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ONE POSITION TWO POSITION THREE POSITION

VENTED PRESSURIZED RETURN ABOVE FLUID LEVEL RETURN BELOW FLUID LEVEL

LINES CROSSING LINES JOINING

TWO-WAY THREE-WAY FOUR-WAY

SPRING CONTROL VALVES RESTRICTION LINE RESTRICTION(FIXED)

2-SECTION PUMP

MAIN AUX.

SPRING(ADJUSTABLE)

VARIABILITY LINE RESTRICTION(VARIABLE)

LINE RESTRICTIONVARIABLE and PRESSURE

COMPENSATED

PRESSURECOMPENSATION

PUMP: VARIABLE andPRESSURE COMPENSATED

ENERGY TRIANGLESHYDRAULIC PNEUMATIC

MEASUREMENT

PRESSURE TEMPERATURE FLOW

ROTATING SHAFTS

UNIDIRECTIONAL BIDIRECTIONAL

PUSH-PULL LEVER PEDALGENERAL MANUAL PUSH BUTTON SPRING

MANUAL CONTROL SYMBOLS

HYDRAULIC MOTORS

FIXEDDISPLACEMENT

VARIABLE DISPLACEMENTNON-COMPENSATED

UNIDIRECTIONAL

BIDIRECTIONAL

HYDRAULIC PUMPS

FLUID STORAGE RESERVOIRS

CROSSING AND JOINING LINES

VALVE ENVELOPES VALVE PORTS

BASIC COMPONENT SYMBOLS

FLUID CONDITIONERPUMP or MOTOR

FLUID POWER SYMBOLS

FIXEDDISPLACEMENT

VARIABLE DISPLACEMENTNON-COMPENSATED

UNIDIRECTIONAL

BIDIRECTIONAL

VALVES

PILOT CONTROL SYMBOLSRELEASED PRESSURE

EXTERNAL RETURN INTERNAL RETURN

REMOTE SUPPLY PRESSURE

SIMPLIFIED COMPLETE INTERNALSUPPLY PRESSURE

ACCUMULATORS

SPRING LOADED GAS CHARGED

SOLENOID or MANUAL

SOLENOID and PILOT

SOLENOID and PILOT or MANUAL

COMBINATION CONTROLS

SOLENOID SERVO THERMAL DETENT

HYDRAULIC AND PNEUMATIC CYLINDERS

DOUBLE ACTINGSINGLE ACTING

BASICSYMBOL

SPRINGLOADED

CHECK VALVES

TWOPOSITION

INFINITEPOSITIONING

FLOW IN ONEDIRECTION

FLOW ALLOWED INEITHER DIRECTION

THREEPOSITION

CROSSFLOW

PARALLELFLOW

INTERNAL PASSAGEWAYS

NORMAL POSITION

A B

P T

A B

P TSHIFTED POSITION INFINITE POSITION

CONTROL VALVES

ATTACHMENT

MANUAL SHUTOFF

SHUTTLE PILOTCONTROLLED

Hydraulic Symbols (Electrical)

Electrical Symbols Table

325-AG135 PK-14

Circuit IdentificationNumber

Wire Color Wire Gauge

Harness identification codeThis example indicateswire 135 in harness "AG".

325-PK-14

Wire Gauge

Wire Color

Circuit Number Identification

Wire Number Identification Codes

Current Standard

Previous Standard

Electrical Schematic Example Hydraulic Schematic Example

325-PK

Wire ColorCircuit Number Identification

B A

Wire

Wire

(EXAMPLE VALVE)

Current Standard

Transducer(Fluid)

Transducer(Gas / Air)

G

Generator

Electrical WirePressure Switch

MElectric Motor

Pressure Switch (Adjustable)

Temperature Switch

T

PressureSymbol

TemperatureSymbol

LevelSymbol

FlowSymbol

Electrical Symbols (Electrical)

777F:JRP1-UP

777F OEM:JXP1-UP

Volume 1 of 2: Brakes and Hoist©2012 CaterpillarAll Rights Reserved

Printed in U.S.A.

