Caterpillar Cat 988K Wheel Loader (Prefix T8E) Service Repair Manual (T8E00001 and up)

1
Service Repair Manual
Models 988K Wheel Loader
2
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Product WHEEL LOADER Model 988K WHEEL LOADER
T8E Configuration 988K Wheel Loader T8E00001-UP
(MACHINE) POWERED BY C18 Engine Disassembly and
Assembly 836K Landfill Compactor, 834K Wheel
Dozer and 988K Wheel Loader Power Train Media
Number -KENR6490-06 Publication Date
-01/09/2015 Date Updated -05/12/2017
i02719081
Torque Converter (Lockup) - Assemble SMCS -
3101-016-L7 Assembly Procedure Table 1
Required Tools Required Tools Required Tools Required Tools
Tool Part Number Part Description Qty
A 138-7573 Link Bracket 1
A 138-7575 Link Bracket 2
B 1P-0520 Driver Gp 1
C 188-1456 Metric Eyebolt 1
D 138-7575 Link Bracket 2
E 138-7575 Link Bracket 3
F 1P-0520 Driver Gp 1
F 8T-5096 Dial Indicator Gp 1
G 1P-1863 Retaining Ring Pliers 1
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.
3
Illustration 1 g00674989 2. Install five O-ring
seals (96) and three plugs (97).
Illustration 2
g00674987
3. Install block (95) and four bolts (94).
Illustration 3 g00674986 4. Install ring (93)
and two bearings (92) to idler gear assembly (91).
4
Illustration 4
g00675821
5. Install idler gear assembly (91).
Illustration 5
g00675822

1. Install idler gear shaft (90).
2. Install bolt (89) and the washer.

Illustration 6
g00674982
8. Install O-ring seal (88) to cover (87).
5
Illustration 7
g00675823
9. Install three bolts (86) and cover 87.

• Illustration 8 g00675717
• Use the proper equipment in order to handle
  bearing cup (85).
• Lower the temperature of bearing cup (85).
• Install bearing cup (85) into the housing.

Illustration 9 g00675718 13. Use the proper
equipment to handle bearing (83).
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1. Heat bearing (83) to a maximum temperature of 135
   C (275 F).
2. Install bearing (83) onto gear assembly (77).

Illustration 10
g00674959

1. Install plate (82) onto adapter (80).
2. Install retaining ring (81).

• Illustration 11 g00674957
• Install adapter assembly (80) into gear assembly
  (77).
• Install retaining ring (79).

8

• Illustration 12 g00675719
• Use the proper equipment in order to handle
  bearing (78).
• Heat bearing (78) to a maximum temperature of 135
  C (275 F).
• Install bearing (78) onto gear assembly (77).
• Note Allow the bearing and the gear assembly to
  reach a uniform temperature.
• Use a hammer and a suitable punch in order to
  reset the bearing around the inside race of the
  bearing. This will ensure that the bearing is
  seated correctly.

• Illustration 13 g00675721
• Install gear assembly (77) and entire shim pack
  (84).
• If both pump drives were removed, repeat Steps 10
  through 24 for the remaining pump drive.

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.
9

• Illustration 15 g00716572
• Note DO NOT install the seals to the adapters at
  this time.
• Use two persons in order to install adapters (73)
  and (77) on the torque converter housing. The
  weight of adapter (73) is 30 kg (65 lb).
• Install seven bolts (72) and six bolts (78). The
  torque for bolts (72) and (78) is 240 40 Nm
  (177 30 lb ft).
• When possible, rotate either the torque converter
  or the outer housing in order to ensure that the
  bearings are properly seated.

Illustration 16 g00675824 30. Use Tooling (F) in
order to check bearing end play. The bearing end
play must be 0.15 0.05 mm (.006 .002 inch).
Remove shims (84) in order to attain the correct
bearing end play. 31. Remove the pump adapters
from the torque converter housing.
10

• Illustration 17 g00674954
• Use Tooling (B) in order to install seal (76)
  into adapter (73).
• Lightly lubricate seal (76) with oil.

• Illustration 18 g00674953
• Install two O-ring seals (74) on adapter (73).
• Lubricate the O-ring seals (74) prior to
  assembly.
• Install two O-ring seals and one lip seal on the
  remaining adapter.

Illustration 19
g00716572
11

1. Install the correct amount of shims (84) to the
   torque converter housing. The correct shim
   thickness was determined in the above steps.
2. Use two persons in order to install adapters (73)
   and (77) on the torque converter housing. The
   weight of adapter (73) is 30 kg (65 lb).
3. Install seven bolts (72) and six bolts (78). The
   torque for bolts (72) and (78) is 240 40 Nm
   (177 30 lb ft).
4. When possible, rotate either the torque converter
   or the outer housing in order to ensure that the
   bearings are properly seated.
5. Use Tooling (F) in order to recheck the bearing
   end play. If necessary, repeat the above
   procedure.

