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Document. . . . . .: TM 1-1520-237-23 - [WP 0640 00] - 30 JULY 2010, MAIN TRANSMISSION

Frame title . . . .: REMOVAL [2 of 6]

Document date . . .: Mon Nov 08 13:46:38 2010

Printed at. . . . .: Mon Mar 11 18:19:26 2013

Page - 1

UH-60A EH60A Main transmission with all equipment (input modules, accessory modules, generators and hydraulic pumps) installed, weighs about 1200 pounds.Main transmission with all equipment, main rotor head, and swashplate installed, weighs about 2400 pounds. Main module alone weighs approximately 750 pounds.

UH-60L Transmission with all equipment (input modules, accessory modules, generators, and hydraulic pumps) installed, weighs approximately 1395 pounds. Maintransmission with all equipment, main rotor head, and swashplate and flight controls installed, weighs about 2448 pounds. Main transmission alone weighs

approximately 860 pounds.

If an overhead hoist capable of lifting main transmission with main rotor head and swashplate installed is available, it is easier to remove transmission with headinstalled and then remove head while on ground. If maintenance crane will be used, main rotor head and swashplate must be removed first.

Note

1. Make sure helicopter wheels are chocked.

2. Turn off all electrical and hydraulic power.

3. Open engine cowlings.

4. Open main rotor pylon sliding cover.

Damage to maintenance crane and helicopter will occur if maintenance crane is used to remove transmission with main rotor head and swashplate installed. Use sling

and overhead hoist to remove main transmission with main rotor head and swashplate installed.

Caution

5. If maintenance crane will be used, do this:

a. Assemble and erect crane (WP 1639 00).

b. Remove main rotor blades (WP 0585 00).

c. Remove main rotor head (WP 0556 00).

d. Remove swashplate (WP 0576 00).

e. UH-60L Remove fire extinguisher line from r ight firewall at STA 370.0 (WP 1212 00).

6. If overhead hoist and sling will be used, do this:

a. If deice kit is installed, remove main rotor blade deice slipring assembly (WP 1233 00).

b. Remove main rotor blades (WP 0585 00).

c. UH-60L Remove fire extinguisher line from r ight firewall (WP 1212 00).

7. Remove transmission drip pan (WP 0266 00, WP 0267 00, WP 0268 00, orWP 0269 00).

8. Remove magnetic drain plug from valve body ( Figure 1).

Gear Box

If main transmission is to be removed and reinstalled to facilitate other maintenance, draining oil from transmission is not required. Ensure all lines and ports are

capped to prevent oil contamination or debris entering the transmission.

Note

9. Install drain tube by turning clockwise until locked in position. Drain oil into 10 gallon container.

10. Remove drain tube from drain port, by turning counterclockwise and pulling out. Install new packing on magnetic drain plug.

11. If valve body is damaged, remove by turning counterclockwise and pulling out.

12. Reinstall new valve body with new packing. TORQUE VALVE BODY TO 55-65 INCH POUNDS.13. Install magnetic drain plug. TORQUE PLUG TO 35-45 INCH POUNDS. Using nonelectrical wire, WP 2012 00, Item 357, lockwire plug to valve body.14. Remove oil cooler compartment access doors (WP 0316 00).

15. Remove transmission covers (WP 0310 00).

16. Remove both left and right air inlet fairings (WP 0309 00).

17. Disconnect engine output shaft from input module flange (WP 0495 00).

18. Disconnect forward engine support tube from gimbal on input module (WP 0495 00).

19. Disconnect hydraulic pressure line and hydraulic return line at quick-disconnects ( Figure 2, Detail A).

nnect Lines and Wiring

20. Disconnect electrical connector, P447, No. 1 or P432, No. 2 from pump modules.

21. Disconnect seal drain from seal drain elbow.

22. Disconnect bleed valve drain line from bleed valve.

23. Unclamp generator leads from generator.

24. Remove screws and slide terminal cover back from generator terminals, or pull rubber nipples back from terminals, as required, to expose terminal connections

(Figure 2, Detail C).

25. Remove nuts and washers holding generator leads to terminals. Remove and tag leads.

26. Disconnect electrical connectors, P251 and P278 from No. 1 or P250 and P277 from No. 2 generator ( Figure 2, Detail A).

27. If t erminal cover was installed, pull wires through cover and remove cover.

28. Disconnect main transmission harness electrical connectors (P400 right side/P401 left side) from brackets under forward engine supports (Figure 2, Detail B).

29. Disconnect engine control cable supports, and clip from accessory modules. Keep bolts, washers, and nuts with supports ( Figure 2, Detail A).

