994 Wheel Loader Power Train Caterpillar

Illustration 1	g00288791

(15) Torque for bolt ... 570 ± 80 N·m (420 ± 60 lb ft)

(17) Torque for bolt ... 570 ± 80 N·m (420 ± 60 lb ft)

(23) Torque for 10 bolts ... 55 ± 10 N·m (41 ± 7 lb ft)

Note: Apply 7M-7260 Liquid Gasket on the seal bore surface in the case. Allow the gasket material to dry before installing the seal. Make sure that the gasket material is not applied to the lip seal. Lubricate the lip seal with a minimal amount of the lubricant which is being sealed.

Adjustment Procedure for the Bearing End Play

Note: Before assembly of the components, make sure that the bearing cups are seated in the housing and the bearing cage, and that the bearing cones are seated against the shoulders on the gear. Use a 0.038 mm (.0015 inch) thickness feeler gauge.

Adjustment for the Input Gear

Desired end play ... .050 ± .025 mm (.0020 ± .0010 inch)

1. Horizontally position housing (8) with the opening for bearing cage (4) on the top. Place gear (3) in the housing. Place bearing cage (4) without the shims on housing (8) .

2. Install two bolts (2) which are 180 degrees away from each other in bearing cage (4). Tighten bolts (2) finger tight. Alternately tighten each bolt to a torque of 40 N·m (30 lb ft).

3. Rotate gear (3) at least three revolutions or rotate the gear until the gear turns freely.

4. Tighten the bolts to a torque of 40 N·m (30 lb ft) for a second time.

5. Repeat Step 3 and Step 4 until the bolts do not move at a torque of 40 N·m (30 lb ft), and the bearings are binding. The bearings are binding if the gear does not turn freely after three revolutions.

6. Loosen the bolts evenly. Tighten the bolts finger tight. Do not move any other part.

7. With a tapered feeler gauge, measure gap (1) between housing (8) and bearing cage (4) in two places. Measure the gaps at 180 degree intervals.

8. To find the total thickness of the shims that are required, add 0.05 mm (.0020 inch) to the average of the two measurements in Step 7.

9. Remove bearing cage (4) .

10. Install the shims and the bearing cage.

11. To make sure that the gear turns freely, rotate gear (3) .

Adjustment for the Upper Idler Gear

Desired end play ... 0.000 to 0.050 mm (.0000 to .0020 inch)

1. Horizontally position housing (8) with the opening for bearing cage (7) on the top. Place gear (5) in the housing. Place bearing cage (7) without the shims or the seals on housing (8) .

2. Install two bolts (9) which are 180 degrees away from each other in bearing cage (7). Tighten bolts (9) finger tight. Alternately tighten each bolt to a torque of 40 N·m (30 lb ft).

3. Rotate gear (5) at least three revolutions or rotate the gear until the gear turns freely.

4. Tighten the bolts to a torque of 40 N·m (30 lb ft) for a second time.

5. Repeat Step 3 and Step 4 until the bolts do not move at a torque of 40 N·m (30 lb ft), and the bearings are binding. The bearings are binding if the gear does not turn freely after three revolutions.

6. Loosen the bolts evenly. Tighten the bolts finger tight. Do not move any other part.

7. With a tapered feeler gauge, measure gap (6) between housing (8) and bearing cage (7) in two places. Measure the gaps at 180 degree intervals.

8. To find the total thickness of the shims that are required, add 0.025 mm (.0010 inch) to the average of the two measurements in Step 7.

9. Remove bearing cage (7) .

10. Install the shims and the O-ring. Install the bearing cage.

11. To make sure that the gear turns freely, rotate gear (5) .

Adjustment for the Lower Idler Gear

Desired end play ... 0.025 to 0.075 mm (.0010 to .0030 inch)

1. Horizontally position housing (8) with the opening for bearing cage (14) on the top. Place gear (11) in the housing. Place bearing cage (14) without the shims or the seals on housing (8) .

2. Install two bolts (13) which are 180 degrees away from each other in bearing cage (14). Tighten bolts (13) finger tight. Alternately tighten each bolt to a torque of 40 N·m (30 lb ft).

3. Rotate gears (11) and (12) at least three revolutions or rotate the gears until the gears turn freely.

4. Tighten the bolts to a torque of 40 N·m (30 lb ft) for a second time.

5. Repeat Step 3 and Step 4 until the bolts do not move at a torque of 40 N·m (30 lb ft), and the bearings are binding. The bearings are binding if the gear does not turn freely after three revolutions.