Illustration 20
g00674791
42. Install seal (71) onto piston (70).
Illustration 21
g00674790
43. Install piston (70).
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Illustration 22
g00674788
Illustration 23 g00674750 44. Install two wear
plates (68) and two friction discs (69).
Illustration 24
g00674748
45. Install plate (67) and retaining ring (66).
13
Illustration 25
g00674744

• Illustration 26 g00674747
• Install clutch adapter (65) and hub (63) to
  turbine (64).
• Install 24 bolts (62). The torque for bolts (62)
  is 105 15 Nm (77 11 lb ft).

Illustration 27
g00674727
48. Install bearing (61).
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Illustration 28 g00674725 49. Install O-ring
seal (59) and two plugs (60).

• Illustration 29 g00675696
• Use the appropriate equipment in order to turn
  the housing assembly onto the opposite side, as
  shown.
• Install turbine assembly (64) into housing
  assembly.

Illustration 30 g00675769 52. Install the ring
and the plate below bearing (58).
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53. Install bearing (58).

• Illustration 31 g00675437
• Use the proper equipment in order to handle
  bearing (57).
• Heat bearing (57) to a maximum temperature of 135
  C (275 F).
• Install bearing (57) onto the outer shaft.
• Note Allow the bearing and the shaft to reach a
  uniform temperature.
• Use a hammer and a punch in order to reset the
  bearing around the inside race of the bearing.
  This will ensure that the bearing is seated
  correctly.
• Use the proper equipment in order to handle seal
  carrier (56).
• Note Allow the ring and the shaft to reach a
  uniform temperature.
• Heat seal carrier (56) to a maximum temperature
  of 135 C (275 F).
• Install seal carrier (56) onto the outer shaft.

Illustration 32 g00675571 61. Use a hammer and a
suitable punch in order to install pin (55).
16
Illustration 33
g00674523

1. Install seal (52).
2. Install two seals (53).
3. Install retaining ring (54).

Illustration 34
g00674522
65. Install seal (51) to sleeve (50).
Illustration 35 g00674521 66. Install sleeve
(50) and eight bolts (49). The torque for bolts
(49) is 30 5 Nm (22 4 lb ft).
17

• Illustration 36 g00674520
• Use the proper equipment to handle race (48).
• Lower the temperature of race (48).
• Install race (48) in drive gear (47).

• Illustration 37 g00674519
• Install drive gear (47) onto housing assembly
  (45).
• Install 12 bolts (46). The torque for bolts (46)
  is 105 15 Nm (77 11 lb ft).

18

• Illustration 38 g00674514
• Install Tooling (E) in order to housing assembly
  (45).
• Attach a suitable hoist and lifting slings to
  housing assembly (45).
• Use a suitable lifting device in order to install
  housing assembly (45) to outer shaft assembly.
  The weight of housing assembly (45) is 45 kg (100
  lb).

Illustration 39
g00674516
75. Install seal (44) onto piston (43).
Illustration 40
g00674512
76. Install piston (43).
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Illustration 41 g00674510 77. Install two
friction discs (42) and one wear plate.
Illustration 42
g00674508

1. Install plate (41).
2. Install two bolts (22) on the underside of plate
   (41).

Illustration 43 g00674506 80. Install 12 bolts
(38) and impeller (36) to adapter assembly (39).
The torque for bolts (38) is 105 15 Nm (77
11 lb ft).
20

• Illustration 44 g00674505
• Use the proper equipment in order to handle race
  (37).
• Lower the temperature of race (37).
• Install race (37) in impeller (36).

• Illustration 45 g00674507
• Install the ring and the plate below bearing
  (40).
• Install bearing (40).
• Install the plate above bearing (40).

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Illustration 46 g00674504 87. Use two persons in
order to install the impeller (36) onto the shaft
assembly. The weight of impeller (36) is 29 kg
(65 lb).
Illustration 47
g00674503
88. Install retaining ring (35).

• Illustration 48 g00674501
• Install the ring and the plate below bearing
  (34).
• Install bearing (34).

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Illustration 49
g00674499
91. Install spacer (33).
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.
Illustration 51 Typical Example
g00675434

1. Use proper equipment in order to handle stator
   (24).
2. Heat stator (24) to a maximum temperature of 121
   C (250 F) for one hour.
3. Install stator (24) onto cam (30).
4. Install retaining ring (29).

23
Illustration 52 g00675433 97. Install plate (28)
and retaining ring (27) onto stator (24). Repeat
this procedure for the opposite side.
Illustration 53
g00673889

1. Install 13 springs (25) and 13 rollers (26).
2. 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.
3. Install rollers (26) in the narrowest part of the
   groove.

Illustration 54
g00673888
24
101. Install stator (24) to carrier assembly (23).