RENR8305-03March 2012

777F and 777F OEM Off-Highway TruckHydraulic System

TapNumber Description Schematic

Location A LEFT REAR SERVICE BRAKE F-8 B RIGHT REAR SERVICE BRAKE B-8 C REAR SLACK ADJUSTER INPUT D-8 D CAB MANIFOLD RESOLVER OUTPUT F-4 E ACCUMULATOR CHARGING OUTPUT D-4 F BRAKE CHARGING PUMP OUTPUT D-4 G LEFT PARK BRAKE D-7 H RIGHT PARK BRAKE C-7 J FRONT SLACK ADJUSTER INPUT E-1 K DRY FRONT BRAKE INPUT E-1 L CYLINDER HEAD END A-3 M CYLINDER ROD END A-3 N HOIST PUMP OUTPUT C-4 R HOIST VALVE RAISE PILOT D-3 P HOIST VALVE LOWER PILOT B-3 S BRAKE COOLING INPUT B-7

Tap LocationsPressure, Sampling, and Sensor (Volume 1)

ItemNumber Description Part

NumberSchematicLocation

1 TANK GP (HYD & TRANS) 258-9852 A-42A PUMP GP (BRAKE CHARGING) 255-5478 B-52B PUMP GP (BRAKE CHARGING) 256-0561 B-43 PUMP GP (BRAKE COOLING) 255-5478 B-4

4A PUMP GP (HOIST) 255-5478 B-44B PUMP GP (HOIST) 256-0561 B-45 VALVE GP- ACCUMULATOR CHARGING 257-0273 D-56 VALVE GP-MTG & (PARKING BRAKE) 289-0585 F-67 CONTROL GP-HYD (BRAKE RETRACT) 222-4744 D-78 ADJUSTER GP- SLACK 205-0557 D-89 ADJUSTER GP-SLACK 8X-7921 D-2

10 BRAKE GP-SERVICE & PARK 243-5545 B-8, F-811A BRAKE GP-SERVICE (FRONT BRAKES) 8X-3810 D-1, F-111B BRAKE GP-SERVICE (FRONT BRAKES) 243-5551 D-1, F-112 VALVE GP (CAB MANIFOLD) 261-1316 F-413 VALVE GP-CHECK 249-5521 E-414 SWITCH AS.- PRESSURE 3E-7806 E-415 PUMP GP-ELECTRIC (BRAKE RETRACT) 230-2637 D-516 VALVE GP-DIVERTER 3G-2887 E-617 VALVE GP-RELIEF 228-7839 E-518 FILTER (BREATHER) 8X-4575 A-619 SWITCH AS.-PRESSURE 160-2609 F-620 ACCUMULATOR GP (BRAKE) 220-5692 E-521 PEDAL GP-BRAKE VALVE 261-1317 F-322 VALVE GP-CONTROL (HOIST) 245-1668 B-3, C-3, D-323 CYLINDER GP-TELESCOPING (HOIST) 171-1232 A-324 PLATE-ORIFICE (HOIST) 8X-7224 A-326 SCREEN AS. 7J-3723 A-427 SCREEN AS. (BRAKE COOLING) 6E-6640 B-6, C-728 CORE AS.-OIL COOLER 141-4109 B-6, C-729 FILTER GP-OIL 155-6061 C-535 PUMP GP-ELECTRIC (STEERING) 230-2637 D-647 SCREEN AS. 7J-0725 A-554 PUMP GP-ELECTRIC (ENGINE OIL) 230-2637 D-558 VALVE GP-CHECK 185-4026 E-559 VALVE AS.-SHUTTLE 8J-6875 E-3

Component Locations (Volume 1)

Purge Solenoid

COMPONENT LOCATIONS

BRAKING HOIST

10

7

232416

12617

18 234 205 14 1129

9

21

12 14

3515 54

27 28

11

8

619

22

10

2324 59

Shown in the visual is the new location of the hoist pump (4A, 4B). The hoist pump is a gear type pump and is attached to the brake cooling pump (3) and the brake charg-ing pump (2A, 2B). The hoist pump is now driven by the gears at the back of the engine.