6. Loosen the bolts evenly. Tighten the bolts finger tight. Do not move any other part.

7. With a tapered feeler gauge, measure gap (10) between housing (8) and bearing cage (14) in two places. Measure the gaps at 180 degree intervals.

8. To find the total thickness of the shims that are required, add 0.05 mm (.002 inch) to the average of the two measurements in Step 7.

9. Remove bearing cage (14) .

10. Install the shims and the O-ring. Install the bearing cage.

11. To make sure that the gears turn freely, rotate gears (11) and (12) .

Adjustment for the Output Shaft

Desired end play ... 0.075 to 0.150 mm (.0030 to .0059 inch)

Note: This procedure is done with bearing cage (18) off the housing.

Note: A tool is needed in order to align the two cones of the bearing. The tool consists of the following parts:

• (19) Sleeve. The length of the sleeve is 130.17 mm (5.125 inch). The diameter of the sleeve is 114.25 mm (4.50 inch).

• (20) 6Y-6681 Plates

• (21) 1D-4620 Bolt

Illustration 2	g00288792

1. Install the bearing cup in bearing cage (18). Before proceeding, make sure that the bearing cup is seated. Use a 0.038 mm (.0015 inch) thickness feeler gauge.

2. Install the bearing cones and install the remaining bearing cup into bearing cage (18) .

3. Install the tooling. Tighten the bolt and the nut.

4. Install retainer plate (22) with two bolts (23) which are 180 degrees away from each other in bearing cage (18). Tighten bolts (23) finger tight. Alternately tighten each bolt to a torque of 15 N·m (11 lb ft).

5. Rotate the bearings at least three revolutions or rotate the bearings until the bearings turn freely.

6. Tighten the bolts to a torque of 15 N·m (11 lb ft) for a second time.

7. Repeat Step 5 and Step 6 until the bolts do not move at a torque of 15 N·m (11 lb ft), and the bearings are binding. The bearings are binding if the gear does not turn freely after three revolutions.

8. Loosen the bolts evenly. Tighten the bolts finger tight. Do not move any other part.

9. With a tapered feeler gauge, measure gap (24) between retainer plate (22) and bearing cage (18) in two places. Measure the gaps at 180 degree intervals.

10. To find the total thickness of the shims that are required, add 0.35 mm (.014 inch) to the average of the two measurements in Step 9.

11. Remove retainer plate (22) .

12. Install the shims and install the retainer plate.

13. Remove the tooling which was installed in Step 4.

14. Install the gear and the spacer on the output shaft.

15. Install the output shaft in bearing cage (18) .

16. Install the yoke and the plate. Tighten bolt (15) .

17. To make sure that the output shaft turns freely, rotate the output shaft.

18. Remove the yoke if the output shaft turns freely. Install the lip seal. Install the yoke.

19. Install the output shaft and the bearing cage on housing (8) .

Checking Procedure for the End Play Adjustment

1. Loosen all the bearing cage bolts.

2. Turn the gears by using the bolt on the end of the output shaft.

3. Use a torque wrench to measure the torque that is necessary to rotate the output shaft and gears: (3), (5), (11) and (12). Record the torque value for reference.

4. Remove 0.10 mm (.004 inch) of the shims from the cage of the bearing.

5. Install the bearing cage with four equally spaced bolts. Tighten the bolts to a torque of 40 N·m (30 lb ft).

6. Measure the rolling torque again and record the value.

7. If the rolling torque in Step 6 is larger than the rolling torque in Step 3, the shaft end play is correct. Remove the bearing cage and add the shim that was removed in Step 4. Install the bearing cage.

8. If the rolling torque in Step 6 is identical to the rolling torque in Step 3, there is free play in the gear. An error has been made in measuring.

9. Repeat Step 4 through Step 6 until there is an increase in the rolling torque.

10. Add 0.05 mm (.002 inch) shims until the rolling torque is identical to the rolling torque in Step 3.

11. The end play is 0.00 to 0.05 mm (.000 to .002 inch) when the addition of one 0.05 mm (.002 inch) shim causes the rolling torque to be equal to the value in Step 3.

12. Add shims for correct end play. Install the bearing cage.