988G Wheel Loader Power Train Caterpillar

Assembly Procedure

Table 1

Required Tools
Tool	Part Number	Part Description	Qty
A	FT-0947	Compressor	2
B	7M-7238	Sleeve	1
C	FT-0833	Clamp	2
D	FT-0834	Nozzle	1

1. Perform the following steps in order to assemble the carrier assembly for the No. 1 clutch.
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   Illustration 1	g00517713

   1. Put clean oil on bearing (1) . Install bearing (1) in planetary gear (2) .

   2. Repeat Step 1.a for the remaining two planetary gears.
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   Illustration 2	g00517714

   3. Place a thrust disc (3) on each side of the planetary gear. Install the thrust discs and the planetary gear in the carrier. Install planetary shaft (4) . The spring pin hole in the planetary shaft must be in alignment with the hole in the carrier.

   4. Repeat Step 1.c for the remaining two planetary gears.
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   Illustration 3	g00517715

   5. Install spring pin (5) that holds planetary shaft (4) in position. Spring pin (5) should be even with the outer surface of the carrier. Repeat for the remaining two shafts.
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   Illustration 4	g00680988

   6. Install ring seal (6) and two ring seals (7) on the carrier.
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   Illustration 5	g00517717

   7. Install ring gear (8) on the carrier.

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Illustration 6	g00517718

2. Install bearing (10) in the No. 1 clutch housing.

   Note: The bearing must be in contact with the counterbore in the clutch housing.

3. Install retaining ring (9) .

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Illustration 7	g00517719

4. Install ring seal (11) and ring seal (12) on clutch piston (13) .

   Note: Install the ring seals so that the oil groove and the sealing edge will be toward the inside of the No. 1 clutch housing.

5. Put clean oil on the seals.

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Illustration 8	g00517720

6. Install clutch piston (13) in No. 1 clutch housing (14) .

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Illustration 9	g00517721

7. Use Tooling (A) in order to hold the clutch piston in the No. 1 clutch housing. Invert the No. 1 clutch housing. The groove in the bearing in the clutch housing must be in alignment with the dowel in the carrier. Install the retaining ring that holds the clutch housing to the carrier.

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Illustration 10	g00517722
Typical Example

8. Install six reaction dowels (15) .

9. Put clean oil on four friction discs (16) and on three clutch plates (17) .

10. Install the friction discs and the clutch plates in alternating order. Start with a friction disc and end with a friction disc.

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Illustration 11	g00517757
Typical Example

11. Install plate assembly (18) . The oil passage in the plate assembly must align with the oil passage in the No. 1 clutch housing.

12. Perform the following steps in order to assemble the No. 2 clutch.
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    Illustration 12	g00517759

    1. Install bearing (21) in the carrier. The groove must be facing upward.

    2. Install retaining ring (19) that holds the bearing in position.
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    Illustration 13	g00517760

    3. Put clean oil on bearing (22) . Install bearing (22) in planetary gear (23) . Repeat this procedure for the remaining two planetary gears.
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    Illustration 14	g00517761

    4. Place a thrust disc (25) on each side of the planetary gear. Install the planetary gears and thrust discs in the carrier.

    5. Install planetary shaft (24) in the carrier. The spring pin hole in the planetary shaft must align with the hole in the carrier.

    6. Install spring pin (26) . The outer edge of the spring pin should be even with the outer edge of the carrier.

    7. Repeat Step 12.d through Step 12.f for the remaining two sets of planetary gears.
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    Illustration 15	g00517763

    8. Install retaining ring (29) on carrier (27) . Place carrier (27) in position on ring gear (28) . Compress retaining ring (29) with screwdrivers. Slide the carrier into the ring gear. Remove the screwdrivers. Retaining ring (29) must be engaged in the groove in the ring gear.

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Illustration 16	g00517764

13. Install bearing (32) on the input shaft.

    Note: The notch in the bearing must be aligned with the dowel in the input shaft.

14. Install spacer (31) .

15. Install retaining ring (30) that holds the spacer and the bearing in position.

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Illustration 17	g00517765

16. Heat carrier (33) to a temperature of 149 °C (300 °F).

17. Install the carrier on the output shaft.

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Illustration 18	g00517766

18. Install bearing (34) in the output shaft.

    Note: The bearing must make contact with the counterbore in the shaft.