4A

3

2A

4B

2B

20

Shown in the visual are the three brake accumulators for the 777F. The accumulators (20) are charged by the brake charging pump and supply the required oil flow to disengage the front and rear brakes. The outer accumulators are for the rear service brakes. The middle accumulator is for the parking brake and front service brakes.

A check valve in the circuit between the parking accumulator and the rear service accumulators allows only the parking brake accumulator to be filled when using the secondary electric pump.

6

This visual shows the parking brake valve (6) for the 777F which is located on the inside left frame rail behind the middle cross member. The parking brake release valve no longer works off pressurized air. This valve receives oil flow from the parking brake accumulator. Contained within the valve is a parking brake solenoid valve (3) and a purge solenoid valve (4).

Parking Brake Solenoid

E

F

The accumulator charging valve (5) is located on the left side of the frame by the brake accumulators This valve directs oil to the brake accumulators, brake cooling, and the tank. Once the accumulators are charged, the excess oil flow is sent to cool the brakes before returning to the tank.

The Brake ECM monitors the pressure in the service brake accumulators with pressure switch. If the pressure in the service brake accumulators are low, the pressure switch will open and the Brake ECM will signal the monitoring system to turn on the brake system-check indicator.

Pressure tap (E) is used to check the oil pressure in the service brake accumulators. Pressure tap (F) is used to check the charge oil pressure from the pump.

The accumulator charging valve contains a CUT-IN/CUT-OUT spool. Once the maximum brake system pressure is reached, the spool will shift and send the excess flow to brake cooling. As the system pressure continues to drop to the CUT-IN pressure setting, the spool will shift again and the system will charge to the CUT-OUT pressure setting. This process will continue to repeat as often as needed to keep the brake system fully charged. The CUT-IN/CUT-OUT pressure is checked at pressure tap (B).

The relief valve setting is set slightly higher than the CUT-OUT pressure setting. In the event that the CUT-IN/CUT-OUT valve spool fails, the relief valve will protect the system from extreme pressure. Relief valve can only be tested on a hydraulic test bench.

If the charge oil pressure is low at pressure tap (F), or the brake system never reaches the proper CUT-OUT pressure, check relief valve. If relief valve is set properly and the brake system is not reaching the specified CUT-OUT pressure, replace the accumulator charging valve. The CUT-IN/CUT-OUT spool is not adjustable.

5

Relief Valve

Pressure Switch

29

The brake system filter (29) is located on the left outer frame rear next to the left rear strut mount. The brake system filter has a bypass switch.

8

9

The 777F has two slack adjusters. The top visual is of the rear slack adjuster (8). The rear slack adjuster is located above the rear differential. The slack adjuster maintains a consistent feel and application of the brakes as the brake discs wear.

The lower visual is of the front slack adjuster (9). The front slack adjuster is located on the left strut frame support. The slack adjuster maintains a consistent feel and application of the brakes as the brake discs wear.

Shown in this visual is the diverter (towing) valve (16) for the 777F. The diverter valve functions the same however has changed locations. The diverter valve for the 777F is now located on the left frame rail in front of the left front strut. The diverter valve must be manually shifted before towing.

Once the valve is shifted, oil flow from the electric secondary pump is directed to the parking brake valve to release the parking brake. The relief valve (17) limits the maximum pressure when using the towing pump.

16

17

4A 4B

Shown in the visual is the new location of the hoist pump (4A, 4B).

Shown in the visual is the new location of the hoist control valve (22). The valve (22) is located behind the engine on the right side of the frame. The valve (22) will function the same as the hoist control valve on the 777D.

22

R

P

M L

Shown in the visual to the left are the pressure taps for the hoist control valve. The pressure tap (R) checks the pilot pressure for the hoist lower solenoid. The pressure tap (P) checks the pilot pressure of the raise solenoid.

