770 and 772 Off-Highway Trucks Power Train Transmission Hydraulic Control - Disassemble Caterpillar

Disassembly Procedure

Start By:

1. Remove the transmission hydraulic control. Refer to Disassembly and Assembly, "Transmission Hydraulic Control - Remove".

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Illustration 1	g00572402

1. Remove O-ring seals (1) from manifold assembly (2).

2. Put identification marks on coil assemblies (3) for correct installation. Remove locknuts (4). Remove coil assemblies (3) from the cartridge assemblies.

3. Remove plug (5) and the O-ring seal from the manifold assembly.
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   Illustration 2	g00572408

4. Remove cartridge assemblies (6) from the manifold assembly.
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   Illustration 3	g00572413

5. Remove O-ring seals (7) and backup rings (8) from each of the cartridge assemblies.
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   Illustration 4	g00572416

6. Remove bolts (9), the washers, cover (11), and harness assembly (10) from manifold assembly (2).
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   Illustration 5	g00572417

7. Remove lip seal (12) from manifold assembly (2).
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   Illustration 6	g00572418

8. Position manifold assembly (2) in a suitable press. Use Tooling (A) (not shown) to remove bearing (13) from manifold assembly (2).
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   Illustration 7	g00572421

9. Remove O-ring plugs (15) and the O-ring seals from valve body (14).
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   Illustration 8	g00572423

   Note: Each load piston body is marked according to the clutch that is controlled. The valve body is marked by a letter at Location (X).

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   NOTICE
   Failure to properly assemble parts or failure to follow established procedures can lead to damage of the parts and assembly. To avoid damage to parts, always identify and mark the parts so that they can be installed in the same location. Never force parts during assembly.

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   Illustration 9	g00572601

   Note: The components in station (A) actuate clutch (3). The components in station (B) actuate clutch (1). The components in station (C) actuate clutch (2). The components in station (E) actuate clutch (5). The components in station (F) actuate clutch (4). The components in station (G) actuate clutch (6). The components in station (H) actuate clutch (7).

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   Personal injury can result from being struck by parts propelled by a released spring force. Make sure to wear all necessary protective equipment. Follow the recommended procedure and use all recommended tooling to release the spring force.

10. Remove socket head bolts (31) and the washers. Remove load piston body (29) from the valve body.

11. Remove springs (17) and (18), shims (19), spacer (20), selector piston (22), and load piston (21) from load piston body (29).

12. Remove spring (26), cascade orifice (27), O-ring seal (28), and plugs (30) from load piston body (29).

    Note: Valve Group (H) has two plugs (30).

13. Remove stop (25), spool assembly (24), and spring (16) from the valve body.

14. Remove slug (23) from spool assembly (24).

15. Repeat Steps 10 through 14 for the remaining six stations.
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    Illustration 10	g00572425

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    Personal injury can result from being struck by parts propelled by a released spring force. Make sure to wear all necessary protective equipment. Follow the recommended procedure and use all recommended tooling to release the spring force.

16. Use Tooling (B) in order to remove retaining ring (35) from spool assembly (24).

17. Remove retainer (34), spring (33), and ball (32) from spool assembly (24).
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    Illustration 11	g00572431

18. Remove bolt (37), hard washer (38), and load piston (36) from the valve body.
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    Illustration 12	g00572474

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    Personal injury can result from parts and/or covers under spring pressure. Spring force will be released when covers are removed. Be prepared to hold spring loaded covers as the bolts are loosened.

19. Remove bolts (48). Remove cover (47), reducing spool assembly (42), and spring (39) from the selector and pressure control valve.

20. Remove retaining ring (46), retainer (45), spring (44), and check (43) from reducing spool assembly (42).

21. Remove retaining ring (40) and five spacers (41) from the spool.
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    Illustration 13	g00574313

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    Illustration 14	g00572482

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    Personal injury can result from being struck by parts propelled by a released spring force. Make sure to wear all necessary protective equipment. Follow the recommended procedure and use all recommended tooling to release the spring force.

22. Remove cover (52), spool assembly (50), and spring (49) from the valve body.

23. Remove O-ring seal (51) from cover (52).
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    Illustration 15	g00572486

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    Personal injury can result from being struck by parts propelled by a released spring force. Make sure to wear all necessary protective equipment. Follow the recommended procedure and use all recommended tooling to release the spring force.

24. Remove retaining ring (56) from spool assembly (50) with Tooling (B).

25. Remove seat (55) and the O-ring seal. Remove ball (54) and spring (53).
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    Illustration 16	g00572487

26. Remove bolts (57) and the hard washers. Remove rotary actuator (58) from the selector and pressure control valve.
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    Illustration 17	g00572490

27. Remove bolts (59) and cover assembly (60) from rotary actuator (58).
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    Illustration 18	g00572514

28. Position cover assembly (60) in a suitable press. Use Tooling (A) (not shown) to remove roller bearing (61) from cover assembly (60).
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    Illustration 19	g00572518

29. Remove actuator rotor assembly (62) from the actuator body.
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    Illustration 20	g00572520

30. Remove bolts (63) and actuator vane (64).
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    Illustration 21	g00572524

31. Remove O-ring plug assemblies (65) and (66) from the actuator body. Remove the exhaust valve assembly that is under each plug.

32. Position the actuator body in a suitable press. Use Tooling (A) (not shown) to remove roller bearing (67) from the actuator body.
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    Illustration 22	g00572532

33. Remove locating bolts (68). Remove retainers (71) and spring assemblies (69).

34. Remove locking bolt (72) and rotary spool assembly (70).
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    Illustration 23	g01412372

35. Remove spring pin (76), detent cam (74), screen filter (73), and the O-ring seal from rotary spool assembly (70). Remove spring pin (75) from spring pin (76).
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    Illustration 24	g00572558

    Note: Mark the location of Holes (Y) for installation purposes.

36. Remove pin (77) and pin (78) from rotary spool assembly (70).
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    Illustration 25	g00572559

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    Personal injury can result from parts and/or covers under spring pressure. Spring force will be released when covers are removed. Be prepared to hold spring loaded covers as the bolts are loosened.

37. Remove bolts (81), the hard washers, and spring support assembly (79). Remove dowels (80) from spring support assembly (79), if necessary.
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    Illustration 26	g00572562

38. Remove spool assembly (82) and spring (84) from the selector and pressure control valve.

39. Remove spacers (83) from spool assembly (82).
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    Illustration 27	g00572564

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    Personal injury can result from being struck by parts propelled by a released spring force. Make sure to wear all necessary protective equipment. Follow the recommended procedure and use all recommended tooling to release the spring force.

40. Use Tooling (B) (not shown) to remove retaining ring (85) from spool assembly (82).

41. Remove slug (86), spring (87), and ball (88) from spool assembly (82).
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    Illustration 28	g00572566

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    Personal injury can result from parts and/or covers under spring pressure. Spring force will be released when covers are removed. Be prepared to hold spring loaded covers as the bolts are loosened.

42. Remove cap (93), spring (91), spacer (92), and valve (90) from the valve body.

43. Remove body (89) and the O-ring seal from the selector and pressure control valve.