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Illustration 19	g00517767

19. Slide input shaft (35) in output shaft (37) .

20. Install retaining ring (36) .

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Illustration 20	g00517768

21. Install sun gear (39) in the input shaft.

22. Install two ring seals (38) on the carrier. Put clean oil on the ring seals.

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Illustration 21	g00517968

23. Attach a suitable hoist and suitable lifting chains.

24. Use the hoist in order to install the shaft assembly in the carrier assembly for the No. 2 clutch assembly.

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Illustration 22	g00517970

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Illustration 23	g02533665

25. Install sun gear (41) on the input shaft.

    Note: Install sun gear (41) with the longer end of the flange toward the bearing on the shaft.

    Note: The slots of the spacer should face away from the sun gear. Refer to illustration 23.

26. Install spacer (40) .

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Illustration 24	g00517971

27. Use Tooling (B) , bolt (43) , and retainer plate (42) in order to hold the carrier assembly on the shaft assembly.

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Illustration 25	g00517972

28. Attach a suitable hoist and lifting chains.

29. Use the hoist in order to install the carrier assembly and the shaft assembly in the No. 1 clutch housing.

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Illustration 26	g00680979

30. Install ring gear (44) on the carrier assembly for the No. 2 clutch housing.

31. Put clean oil on friction discs (46) and clutch plates (47) .

32. Install the four friction discs and the three clutch plates in alternating order. Start with a friction disc and end with a friction disc.

33. Install 12 springs (45) .

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Illustration 27	g00517974

34. Install ring seal (48) on the carrier assembly for the No. 2 clutch housing. Put clean oil on the ring seal.

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Illustration 28	g00517975

35. Install the two ring seals on clutch piston (49) . Install the ring seals so that the oil groove and the sealing edge will be facing toward the inside of the No. 2 clutch housing.

36. Put clean oil on the ring seals.

37. Install clutch piston (49) in No. 2 clutch housing (50) .

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Illustration 29	g00517997

38. Use Tooling (A) in order to hold the clutch piston in the No. 2 clutch housing.

39. Attach a suitable hoist and lifting chains.

40. Use the hoist in order to install the clutch housing in position on the dowels, the springs, and the plate assembly.

41. The alignment mark on the No. 1 clutch housing must be in alignment with the mark on the No. 2 clutch housing. The 12 springs must be in the bores of the clutch piston for the No. 2 clutch housing.

42. Remove Tooling (A) .

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Illustration 30	g00518000

43. Install sun gear (51) .

44. Perform the following steps in order to assemble the carrier for the No. 2 clutch gear.
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    Illustration 31	g00518132

    1. Install bearing (53) in the carrier. Install retaining ring (52) that holds the bearing.
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    Illustration 32	g00518133

    2. Put clean oil on bearing (54) . Install bearing (54) in planetary gear (55) .

    3. Place a thrust disc (56) on each side of the planetary gear. Place the thrust discs and the planetary gear in position in the carrier.
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    Illustration 33	g00518134

    4. Install planetary shaft (57) that holds the planetary gear in position. The hole in the planetary shaft for the spring pin must align with the hole in the carrier.

    5. Use a hammer and a punch in order to install spring pin (58) . The end of the spring pin must be flush with the outer surface of the carrier.

    6. Repeat Step 44.b through Step 44.e for the remaining two planetary gears.

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Illustration 34	g00518135

45. Place hub assembly (59) in position on the carrier. The dowel in the hub assembly must engage the notch in the bearing.

46. Install the retaining ring that holds the hub assembly in position.

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Illustration 35	g00518136

47. Install ring (60) on the carrier.

48. Attach a suitable hoist and lifting chains.

49. Use the hoist in order to lower the carrier into ring gear (61) .

50. Use screwdrivers in order to compress ring (60) .

51. Lower the carrier into the ring gear. Verify that ring (60) is engaged in the groove in the ring gear.

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Illustration 36	g00518137

52. Attach a suitable hoist and lifting chains.

53. Use the hoist in order to install the carrier assembly onto the No. 2 clutch housing.

54. Install the retaining ring that holds the carrier assembly in position.

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Illustration 37	g00518138

55. Install reaction dowels (64) .

56. Put clean oil on three friction discs (62) and two clutch plates (63) .

57. Install the three friction discs and the two clutch plates in alternating order. Start with a friction disc and end with a friction disc.