Shown in the visual to the right are the pressure taps for the hoist cylinders. These pressure taps are located on the cross-tube between the lower hoist cylinder mounts. The pressure tap (M) checks the pressure of the cylinder lower circuit. The pressure tap (L) checks the pressure of the cylinder raise circuit.

47

58

CAB

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DRAIN / RETURN LINE

HYDRAULIC CIRCUIT COLOR DESCRIPTIONSELECTRICAL CIRCUITSBRAKE CHARGING CIRCUIT PUMP

LOCK-UP CLUTCH VALVE PUMP CIRCUITBRAKE COOLING

HOIST PUMP CIRCUITPUMP SUPPLY LINE

HOIST CYLINDERS CIRCUIT

BRAKE CIRCUIT (FRONT AND REAR)

THIS SCHEMATIC IS FOR THE 777F AND 777F OEM OFF-HIGHWAY TRUCKPART #: 255-6188 CHG 07Components are shown installed on a fully operable machine with the key and engine off and transmission shifter in neutral.

Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations

LINE PATTERNS

Drain / Return Lines

Component Group

Pilot / Load Sensing Pressure

Pressure Line

Attachment

Air Line

CALLOUTS

Taps (Pressure, Sampling,Sensor) by letter

Components by number

YY

52

7

78 6 5 4 3 2 1

A

B

C

D

E

F

1234568

F

E

D

C

B

A

A

B

D

E 59

8

From Torque ConverterLock-up Clutch Pilot

(Volume 2, F-3)

ADJUSTER GP - SLACK

RIGHT REAR

LEFT REAR

M

P

T

A

1

4

5

P1

T1

A1

PARK BRAKE SOLENOID

BLEEDDOWNSOLENOID

3

ECM

P2

LEFTFRONT

RAISE SOLENOID

LOWER, FLOAT, SNUB SOLENOID

BRAKE COOLING RELIEF

LOWER

FLOAT

SNUB

HOLD

RAISE

RAISE RELIEF

LOWER RELIEF

DUAL STAGE SIGNAL SPOOL

MAIN RELIEFDUMP SPOOL

7

10

10

28 27

11A

11A

9

20 13

14

5

2B 4B

1535 54

11B

11B

2324

22

1

4A32A

28 27

1221

FRONT BRAKES

WET DRY

LEFTFRONT

RIGHTFRONT

RIGHTFRONT

1716

58

6

H

G

S

18

N

R

P

ML

D

E

F

29

C

B

A

K

From Torque Converter Lock-up Clutch.(Volume 2, F-3)

From Torque Converter Lock-up Clutch. (Volume 2, E-2)

From Torque Converter(Volume 2, F-4)

See Note A

See Note A

See Note A

19

47 26

14

J

Note A: Dry brake configuration

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ONE POSITION TWO POSITION THREE POSITION

VENTED PRESSURIZED RETURN ABOVE FLUID LEVEL RETURN BELOW FLUID LEVEL

LINES CROSSING LINES JOINING

TWO-WAY THREE-WAY FOUR-WAY

SPRING CONTROL VALVES RESTRICTION LINE RESTRICTION(FIXED)

2-SECTION PUMP

MAIN AUX.

SPRING(ADJUSTABLE)

VARIABILITY LINE RESTRICTION(VARIABLE)