30. Disconnect collective bias tube rod ends from mixer (WP 0515 00). Reposition cables away from main transmission components.

31. Remove bleed-air tube (WP 1285 00).

32. Remove section I tail rotor drive shaft (WP 0677 00).

33. Remove gust lock lever at rear end of main gear box ( WP 0647 00) (Figure 3, Detail A).

34. Place a 1 quart container under oil line to catch fluid trapped in lines.

35. Disconnect oil cooler lines from main transmission. Cap or plug all lines and fittings (WP 0688 00).

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nt. . . . . .: TM 1-1520-237-23 - [WP 0640 00] - 30 JULY 2010, MAIN TRANSMISSION

title . . . .: REMOVAL [2 of 6]

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nnect Oil Lines from Transmission

36. Unclamp oil drain line. Disconnect oil drain line from scupper ( Figure 3, Detail B).

Damage to maintenance crane and helicopter will occur if maintenance crane is used to remove main transmission with main rotor head and swashplate installed.Use sling and overhead hoist to remove main transmission with main rotor head and swashplate installed.

Damage to main rotor head components will result if sling is not properly installed. Make sure sling is not put around damper, damper reservoir, or other parts ofrotor head, other than main rotor head hub arms.

Caution

37. Remove main transmission with main rotor head installed as follows:

a. Put sling straps around hub arms in four places ( Figure 4).

b. Attach sling to hoist with enough capacity to lift main tr ansmission and main rotor head.

c. Adjust sling straps before lifting, f or even distribution of weight.

UH-60L Damage to sling will result if sling contacts studs on tail takeoff housing. Studs will cut into sling. Make sure sling does not contact studs.

Caution

38. Remove main transmission with main rotor head and swashplate removed as follows:

a. Attach sling straps to input modules and around tail takeoff housing (Figure 4).

b. Attach sling to maintenance crane or a hoist with enough capacity to lift main transmission.

c. Adjust sling straps before lifting, f or even distribution of weight.

CS IThe upper wall perimeter of the main transmission module housing is a critical area of the transmission. These surfaces must not be damaged during and after

removal of the transmission. Use extreme caution when removing transmission and provide protective covering to these surfaces during removal or installation.

Warning

39. Remove bolts connecting control rods to primary servos. Press in on hole in bolthead to release retaining balls so bolts can be removed.

Sling

CS IUpper and lower ends of tie r od at rear bellcrank support are critical characteristic surfaces which must not be damaged during and after r emoval of main transmission.

Use extreme caution when removing or disconnecting and provide protective covering after removal.

Warning

40. Remove bolt, washers, and nut from lower end of aft t ie rod (Figure 5).

41. Swing aft t ie rod out. Remove bolts and washers securing support fitting to deck. Remove shims.

42. Temporarily install bolt, washers, and nut on lower end of aft tie rod through support fitting.

43. Remove aft bellcrank support mounting bolts and spacers from support legs on transmission deck.

44. Remove bolts and washers securing forward bellcrank support t o airframe.

45. Remove main transmission mounting bolts. Locally make mounting bolt adapter tool ( WP 2014 00, Figure 46), if necessary, to remove two f ront bolts.

Hoist cable may break, causing injury to personnel or damage to equipment, if hoist is used to free a sticking component being removed from helicopter. Do notuse too much force when removing a component.

Hoist cable may be damaged or broken, causing injury to personnel or damage to equipment if hook is allowed to contact pulley when removing a component fromhelicopter. Do not allow hook assembly to contact pulley

Warning

Damage to helicopter will result if all connections to main transmission are not removed prior to hoisting. Make sure all attaching lines and electrical connections are

removed and area is clear before hoisting.

Caution

Attach guide straps to main transmission. To help guide main transmission clear of helicopter, place assistant on each side of transmission.

Note

46. Hoist main t ransmission clear of helicopter.

ve Bellcrank Supports

47. Lower main transmission onto adapter (Figure 6).

on Adapter

48. Install bolts, w ashers, and nuts holding transmission to adapter.

If transmission is to be r einstalled, removal of components is not r equired.

Note

49. If main t ransmission is to be replaced, remove main rotor head (WP 0556 00).

50. If main t ransmission is to be replaced, remove swashplate (WP 0576 00).

51. If main transmission is to be replaced, disconnect electrical connectors, remove clamp assemblies and lacing tape securing wiring to transmission. Remove

wiring harness. To aid installation, note harness routing and location of clamps (Figure 8, Sheet 1, Figure 8, Sheet 2, Figure 8, Sheet 3 and Figure 8, Sheet 4).