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Illustration 38	g00518140

58. Install the two ring seals on clutch piston (65) . Install the ring seals so that the oil groove and the sealing edge will be facing toward the inside of the No. 3 clutch housing.

59. Put clean oil on the ring seals.

60. Install clutch piston (65) in No. 3 clutch housing (66) .

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Illustration 39	g00518238

61. Use Tooling (C) in order to hold the clutch piston in the No. 3 clutch housing.

62. Install 12 springs (67) in the No. 3 clutch housing.

63. Attach a suitable hoist and lifting chains.

64. Use the hoist in order to install the No. 3 clutch housing on the No. 2 clutch housing.

65. Align the mark on the No. 3 clutch housing with the mark on the No. 2 clutch housing. The 12 springs must be in the bores of the clutch piston on the No. 3 clutch housing.

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Illustration 40	g00518239

66. Install ring gear (68) .

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Illustration 41	g00518240

67. Put clean oil on five friction discs (69) and four clutch plates (70) .

68. Install the five friction discs and four clutch plates over the hub in an alternating order. Start with a friction disc and end with a friction disc.

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Illustration 42	g00518242

69. Install housing assembly (71) over the friction discs and the clutch plates.

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Illustration 43	g00518244

70. Heat carrier (72) to a maximum temperature of 149 °C (300 °F). Install the carrier on housing (73) .

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Illustration 44	g00518248

71. Install two ring seals (75) on clutch piston (74) . Install the ring seals so that the oil groove and the sealing edge will be facing toward the inside of housing (73) .

72. Put clean oil on the ring seals.

73. Install clutch piston (74) in housing (73) .

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Illustration 45	g00518249

74. Perform the following steps in order to install three disc springs (78) .

    1. Install the first disc spring with the outside diameter of the spring in contact with the housing assembly.

    2. Install the next two disc springs with the outside diameter of the springs in contact with each other.

75. Place retainer plate (77) in position on the housing.

76. Use a suitable press and suitable bar stock in order to put the disc springs under compression.

77. Install retaining ring (76) .

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Illustration 46	g00518250

78. Install two ring seals (79) on the carrier assembly. Put clean oil on the ring seals.

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Illustration 47	g00518251

79. Attach a suitable hoist and lifting chains.

80. Use the hoist in order to install carrier assembly (73) in position in housing (71) .

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Illustration 48	g00518252

81. Install 20 bolts (80) and the washers.

82. Install retaining ring (81) .

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Illustration 49	g00518254

83. Put clean oil on two friction discs (82) and one clutch plate (83) .

84. Install the two friction discs and one clutch plate in alternating order. Start with a friction disc and end with a friction disc.

85. Install 12 springs (84) .

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Illustration 50	g00518255

86. Install the two ring seals (86) on clutch piston (87) . Install the ring seals so that the oil groove and the sealing edge will be facing toward the inside of No. 4 clutch housing.

87. Install clean oil on the ring seals.

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Illustration 51	g00518256

88. Install clutch piston (87) in No. 4 clutch housing (85) .

89. Install the two 330 mm (13 inch) bolts that hold the clutch housings together. Tighten the bolts to a torque of 115 ± 7 N·m (85 ± 5 lb ft).

90. Use Tooling (C) to hold the clutch piston in the No. 4 clutch housing.

91. Attach a suitable hoist and lifting chains.

92. Use the hoist in order to install the clutch housing in position on the No. 3 clutch housing.

    Note: The mark on the No. 4 clutch housing must be in alignment with the No. 3 clutch housing. The 12 springs must be in the bore of the clutch piston in the No. 4 clutch housing.

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Illustration 52	g00518277

93. Install bearing (89) in the manifold assembly.

    Note: The notch on the inner race must be facing downward. The bearing must make contact with the counterbore in the manifold assembly. Install retaining ring (88) .

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Illustration 53	g00518404

94. Install O-ring seal (90) and O-ring seal (91) in the manifold assembly. Put clean oil on the O-ring seals.

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Illustration 54	g00518405

95. Attach a suitable hoist and lifting chains.

96. Use the hoist in order to install the manifold assembly in position on the No. 4 clutch housing.

    Note: The notch in the bearing must align with the dowel in the shaft assembly.

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Illustration 55	g00518406

97. Rotate the No. 5 clutch housing until two of the bolts are in alignment with slots (95) in the manifold assembly.

98. Remove the two bolts.

99. Install two threaded rods (93) in the bolt holes. The rods should have a 3/8" - 16 NC thread. The rods should be 203 mm (8 inch) long. Install two large, flat washers and two nuts.