LINE RESTRICTIONVARIABLE and PRESSURE

COMPENSATED

PRESSURECOMPENSATION

PUMP: VARIABLE andPRESSURE COMPENSATED

ENERGY TRIANGLESHYDRAULIC PNEUMATIC

MEASUREMENT

PRESSURE TEMPERATURE FLOW

ROTATING SHAFTS

UNIDIRECTIONAL BIDIRECTIONAL

PUSH-PULL LEVER PEDALGENERAL MANUAL PUSH BUTTON SPRING

MANUAL CONTROL SYMBOLS

HYDRAULIC MOTORS

FIXEDDISPLACEMENT

VARIABLE DISPLACEMENTNON-COMPENSATED

UNIDIRECTIONAL

BIDIRECTIONAL

HYDRAULIC PUMPS

FLUID STORAGE RESERVOIRS

CROSSING AND JOINING LINES

VALVE ENVELOPES VALVE PORTS

BASIC COMPONENT SYMBOLS

FLUID CONDITIONERPUMP or MOTOR

FLUID POWER SYMBOLS

FIXEDDISPLACEMENT

VARIABLE DISPLACEMENTNON-COMPENSATED

UNIDIRECTIONAL

BIDIRECTIONAL

VALVES

PILOT CONTROL SYMBOLSRELEASED PRESSURE

EXTERNAL RETURN INTERNAL RETURN

REMOTE SUPPLY PRESSURE

SIMPLIFIED COMPLETE INTERNALSUPPLY PRESSURE

ACCUMULATORS

SPRING LOADED GAS CHARGED

SOLENOID or MANUAL

SOLENOID and PILOT

SOLENOID and PILOT or MANUAL

COMBINATION CONTROLS

SOLENOID SERVO THERMAL DETENT

HYDRAULIC AND PNEUMATIC CYLINDERS

DOUBLE ACTINGSINGLE ACTING

BASICSYMBOL

SPRINGLOADED

CHECK VALVES

TWOPOSITION

INFINITEPOSITIONING

FLOW IN ONEDIRECTION

FLOW ALLOWED INEITHER DIRECTION

THREEPOSITION

CROSSFLOW

PARALLELFLOW

INTERNAL PASSAGEWAYS

NORMAL POSITION

A B

P T

A B

P TSHIFTED POSITION INFINITE POSITION

CONTROL VALVES

ATTACHMENT

MANUAL SHUTOFF

SHUTTLE PILOTCONTROLLED

Hydraulic Symbols (Electrical)

Electrical Symbols Table

325-AG135 PK-14

Circuit IdentificationNumber

Wire Color Wire Gauge

Harness identification codeThis example indicateswire 135 in harness "AG".

325-PK-14

Wire Gauge

Wire Color

Circuit Number Identification

Wire Number Identification Codes

Current Standard

Previous Standard

Electrical Schematic Example Hydraulic Schematic Example

325-PK

Wire ColorCircuit Number Identification

B A

Wire

Wire

(EXAMPLE VALVE)

Current Standard

Transducer(Fluid)

Transducer(Gas / Air)

G

Generator

Electrical WirePressure Switch

MElectric Motor

Pressure Switch (Adjustable)

Temperature Switch

T

PressureSymbol

TemperatureSymbol

LevelSymbol

FlowSymbol

Electrical Symbols (Electrical)

© Printed in U.S.A.

777F:JRP1-UP

777F OEM:JXP1-UP

Volume 2 of 2: Steering and Power Train2012 Caterpillar

All Rights Reserved

RENR8305-03March 2012

777F and 777F OEM Off-Highway TruckHydraulic System

TapNumber Description Schematic

Location T HMU INPUT E-7 U STEERING LOAD SENSE PILOT D-8 W LOCK-UP CLUTCH E-3 X LOCK-UP CLUTCH FILTER OUTPUT D-3 Y TRANS CHARGE FILTER OUTPUT F-3 Z TC OUTLET RELIEF VALVE F-4 V SOS C-8

Tap Locations Pressure, Sampling, and Sensor (Volume 2)

ItemNumber Description Part

NumberSchematicLocation

1 TANK GP (HYD & TRANS) 258-9852 C-415 PUMP GP-ELECTRIC (BRAKE RETRACT) 230-2637 D-618 FILTER (BREATHER) 8X-4575 C-425 FILTER GP-OIL 249-2306 D-230 TANK GP-HYD (STEERING) 249-2925 A-731 PUMP GP-PISTON (STEERING) 261-5630 B-632 VALVE GP-CHECK (STEERING) 175-7050 E-733 PUMP GP-METERING (STEERING) 195-6617 E-734 CYLINDER GP-(STEERING) 105-2440 F-735 PUMP GP-ELECTRIC (STEERING) 230-2637 D-6

