to flywheel 12. The flywheel is bolted to torqueconverter pump 22 (B, foldout 7). Starter ring gear 11(A, foldout 7) is shrunk onto the flywheel.

2-5. TORQUE CONVERTER

a. Description (B, foldout7). The torque converte

consists of three elements pump assembly 21, stator 9and turbine 7. These are vaned elements which are casaluminum. Pump assembly 21 is the input element and isdriven by the engine through the flywheel. Turbine 7 isthe output element and is splined to forward clutch andturbine shaft assembly 5 (A, foldout 11). Stator 9 (Bfoldout 7) is the reaction (torque multiplying) elementThe stator is supported on free-wheel roller race 14which is splined to a stationary ground sleeve. Thisstator arrangement provides an over-running clutchwhich permits the stator to rotate freely in one directionbut locks in the opposite direction.

b. Operation

(1) The torque converter assembly iscontinually filled with oil, which flows through theconverter to cool and lubricate it. When the converter isdriven by the engine, the pump vanes throw oil againsthe turbine vanes. The impact of the oil against theturbine vanes tends to rotate the turbine.

(2) The turbine, splined to the turbine shafttransmits torque to the transmission gearing. At engineidle speed, the impact of oil against the turbine vanes isnot great. At high engine speed, the impact is muchgreater than at idle, and high torque is produced by the

turbine.

(3) Oil thrown into the turbine flows to thestator vanes. The stator vanes change

679

TRANSMISSION


42/94


Para 2-5/2-8

DESCRIPTION AND OPERATION

the direction of oil flow (when the stator is locked againstrotation), and directs the oil to the pump in a directionthat assists the rotation of the pump. It is the redirection

of the oil in a manner to assist the pump that enables thetorque converter to multiply input torque.

(4) Greatest torque multiplication occurs whenthe turbine is stalled and the pump is rotating at itshighest speed. Torque multiplication decreases as theturbine rotates and gains speed.

(5) When turbine speed approaches thespeed of the pump, oil flowing to the stator beginsstriking the backs of the stator vanes.

This rotates the stator in the same direction as the

turbine and pump. At this point, torque multiplicationstops and the converter becomes, in effect, a fluidcoupling.

(6) Thus, as explained in (1) through (5),preceding, the torque converter accomplishes three mainfunctions. It acts as a disconnect clutch because littletorque is transmitted at engine idle speed. It multipliestorque at low turbine/high pump speed to give greaterstarting or driving effort when needed. It acts as a fluidcoupling to efficiently transmit engine torque to thetransmission gearing during drive, other than idle orstarting.

2-6. LOCKUP CLUTCH

a. Description (B, foldout 7). The lockup clutchconsists mainly of three elements piston 3, clutch plate 4,and back plate 5. These elements a r e located insidethe flywheel. The piston and back plate rotate with theconverter pump. The clutch plate is located between thepiston and back plate and is splined to the converterturbine.

b. Operation (B, foldout 7). The lockup shift valvedirects clutch apply pressure to the lockup clutch pistonwhen sufficient rotational speed is achieved by the

forward clutch and turbine shaft assembly. The clutchapply pressure compresses the lockup clutch platebetween the piston and back plate, locking all threetogether. Thus, the converter pump and turbine arelocked together, and provide a direct drive from theengine. As rotational speed of the forward clutch andshaft assembly decreases, the lockup shift valve wilrelease the lockup clutch.

2-7. TORQUE CONVERTER HOUSING

Converter housing 16 (A, foldout 8) is machined fromcast aluminum. The front of the housing is machined to

mate with an SAE 1 engine flywheel housing. The reaof the housing is machined to accept either retarder plateassembly 2 or 19 (A, foldout 10), or front support andvalve assembly 1 or 30 (B, foldout 10), and transmissionhousing 7 (A, foldout 14). The converter housingencloses and supports the torque converter elementsand input-driven oil pump assembly 1 (A, foldout 8).

2-9. OIL PUMP ASSEMBLY

a. Description (A, foldout 8). Oil pump assembly 1consists mainly of three elements drive gear 4, d r iv e ngear 7 and pump body 3. The oil pump assembly is

680

TRANSMISSION


43/94


HT 700D SERIES TRANSMISSIONSPara 2-912-11

retained in the converter housing by six bolts. Drivengear 6 is supported in the pump body by gear shafts 5.

b. Operation (A, foldout 8). When the converterpump rotates, its rear hub drives pump drive gear 4.Gear 4 is in mesh with driven gear ASSEMBLY 6. Thus,as the gears rotate, oil is drawn into the inlet port and iscarried between the pump housing and the gear teeth tothe outlet s id e of the pump into the hydraulic system.

