988G Wheel Loader Power Train Caterpillar

Assembly Procedure

Note: Cleanliness is an important factor. Before assembly, all parts should be thoroughly cleaned in cleaning fluid. Allow the parts to air dry. Wiping cloths or rags should not be used to dry parts. Lint may be deposited on the parts which may cause later trouble. Inspect all parts. If any parts are worn or damaged, use new parts for replacement.

Note: Apply oil to all of the bearings before assembly.

1. Check the condition of the O-ring seals that are used in the torque converter and torque converter housing. If any of the seals are damaged, use new parts for replacement.
   Show/hide table

   Illustration 1	g00674989

2. Install five O-ring seals (96) and three plugs (97).
   Show/hide table

   Illustration 2	g00674987

3. Install block (95) and four bolts (94).
   Show/hide table

   Illustration 3	g00674986

4. Install ring (93) and two bearings (92) to idler gear assembly (91).
   Show/hide table

   Illustration 4	g00675821

5. Install idler gear assembly (91).
   Show/hide table

   Illustration 5	g00675822

6. Install idler gear shaft (90).

7. Install bolt (89) and the washer.
   Show/hide table

   Illustration 6	g00674982

8. Install O-ring seal (88) to cover (87).
   Show/hide table

   Illustration 7	g00675823

9. Install three bolts (86) and cover 87.
   Show/hide table

   Illustration 8	g00675717

10. Use the proper equipment to handle bearing cup (85).

11. Lower the temperature of bearing cup (85).

12. Install bearing cup (85) into the housing.
    Show/hide table

    Illustration 9	g00675718

13. Use the proper equipment to handle bearing (83).

14. Heat bearing (83) to a maximum temperature of 135 °C (275 °F).

15. Install bearing (83) onto gear assembly (77).
    Show/hide table

    Illustration 10	g00674959

16. Install plate (82) onto adapter (80).

17. Install retaining ring (81).
    Show/hide table

    Illustration 11	g00674957

18. Install adapter assembly (80) into gear assembly (77).

19. Install retaining ring (79).
    Show/hide table

    Illustration 12	g00675719

20. Use the proper equipment to handle bearing (78).

21. Heat bearing (78) to a maximum temperature of 135 °C (275 °F).

22. Install bearing (78) onto gear assembly (77).

    Note: Allow the bearing and the gear assembly to reach a uniform temperature.

23. Use a hammer and a suitable punch to reset the bearing around the inside race of the bearing. This will ensure that the bearing is seated correctly.
    Show/hide table

    Illustration 13	g00675721

24. Install gear assembly (77) and entire shim pack (84).

25. If both pump drives were removed, repeat Steps 10 through 24 for the remaining pump drive.
    Show/hide table

    Illustration 14	g00716568

26. Lower temperature of bearing cup (75). Install bearing cup (75) into adapter (73). Ensure that the bearing cup (75) is seated.
    Show/hide table

    Illustration 15	g00716572

    Note: DO NOT install the seals to the adapters at this time.

27. Use two persons to install adapters (73) and (77) on the torque converter housing. The weight of adapter (73) is 30 kg (65 lb).

28. Install seven bolts (72) and six bolts (78). The torque for bolts (72) and (78) is 240 ± 40 N·m (177 ± 30 lb ft).

29. When possible, rotate either the torque converter or the outer housing to ensure that the bearings are properly seated.
    Show/hide table

    Illustration 16	g00675824

30. Use Tooling (F) to check bearing end play. The bearing end play must be 0.15 ± 0.05 mm (.006 ± .002 inch). Remove shims (84) to attain the correct bearing end play.

31. Remove the pump adapters from the torque converter housing.
    Show/hide table

    Illustration 17	g00674954

32. Use Tooling (B) to install seal (76) into adapter (73).

33. Lightly lubricate seal (76) with oil.
    Show/hide table

    Illustration 18	g00674953

34. Install two O-ring seals (74) on adapter (73).

35. Lubricate the O-ring seals (74) prior to assembly.

36. Install two O-ring seals and one lip seal on the remaining adapter.
    Show/hide table

    Illustration 19	g00716572

37. Install the correct amount of shims (84) to the torque converter housing. The correct shim thickness was determined in the above steps.

38. Use two persons to install adapters (73) and (77) on the torque converter housing. The weight of adapter (73) is 30 kg (65 lb).

39. Install seven bolts (72) and six bolts (78). The torque for bolts (72) and (78) is 240 ± 40 N·m (177 ± 30 lb ft).

40. When possible, rotate either the torque converter or the outer housing to ensure that the bearings are properly seated.