• Illustration 55 g00673887
• Carefully rotate carrier assembly into the
  upright position. The springs and the rollers
  will hold the stator in place.
• Install Tooling (D) to carrier assembly (23).
• Attach a suitable lifting device and slings to
  carrier assembly (23).
• Use a suitable lifting device in order to install
  carrier assembly (23) to the torque converter
  housing. The weight of carrier assembly (23) is
  132 kg (290 lb).

Illustration 56 g00673885 106. Install 36 bolts
(21). The torque for bolts (21) is 60 7 Nm (45
5 lb ft).
25

• Illustration 57 g00675572
• Use the proper equipment in order to handle seal
  carrier (20).
• Heat seal carrier (20) to a maximum temperature
  of 135 C (275 F).
• Install seal carrier (20) onto inner shaft (18).
• Use the proper equipment in order to handle
  bearing (19).
• Heat bearing (19) to a maximum temperature of 135
  C (275 F).
• Install bearing (19) onto inner shaft (18).
• Note Allow the bearing and the shaft to reach a
  uniform temperature.
• Use a hammer and a suitable punch in order to
  reset the bearing around the inside race of the
  bearing. This will ensure that the bearing is
  seated correctly.

• Illustration 58 g00673883
• Install Tooling (C) to shaft assembly (18).
• Attach a suitable lifting device and a suitable
  lifting sling to Tooling (C).
• Use the suitable lifting device in order to
  install shaft assembly (18). The weight of shaft
  assembly (18) is 17 kg (38 lb).

26
Illustration 59 g00673879 117. Carefully
position the torque converter onto the side, as
shown.
Illustration 60 g00673881 118. Install washer
(17), retainer (16), and two bolts (15). The
torque for bolts (15) is 105 15 Nm (77 11 lb
ft).
Illustration 61 g00673880 119. Install cover
(14) and six bolts (13). The torque for bolts
(13) is 60 7 Nm (44 5 lb ft).
27
Illustration 62
g00660849

1. Position the torque converter upright.
2. Install gasket (10).
3. Install O-ring seals (11) and (12).

Illustration 63 g00660847 123. Use Tooling (B)
in order to install seal (9) into retainer (8).
Illustration 64 g00660846 124. Install retainer
(8) and eight bolts (7). The torque for bolts (7)
is 60 7 Nm (45 5 lb ft).
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Note It is necessary to install the torque
converter into the torque converter housing prior
to installation of the idler gear.

• Illustration 65 g00665414
• Install Tooling (A) to the torque converter
  housing.
• Attach a suitable lifting device and lifting
  chains to Tooling (A), as shown.
• Use the suitable lifting device in order to
  install the torque converter housing to the
  torque converter. The weight of the torque
  converter housing is 270 kg (600 lb).

Illustration 66
g00665412
128. Install eleven bolts (6) and the washers.
29
Illustration 67
g00665121

1. Install yoke (5).
2. Install O-ring seal (4).

Illustration 68 g00665406 131. Install bolt (2)
and retainer (3). The torque for bolt (2) is 240
25 Nm (175 20 lb ft).
Illustration 69
g00660841
132. Install speed sensor (1). End By
30

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.

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Shutdown SIS
Previous Screen
Product WHEEL LOADER Model 988K WHEEL LOADER
T8E Configuration 988K Wheel Loader T8E00001-UP
(MACHINE) POWERED BY C18 Engine Disassembly and
Assembly 836K Landfill Compactor, 834K Wheel
Dozer and 988K Wheel Loader Power Train Media
Number -KENR6490-06 Publication Date
-01/09/2015 Date Updated -05/12/2017
i05590451
Modulating Valve (Torque Converter Lockup Clutch)
- Remove and Install SMCS - 3139-010-VC Removal
Procedure Start By a. Connect the steering frame
lock. NOTICE Care must be taken to ensure that
fluids are contained during performance of
inspection, maintenance, testing, adjusting, and
repair of the product. Be prepared to collect the
fluid with suitable containers before opening any
compartment or disassembling any component
containing fluids. Refer to Special Publication,
NENG2500, "Dealer Service Tool Catalog" for tools
and supplies suitable to collect and contain
fluids on Cat products. Dispose of all fluids
according to local regulations and mandates.
Personal injury can result from hot oil spray.
33
Make sure all attachments have been lowered, oil
is cool and the pressure has been released from
the hydraulic system before removing any
components or lines. Be sure there is no pressure
in the tubing before it is disconnected from the
fitting. Do not allow hot oil or components to
contact skin.
Note The modulating valve for the torque
converter lockup clutch is mounted on the torque
converter below the steering pump.
Illustration 1 g03548757 1. Disconnect harness
assembly (2). Remove two bolts (3) and modulating
valve (1).
Illustration 2 g00681068 2. Remove seal (4) from
modulating valve (1).
34
Illustration 3
g01141308
3. Remove nut (5) and coil assembly (6).
Illustration 4
g01141309
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.
4. Remove cartridge assembly (7) from valve body
(8).
35
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