2-10. FORWARD SUPPORT AND VALVE ASSEMBLY

The forward support and valve assembly isconnected to the rear of the converter housing Itprovides support for the forward clutch and turbine shaft.Contained within the support assembly are three valvesmain pressure regulator valve assembly 3 (B, foldout10), lockup shift valve 8, and converter bypass valve 14.

2-11. FORWARD CLUTCH AND TURBINE SHAFT (A,foldout 11)

a. Function

(2) The forward clutch has multiple functions.When engaged with low clutch, it produces first gear.When engaged with first clutch, second, third or fourthclutches, it produces second, third, fourth or fifth gears,in that sequence.

b. Description

THE MODEL HAS A CLUTCH HOUSING WITH ATURBINE SHAFT ATTACHED

ten clutch plates, a piston, a forward clutch hub and afourth-clutch driving hub.

(2) The clutch housing contains an ocollector ring attached to its outer diameter and works inconjunction with a pitot tube to produce front governopressure.

The clutch housing contains the forward clutch pistonpositioned inside the housing in its bore, retained bytwenty springs, a spring retainer and a snapring.

(3) Five of the clutch plates are internalsplined, while the remaining five are external-tangedThe internal-splined plates are attached to the forwardclutch hub. The external-tanged plates are attached tothe internal grooves of the forward clutch housing.

c. Operation (A, foldout 11)

(1) Clutch housing and shaft assembly 5rotate when the converter turbine rotates. Fourth-clutchdriving hub 23 also rotates causing the internal-splinedplates of the fourth-clutch pack to rotate.

(2) When hydraulic pressure is directed to thefront side of piston 13, clutch plates 21 and 22 arecompressed together. This locks forward-clutch hub 20to the forward clutch housing. Since hub 20 is splined tothe transmission main shaft, the shaft will rotate with the

hub, at input speed.

(3) The simultaneous application of twoclutches is necessary to produce one forward or onereverse gear. The forward clutch is applicable only inforward gears (refer to b .(1), (2), above). When theconverter turbine rotates, and the forward clutch isapplied, the main shaft drives the components of thegear unit which in turn drive the output shaft.

(4) Rotation of the oil (pitot)collector ringdirects oil against the front pitot tube any time theconverter turbine rotates. Thus, an increase in turbine

speed produces a proportional increase in front governopressure.

681

TRANSMISSION


44/94


DESCRI PTION AND OPERATIONPara 2-1212-13

2-12. FOURTH CLUTCH (B, foldout 11)

a. Function

(2) The fourth clutch has a dual function.Engaged with the forward clutch, it produces fifth gear.Engaged with the low clutch, it produces reverse gear.

b. Description. The fourth clutch contain ten clutchplates, a clutch piston housing and a piston. Five platesare internally splined and five are externally tanged. Thepiston is positioned inside the clutch housing in its boreand retained by twenty piston return springs, a springretainer and a snapring.

c. Operation (B, foldout 11)(All models)

(1) Internal-splined clutch plates 4, driven bythe fourth-clutch driving hub, rotate any time the inputshaft and the forward clutch housing assembly rotates.

(2) When hydraulic pressure is directed to theback side of fourth-clutch piston 9, the pistoncompresses clutch plates 4 and 5 together. This locksinternal-splined plates 4 to external-tanged plates 5, and,in turn, to clutch housing 14.

(3) Since center sun gear and shaft assembly23 (B, foldout 12 or A and B, foldout 13) is splined to theclutch housing, it will also rotate at input speed.

2-13. SECOND, THIRD CLUTCHES, AND CENTER

SUPPORT (A, foldout 12)

a. Function Differs Among Models

(2) The second and third clutches performonly one function. When engaged with forward clutchthe second clutch produces third gear, while the thirdclutch produces fourth gear.

b. Description (1) The second and third clutchesare composed of two identical pistons, twenty-one clutch

plates (13 in second clutch; 8 in third clutch) and a centesupport.