41. Use Tooling (F) to recheck the bearing end play. If necessary, repeat the above procedure.
    Show/hide table

    Illustration 20	g00674791

42. Install seal (71) onto piston (70).
    Show/hide table

    Illustration 21	g00674790

43. Install piston (70).
    Show/hide table

    Illustration 22	g00674788

    Show/hide table

    Illustration 23	g00674750

44. Install two wear plates (68) and two friction discs (69).
    Show/hide table

    Illustration 24	g00674748

45. Install plate (67) and retaining ring (66).
    Show/hide table

    Illustration 25	g00674744

    Show/hide table

    Illustration 26	g00674747

46. Install clutch adapter (65) and hub (63) to turbine (64).

47. Install 24 bolts (62). The torque for bolts (62) is 105 ± 15 N·m (77 ± 11 lb ft).
    Show/hide table

    Illustration 27	g00674727

48. Install bearing (61).
    Show/hide table

    Illustration 28	g00674725

49. Install O-ring seal (59) and two plugs (60).
    Show/hide table

    Illustration 29	g00675696

50. Use the appropriate equipment to turn the housing assembly onto the opposite side, as shown.

51. Install turbine assembly (64) into housing assembly.
    Show/hide table

    Illustration 30	g00675769

52. Install the ring and the plate below bearing (58).

53. Install bearing (58).
    Show/hide table

    Illustration 31	g00675437

54. Use the proper equipment to handle bearing (57).

55. Heat bearing (57) to a maximum temperature of 135 °C (275 °F).

56. Install bearing (57) onto the outer shaft.

    Note: Allow the bearing and the shaft to reach a uniform temperature.

57. Use a hammer and a punch to reset the bearing around the inside race of the bearing. This will ensure that the bearing is seated correctly.

58. Use the proper equipment to handle seal carrier (56).

    Note: Allow the ring and the shaft to reach a uniform temperature.

59. Heat seal carrier (56) to a maximum temperature of 135 °C (275 °F).

60. Install seal carrier (56) onto the outer shaft.
    Show/hide table

    Illustration 32	g00675571

61. Use a hammer and a suitable punch to install pin (55).
    Show/hide table

    Illustration 33	g00674523

62. Install seal (52).

63. Install two seals (53).

64. Install retaining ring (54).
    Show/hide table

    Illustration 34	g00674522

65. Install seal (51) to sleeve (50).
    Show/hide table

    Illustration 35	g00674521

66. Install sleeve (50) and eight bolts (49). The torque for bolts (49) is 30 ± 5 N·m (22 ± 4 lb ft).
    Show/hide table

    Illustration 36	g00674520

67. Use the proper equipment to handle race (48).

68. Lower the temperature of race (48).

69. Install race (48) in drive gear (47).
    Show/hide table

    Illustration 37	g00674519

70. Install drive gear (47) onto housing assembly (45).

71. Install 12 bolts (46). The torque for bolts (46) is 105 ± 15 N·m (77 ± 11 lb ft).
    Show/hide table

    Illustration 38	g00674514

72. Install Tooling (E) to housing assembly (45).

73. Attach a suitable hoist and lifting slings to housing assembly (45).

74. Use a suitable lifting device to install housing assembly (45) to outer shaft assembly. The weight of housing assembly (45) is 45 kg (100 lb).
    Show/hide table

    Illustration 39	g00674516

75. Install seal (44) onto piston (43).
    Show/hide table

    Illustration 40	g00674512

76. Install piston (43).
    Show/hide table

    Illustration 41	g00674510

77. Install two friction discs (42) and one wear plate.
    Show/hide table

    Illustration 42	g00674508

78. Install plate (41).

79. Install two bolts (22) on the underside of plate (41).
    Show/hide table

    Illustration 43	g00674506

80. Install 12 bolts (38) and impeller (36) to adapter assembly (39). The torque for bolts (38) is 105 ± 15 N·m (77 ± 11 lb ft).
    Show/hide table

    Illustration 44	g00674505

81. Use the proper equipment to handle race (37).

82. Lower the temperature of race (37).

83. Install race (37) in impeller (36).
    Show/hide table

    Illustration 45	g00674507

84. Install the ring and the plate below bearing (40).

85. Install bearing (40).

86. Install the plate above bearing (40).
    Show/hide table

    Illustration 46	g00674504

87. Use two persons to install the impeller (36) onto the shaft assembly. The weight of impeller (36) is 29 kg (65 lb).
    Show/hide table

    Illustration 47	g00674503

88. Install retaining ring (35).
    Show/hide table

    Illustration 48	g00674501

89. Install the ring and the plate below bearing (34).

90. Install bearing (34).
    Show/hide table

    Illustration 49	g00674499

91. Install spacer (33).
    Show/hide table

    Illustration 50	g00674498

92. Install race (32) and retaining ring (31).

    Note: Inspect the splines on the stator. If the splines were damaged during disassembly, replace the stator with a new part.