36 SWITCH AS.- PRESSURE(STEERING PUMP OIL LOW PRESSURE) 313-5104 D-8

37 SWITCH AS.- PRESSURE (SECONDARY STEERING) 9X-4455 E-638 FILTER GP-OIL (STEERING) 173-0159 B-739 FILTER GP-HYD (STEERING) 249-2334 C-840 VALVE-BREAKER RELIEF 9T-0818 B-541 PUMP GP-GEAR (TORQUE CONV. SCAVENGE) 256-6123 D-342 FILTER GP 4T-4760 D-343 VALVE GP-MODULATING 244-3114 E-344 FILTER GP-OIL 244-0121 F-345 FILTER GP-OIL 270-5181 F-346 SWITCH AS.-LIQUID LEVEL 172-8660 B-247 SCREEN AS. 7J-0725 C-248 CONVERTER GP-TORQUE 249-5539 D-449 VALVE GP-RELIEF 3P-0349 F-450 PUMP GP-GEAR (TORQUE CONV. CHARGE) 256-6123 D-351 PUMP GP-GEAR (LOCK-UP CLUTCH VALVE PILOT) 256-6123 D-352 PUMP GP-GEAR (TRANSMISSION SCAVENGE) 256-6123 D-253 PUMP GP-GEAR (TRANSMISSION CHARGING) 256-6123 D-254 PUMP GP-ELECTRIC (ENGINE OIL) 230-2637 D-555 VALVE GP-RELIEF 3P-0348 C-356 CORE GP- OIL COOLER 4W-5056 C-257 VALVE GP-CHECK 268-3451 C-260 VALVE GP-RELIEF 268-3998 E-261 VALVE GP-MTG & 277-8869 C-8

Component Locations (Volume 2)

Shown in the visual to the left is the electric secondary steering pump (35) on the 777F. The pump and motor are the same as the 777D however the location has changed. The pump and motor are now located on the front crossmember. The secondary pressure switch (36) is also mounted next to the secondary steering pump. The pressure switch (36) detects if the wheels are being turned via the steering wheel when second-ary steering is applied. When the wheel is turned in a secondary steering condition, the pressure switch (36) will signal the Transmission/Chassis ECM and the QuickEvac function will be disabled.

Relief ValveRelief ValveSteering Disable Solenoid

53 52

55

49 43

51 50 41

42

Shown in the left visual is the 777F transmission charge filters. The 777F has two filters mounted on the cross member on the right side of the machine. Port (Y) is an S•O•S port. The rear filter housing also has a bypass switch. The bypass switch provides an input signal to the Caterpillar Monitoring System, which informs the operator if the filter is restricted.

Shown in this visual is the 777F torque converter charging filter (42). The charging filter is located on the right frame rail, behind the right front tire. The S•O•S port is located on the torque converter filter. S•O•S Port draws a sample from the outlet of the filter.

Shown in the top visual is the new five section gear pump. The gear pump is a different design then the previous 777D. The gear pumps are for the following circuits:

Torque converter scavenge (41)Torque converter charge (50)Lockup clutch valve pilot circuit (51)Transmission scavenge (52)Transmission charge (53)

Shown in the lower visual are some of the torque converter system components for the 777F. The torque converter systems are similar between the 777D and 777F. The torque converter inlet relief valve (55) and the outlet relief valve (49) will function the same. The lockup clutch valve (43) on the 777F is now an ECPC valve.

This view shows the torque converter lockup clutch filter. (X) is a pressure tap. The pressure indicated at tap (X) is pump pressure for the lockup clutch pilot circuit.

X

a b c d e f g h j

Y

Shown in this visual is the 777F ECPC transmission. This new transmission has pressure taps located on the outside of the transmission. This feature will aid in preventing contamination from entering the transmission as well as saving time when checking the pressures on the 777F transmission.