(2) Two pistons 10 and 21 are positionedback-to-back in the bores of center support housingassembly 16. Each piston is retained in its bore bytwenty piston return springs 9 or 22, a return springretainer 8 or 23, four self-locking retainer rings 7 or 24and snap-rings 5 or 25.

(3) Eight clutch plates are required for thethird clutch (four internal-splined and four external-tanged plates). The internal-splined plates are attachedto the outside diameter of the fourth clutch housing and

are free to rotate. The external-tanged plates areanchored to the transmission housing and cannot rotate.

682

TRANSMISSION


45/94


HT 700D SERIES TRANSMISSIONS

Para 2 -13/2-14

(4) Thirteen clutch plates are required for the

second clutch. Six internal-splined plates are attached tothe splined area on the outside diameter of the frontcarrier assembly, and are free to rotate. The sevenexternal-tanged clutch plates a re anchored to thetransmission housing and cannot rotate.

(5) The center support assembly is housed inthe transmission and located by an anchor bolt. Thisinsures accurate oil passage hole alignment from thevalve body to the second and third piston cavities.

c. Operation of Third Clutch(A, foldout 12)

(1) When hydraulic pressure is directedthrough the oil passages in the center support to theback side of clutch piston 10, clutch plates 3 and 4 arecompressed together. This locks the fourth clutchhousing to the transmission housing, which prevents thefourth clutch housing and attached components fromrotation.clutch in conjunction with third clutch, a reaction within

the planetary gearing will produce a forward rotation tothe output shaft.

d. Operation of Second Clutch(A, foldout 12)

(1) When hydraulic pressure is directedthrough the oil passages in the center support to thefront side of clutch piston 21, clutch plates 26 and 27 arecompressed together. This locks the front planetarycarrier to the transmission housing, which prevents thecarrier from rotating.

(2) With the application of the forward clutchin conjunction with the second clutch, a reaction withinthe planetary gearing will produce a forward rotation tothe output shaft.

2-14. FIRST CLUTCH (B, foldout 14)

a. Function

(2) The first clutch has a single function.Engaged with the forward clutch, it produces secondgear.

b. Description. The first clutch contain thirteenclutch plates and a piston. Six are internal-splined clutchplates and seven are external-tanged clutch plates. The

external-tanged plates are held stationary by thetransmission housing, while the internal-splined platesare free to rotate. The piston for each model ispositioned in its respective bore and retained there byreturn springs and a spring retainer.

d. Operation (B, foldout 14)

(1) WHEN THE FIRST CLUTCH IS RELEASEDINTERNAL-SPLINED PLATES 2 ARE FREE TO

ROTATE. SINCE REAR PLANETARY RING GEAR 4

IS SPLINED TO THE INTERNAL PLATES, IT WILL

ALSO ROTATE FREELY.

(2) When hydraulic pressure is directed to theback side of piston 6 (A, foldout 15), the pistoncompresses clutch plates 1 (B, foldout 14) and 2together. This locks the rotating internal plates to thestationary external plates preventing ring gear 4 fromrotating.

(3) With the application of forward clutch inconjunction with first clutch (refer to a(2), above), areaction within the planetary gearing will produce aforward rotation at the output shaft.

2-15. LOW CLUTCH (A, foldout 15)

a. Function

(1) Only the five-speed transmissions includethe low clutch. Refer to FOLDOUT 2, ITEM 23, FOR ITSLOCATION

(2) The low clutch has a dual function. Whenengaged with the forward clutch, it produces first gearWhen engaged with the fourth clutch, it producesreverse gear.

b. DESCRIPTION. THE LOW CLUTCH :ONTAINTHIRTEEN CLUTCH PLATES AND A

683

TRANSMISSION


46/94


DESCRIPTION AND OPERATION

piston. Six are internal-splined clutch plates and sevenare external-tanged clutch plates. The external-tangedplates are held stationary by the adapter housing, whilethe internal splined plates are free to rotate. The piston

for each model is positioned in its respective bore andretained there by 28 piston return springs, the returnspring retainer, four retainer rings and a snapring.

c. Operation (A, foldout 15)

(1) When the low clutch is released, internal-splined clutch plates 15 are free to rotate. Since lowplanetary ring gear 14 is splined to internal plates 15, itwill also rotate freely.

(2) When hydraulic pressure is directed to theback side of low piston 6 (A, foldout 15), the piston c o mpresses clutch plates 15 and 16 together. This locksrotating internal-splined plate 15 to stationary external-tanged plate 16, preventing ring gear 14 from rotating.