    Show/hide table

    Illustration 51	g00675434
    Typical Example

93. Use proper equipment to handle stator (24).

94. Heat stator (24) to a maximum temperature of 121 °C (250 °F) for one hour.

95. Install stator (24) onto cam (30).

96. Install retaining ring (29).
    Show/hide table

    Illustration 52	g00675433

97. Install plate (28) and retaining ring (27) onto stator (24). Repeat this procedure for the opposite side.
    Show/hide table

    Illustration 53	g00673889

98. Install 13 springs (25) and 13 rollers (26).

99. Install springs (25) in the deepest part of the groove. Assemble the springs so that the maximum number of loops face toward the outside of the cam.

100. Install rollers (26) in the narrowest part of the groove.
     Show/hide table

     Illustration 54	g00673888

101. Install stator (24) to carrier assembly (23).
     Show/hide table

     Illustration 55	g00673887

102. Carefully rotate carrier assembly into the upright position. The springs and the rollers will hold the stator in place.

103. Install Tooling (D) to carrier assembly (23).

104. Attach a suitable lifting device and slings to carrier assembly (23).

105. Use a suitable lifting device to install carrier assembly (23) to the torque converter housing. The weight of carrier assembly (23) is 132 kg (290 lb).
     Show/hide table

     Illustration 56	g00673885

106. Install 36 bolts (21). The torque for bolts (21) is 60 ± 7 N·m (45 ± 5 lb ft).
     Show/hide table

     Illustration 57	g06372634

107. Install orifice plug (21A).
     Show/hide table

     Illustration 58	g00675572

108. Use the proper equipment to handle seal carrier (20).

109. Heat seal carrier (20) to a maximum temperature of 135 °C (275 °F).

110. Install seal carrier (20) onto inner shaft (18).

111. Use the proper equipment to handle bearing (19).

112. Heat bearing (19) to a maximum temperature of 135 °C (275 °F).

113. Install bearing (19) onto inner shaft (18).

     Note: Allow the bearing and the shaft to reach a uniform temperature.

114. Use a hammer and a suitable punch to reset the bearing around the inside race of the bearing. This will ensure that the bearing is seated correctly.
     Show/hide table

     Illustration 59	g00673883

115. Install Tooling (C) to shaft assembly (18).

116. Attach a suitable lifting device and a suitable lifting sling to Tooling (C).

117. Use the suitable lifting device to install shaft assembly (18). The weight of shaft assembly (18) is 17 kg (38 lb).
     Show/hide table

     Illustration 60	g00673879

118. Carefully position the torque converter onto the side, as shown.
     Show/hide table

     Illustration 61	g00673881

119. Install washer (17), retainer (16), and two bolts (15). The torque for bolts (15) is 105 ± 15 N·m (77 ± 11 lb ft).
     Show/hide table

     Illustration 62	g00673880

120. Install cover (14) and six bolts (13). The torque for bolts (13) is 60 ± 7 N·m (44 ± 5 lb ft).
     Show/hide table

     Illustration 63	g00660849

121. Position the torque converter upright.

122. Install gasket (10).

123. Install O-ring seals (11) and (12).
     Show/hide table

     Illustration 64	g00660847

124. Use Tooling (B) to install seal (9) into retainer (8).
     Show/hide table

     Illustration 65	g00660846

125. Install retainer (8) and eight bolts (7). The torque for bolts (7) is 60 ± 7 N·m (45 ± 5 lb ft).

     Note: It is necessary to install the torque converter into the torque converter housing prior to installation of the idler gear.

     Show/hide table

     Illustration 66	g00665414

126. Install Tooling (A) to the torque converter housing.

127. Attach a suitable lifting device and lifting chains to Tooling (A), as shown.

128. Use the suitable lifting device to install the torque converter housing to the torque converter. The weight of the torque converter housing is 270 kg (600 lb).
     Show/hide table

     Illustration 67	g00665412

129. Install eleven bolts (6) and the washers.
     Show/hide table

     Illustration 68	g00665121

130. Install yoke (5).

131. Install O-ring seal (4).
     Show/hide table

     Illustration 69	g00665406

132. Install bolt (2) and retainer (3). The torque for bolt (2) is 240 ± 25 N·m (175 ± 20 lb ft).
     Show/hide table

     Illustration 70	g00660841

133. Install speed sensor (1).

End By:

1. Install the transmission oil pump. Refer to Disassembly and Assembly, "Transmission Oil Pump - Install" for the machine that is being serviced.

2. Install the torque converter outlet relief valve. Refer to Disassembly and Assembly, "Relief Valve (Torque Converter Outlet) - Install" for the machine that is being serviced.

3. Install the modulating valve for the torque converter impeller clutch. Refer to Disassembly and Assembly, "Modulating Valve (Torque Converter Impeller Clutch) - Install" for the machine that is being serviced.

4. Install the modulating valve for the torque converter lockup clutch. Refer to Disassembly and Assembly, "Modulating Valve (Torque Converter Lockup Clutch) - Install" for the machine that is being serviced.

5. Install the torque converter. Refer to Disassembly and Assembly, "Torque Converter - Install" for the machine that is being serviced.