100. Install sun gear (96) .

101. Tighten the nuts evenly on threaded rods (93) until retaining ring (94) can be installed.

102. Install retaining ring (94) . Remove the threaded rods and install the two original bolts.

103. Perform the following steps in order to assemble the carrier assembly.
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     Illustration 56	g00518408

     1. Put clean oil on bearings (97) . Install two bearings (97) in planetary gear (98) .
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     Illustration 57	g00518410

     2. Place a thrust disc (99) on each side of the planetary gear. Place the planetary gear and the thrust discs in the carrier.
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     Illustration 58	g00518411

     3. Install planetary shaft (100) in the carrier. The spring pin hole in the planetary shaft must align with the hole in the carrier.

     4. Install spring pin (101) . The outer edge of the spring pin should be even with the outer edge of the carrier.

     5. Repeat Step 103.a through Step 103.d for the remaining three planetary gears.

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Illustration 59	g00518412

104. Install the gasket on slinger (102) .

105. Place slinger (102) in position on the carrier assembly.

106. Install the bolts and the locks that hold the slinger in position.

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Illustration 60	g00518413

107. Attach a suitable hoist and lifting chains.

108. Use the hoist in order to install the carrier assembly in position in the transmission.

109. Install spacer (104) and retaining ring (103) .

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Illustration 61	g00518414

110. Install ring gear (106) over the carrier assembly.

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Illustration 62	g00518415

111. Install six reaction dowels (110) in the manifold assembly.

112. Put clean oil on three friction discs (108) and two clutch plates (109) .

113. Install the three friction discs and the two clutch plates in alternating order. Start with a friction disc and end with a friction disc. Align notches (107) with dowels (110) as clutch plates (109) are being installed.

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Illustration 63	g00518416

114. Install the two ring seals (113) on clutch piston (112) . Install the ring seals so that the oil groove and the sealing edge will be facing toward the inside of No. 6 clutch housing.

115. Put clean oil on the ring seals.

116. Install clutch piston (112) in No. 6 clutch housing (111) .

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Illustration 64	g00518417

117. Install 12 springs (114) in the manifold assembly.

118. Use Tooling (C) in order to hold the clutch piston in the No. 6 clutch housing.

119. Attach a suitable hoist and lifting chains.

120. Use the hoist in order to install the clutch housing on the manifold assembly. The mark on the clutch housing must be aligned with the mark on the manifold assembly. The 12 springs must be in the bores in the clutch piston of the No. 6 clutch housing.

121. Install the 18 bolts that hold the clutch housings together. Tighten the bolts to a torque of 115 ± 7 N·m (85 ± 5 lb ft).

122. Perform the following steps in order to verify that the clutch pistons are free in the clutch housings.
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     Illustration 65	g00518418

     1. Use Tooling (D) in order to pressurize each of the five oil passages. The air pressure should be 690 kPa (100 psi) to 1035 kPa (150 psi).

     2. Each clutch piston should have a travel of 3.0 mm (.12 inch) to 6.4 mm (.25 inch).

     3. If the clutch pistons do not move the correct distance, place a small amount of clean oil in the passage. Repeat Step 122.a. The transmission must be disassembled if the pistons do not move. The clutch pistons and the ring seals must be checked.

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Illustration 66	g00518419

123. Attach a suitable hoist and lifting chains.

124. Use the hoist in order to place the transmission case on suitable wood blocks.

125. Lower the planetary assembly into the transmission case. The dowel in the manifold assembly must be aligned with the hole in the transmission case.

126. Install the two bolts and the washers that hold the planetary assembly to the transmission case.

127. Remove the bolt, the washer, and Tooling (B) from the shaft assembly.

     Note: This Tooling was installed in Step 27.

128. Place the transmission case in the horizontal position. The opening for the transmission hydraulic control valve should be facing upward.

End By:

1. Install the transmission hydraulic control relief valve. Refer to Disassembly and Assembly, "Relief Valve (Transmission Hydraulic Control Valve) - Install" for the machine that is being serviced.
2. Install the transfer gears. Refer to Disassembly and Assembly Manual, "Transmission to Input Transfer Gears and Output Transfer Gears - Connect" for the machine that is being serviced.