(3) With the application of the forward orfourth clutch in conjunction wit h the low clutch, areaction within the planetary gearing will produce eitherforward or reverse rotation, respectively, at the outputshaft.

2-17. PLANETARY GEARING

a. Description (A, foldout 13)

(1) The planetary gearing i s composed of agear unit and main shaft assembly (A, foldout 13), thelow planetary carrier assembly 18 (A, foldout 15) and itssun gear and ring gear.

(2) The gear unit and main shaft assembly (A,foldout 13) contains three planetaries called front, centerand rear, so designated because of their location i nrelation to each other in the gear unit.

(3) Each of the three planetaries has a sungear and a ring gear, which are interconnected by themain transmission shaft and a connecting drum.

(4) The low planetary gear set is locatedbehind the gear unit and main shaft assembly. Re f e to figure 2-9. It contains a sun gear, a carrier assemblyand a ring gear. The sun gear is splined to the main

shaft, and the rear carrier is splined to the low ring gearthereby interconnecting the four planetary systems.

(5) This interconnection of the planetary inputreaction, and output elements and connections with theforward and fourth clutches produces five forwardspeeds and one reverse speed.

b. Operation (A, foldout 13)

(1) The front planetary assembly 5, used inconjunction with the center planetary assembly 16produces third gear when the forward and secondclutches are applied (fig. 2-11).

(2) The center planetary is active in thirdfourth, fifth and reverse gears.

(3) The rear planetary carrier assembly 38, isrequired in second, third, fourth and fifth gears. Insecond gear, with the application of forward and firstclutches, it singularly transmits torque, at a reductionthrough the low carrier to the output shaft (fig. 2-10). Inthird, fourth and fifth gears its only function is in thetransmitting of torque through the low carrier to theoutput shaft.

(4) The low planetary carrier assembly 18 (Afoldout 15), is used in all gears. In first gear, torque istransmitted through the main shaft to low sun gear andthen to the low carrier assembly. With the application othe forward and low clutches, the torque is thentransmitted by the carrier, at a reduction, to the outputshaft. In reverse gear, torque is transmitted through thefourth clutch housing, sun gear shaft assembly 23 (Afoldout 13), center carrier assembly 16 and main shaftassembly 34 to the low sun gear and carrier. With theapplication of fourth and low clutches, the torque is thentransmitted by the carrier, at a reduction, to the outputshaft (fig. 2-14).

NOTEIn fifth gear, because both the forwardand fourth clutches are engaged, all fourplanetaries rotate as a unit. This givesdirect drive through the transmission.

684

TRANSMISSION


47/94


48/94


DESCRIPTION AND OPERATIONPara 2-23/2-26

(2) The oil filter screens all oil entering thehydraulic system.

2-25. REAR COVER (A, foldout 16)

Rear cover 14 is made of cast iron and machined toreceive governor assembly 38 and first or low clutchpiston 4. The rear cover provides support for outputshaft assemblies 19. A parking brake mounting faceis also provided on the rear surface. The cover is therear closure member and is attached to the adapterhousing by twenty-four bolts 17 and 36.

2-26. HYDRAULIC SYSTEMa. System Functions. The hydraulic system

generates, directs, and controls the pressure and flow of

the hydraulic fluid within the transmission. The hydraulicfluid (transmission oil) is the power transmitting mediumin the torque converter. Its velocity drives the converterturbine. Its flow cools and lubricates the transmissionand its pressure applies the clutches.

b. System Schematics. A Color-coded foldoutillustration of the hydraulic system IS presented at theback of this manual (foldouts 5, ). Each illustrationrepresents the system as it would function during neutraloperation and with the engine idling.

c. Oil Filter, Pump Circuit(foldouts 5, )

(1) Oil (blue) is drawn from the sump(transmission oil pan) through a fine-mesh filter screenby the input-driven pump assembly.

(2) The oil (red) is discharged by the inputpump through an external filter (when so equipped) andinto the bore of the main pressure regulator valve.