Lube oil pressure can be checked at tap (a).System pressure can be checked at tap (b).Clutch 6 pressure can be checked at tap (c).Clutch 5 pressure can be checked at tap (d).Clutch 7 pressure can be checked at tap (e).

Clutch 4 pressure can be checked at tap (f).Clutch 3 pressure can be checked at tap (g).Clutch 2 pressure can be checked at tap (h).Clutch 1 pressure can be checked at tap (j).

4544Z44

45

31

32

35 36

30

T

61

Shown in this visual is the steering pump (31) for the 777F. The steering pump is now mounted on the back of the new C32 ACERT engine. The steering pump is still a load sensing, pressure compensated, piston-type pump

Shown in this visual is the steering valve (32) for the 777F. The 777F uses the same steering valve as the 777D. The steering valve is located in the same place however the steering valve is mounted differently. The pressure tap (T) checks the pressure in the supply line to the HMU. If the supply oil pressure to the HMU is below specification, the relief valvemany need to be adjusted.

The steering disable valve (61) is located behind the shock on the right frame rail. When the steering disable solenoid valve is energized, the flow from the steering to the steering valve is blocked by the steering disable valve (61). This allows servicing behind the

W

Shown in the this visual is pressure tap (W) for the lockup clutch valve and pressure tap (V) for the outlet relief valve. The pressure indicated at tap (W) is the pressure in the lockup clutch. The pressure indicated at tap (Z) is the pressure inside the torque converter.

CAB

1264647 59 5225 6018

33

34 15 35 37 54

34

56

32 36 6131 42 3038394044 45

53 57515041

4955 4348

Shown in the visual to the right is the 777F steering system tank. The tank is located on the right platform. The 777F steering tank functions the same as the the 777D steering tank.

S•O•S

NOTE: The taps shown in this visual do not appear on the schematic.

COMPONENT LOCATIONS

POWER TRAIN

STEERING SYSTEM

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DRAIN / RETURN LINE

HYDRAULIC CIRCUIT COLOR DESCRIPTIONSELECTRICAL CIRCUITS

STEERING PUMP CIRCUIT

TRANSMISSION AND TORQUE CONVERTER SCAVENGE PUMP CIRCUIT

LOCK-UP CLUTCH VALVE PUMP CIRCUIT

BRAKE COOLING

PUMP SUPPLY LINE

TRANSMISSION CHARGE PUMP CIRCUIT

TORQUE CONVERTER CHARGE PUMP CIRCUIT

SECONDARY STEERING PUMP CIRCUIT

THIS SCHEMATIC IS FOR THE 777F AND 777F OEM OFF-HIGHWAY TRUCKPART #: 255-6188 CHG 07Components are shown installed on a fully operable machine with the key and engine off and transmission shifter in neutral.

Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations

LINE PATTERNS

Drain / Return Lines

Component Group

Pilot / Load Sensing Pressure

Pressure Line

Attachment

Air Line

CALLOUTS

Taps (Pressure, Sampling,Sensor) by letter

Components by number

YY

52

8 6 5 4 3 2 1

A

B

C

D

E

F

1234568

F

E

D

C

B

A

7

7

ECM

M

B

AC

D

E

A

B

LOAD SENSE STEERING SYSTEM

POWERTRAIN:TRANSMISSION AND TORQUE CONVERTER

15

35

54

535251

504155

4726 46

48

42

1

43

25

18

49

60

44 45

W

39

30

38

31

61

40

T

33

32

37

34

Z

X

Y

U

V

HYDRAULICCONTROLS

TORQUE CONVERTER

TRANSMISSION

LOCK UPVALVE

LOCK-UP CLUTCH PRESSURE

TO BRAKE COOLING

TO BRAKE COOLING

To Traction Control Valve

To Hoist Pilot Signal Resolver

To Rockford Fan Clutch Control(Attachment)

36

56

57