(3) F or models equipped with a hydraulicretarder, the oil is discharged from two sections of theinput pump. The first section directs oil (red) to the

main-pressure regulator valve (item (2), above). Thesecond section directs oil (black and green) to thelubrication circuit, and assists in providing oil to theconverter-in circuit.

d. Main-Pressure Circuit(foldouts 5, )

(1) Main pressure (red) is regulate by themain-pressure regulator valve. Oil from the pump flowsinto the valve bore, through an internal passage in thevalve, to the upper end of the valve. Pressure at theupper end of the valve forces the valve downwardagainst the spring until oil (yellow) flows into theconverter-in circuit. When flow from the pump exceedsthe circuit requirement, the converter bypass valve opensand allows the excess to escape into the converter-outcircuit (orange).

(2) Although main pressure is controlledprimarily by the spring force below the regulator valve, itis also affected by the presence of forward regulatorpressure. When this pressure is not present at theregulator valve, main pressure is regulated at a highervalue.

(3) Main pressure (red) is directed to severa

points in the hydraulic circuit.

e. Converter, Cooler, LubricationCircuit (foldouts 5, )

(1) The converter circuit originates at themain-pressure regulator valve. Converter-in oil (yellowflows to the torque converter. Oil must flow through theconverter continuously to keep it filled and to carry off theheat generated within the converter.

(2) Converter-out oil (orange) leaving thetorque converter, is directed to an external cooler

(supplied by vehicle or engine manufacturer). When thetransmission includes a hydraulic retarder, converter-outoil flows through the retarder control valve

686

TRANSMISSION


49/94


HT 700D SERIES TRANSMISSIONS

before going to the cooler. A flow of air or water over orthrough the cooler removes the heat from thetransmission oil.

(3) Lubrication oil (green) is directed throughthe transmission to components requiring continuouslubrication and cooling. The lubrication oil then drainsinto the sump. Oil in excess of that required by thelubrication circuit escapes to the sump through thelubrication regulator valve.

f. Selector Valve, ForwardRegulator Circuits (foldouts 5, )

(2) THE SELECTOR VALVE can be shiftedinto seven lever positions; (R) reverse, (N) neutral, (D5)drive 5, (D4) drive 4, (D3) drive 3, (D2) drive 2, (D1) drive1. Attach of these positions, the selector valveestablishes the hydraulic circuit for operation in thecondition indicated.

NOTEThe quadrant designations listed aboveare not necessarily the same as those inthe vehicle.

(4) drive 1, drive 2, drive 3, drive 4 and drive 5are forward ranges. Anytime the vehicle moves forward,regardless of what range was selected, it starts in firstgear. Shifting is automatic in any of the above ranges,varying with vehicle speed and throttle position.

(6) The forward regulator pressure i s directedfrom the selector valve to the main-pressure regulatorvalve when the selector valve is in any position exceptreverse. In neutral and all forward drive ranges, thisregulator pressure assists the pump pressure actingdownward upon the main pressure regulator valve. Inreverse, the neutral-forward pressure is absent from themain-pressure regulator valve. This allows the valvespring to exert its full force upward against the regulatorvalve, causing an increase in main pressure. Thisincrease in pressure is necessary for higher clutchpressures, to handle the high torque produced in reverse

gear.

g. Rear Governor Circuit

(1) Governor feed is merely main pressuredirected to the governor valve. A centrifugal-type g o v e

r n o r, driven by the transmission output, controls theposition of the governor valve. The position of thegovernor valve determines the pressure in the governorcircuit. When the transmission output is not rotatinggovernor pressure is negligible. When the transmissionoutput rotates, governor pressure varies with the speedof rotation.

(2) Governor pressure is directed to the shifsignal valves and to the governor accumulator valve.

(3) The governor accumulator valve is aspring-loaded valve in a straight bore. The accumulatovalve absorbs pressure surges and provides a moreuniform governor pressure.

h. Modulator Pressure Circuitfoldouts 5, )

(1) The modulator valve produces aregulated, reduced pressure which is derived from mainpressure. The valve is moved rightward by a spring athe left end of the valve when the throttle is closed. Thevalve is moved leftward by the cam and spring actionwhen the throttle is opened. When the spring force athe left of the valve is imbalance with the spring forceand modulator pressure at the right end of the valve

modulator pressure is regulated.

(2) When the throttle setting is increased, theupward (or downward) movement of the actuator camforces the modulator valve toward the left. This leftwardmovement reduces mod

TM 5-3805-254-14P-2 PART 7 IHC F-5070 DUMP TRUCK

Documents

Transcript of TM 5-3805-254-14P-2 PART 7 IHC F-5070 DUMP TRUCK