Differential Carrier Bearing Preload Adjustment (G86)

Special Tools DT-22779 Side Bearing Backlash Gauge DT-52901 Main Bearing Cap Bridge Assembly Equivalent regional tools: Special Tools Wedge Method

Note

The differential side bearing preload adjustment must be completed before the backlash adjustment can be started. In order to maintain the original backlash, adjust the differential case side bearing preload by changing the thickness of the left and the right side shim packs equally. Measure the service shims and the spacers one at a time. Add the measurements together in order to obtain the total thickness of the left or the right side shim pack. Do not use or reuse the original cast iron production shims. Use service shims and spacers instead.

Note

Record the measurement for re-assembly.

1. Using an inch pound torque wrench, measure the rotating torque of the drive pinion. The rotating torque should match the specifications, refer to Axle Preload and Backlash Specifications.

Note

Before installation of the differential assembly, ensure that the differential side bearing surfaces in the axle housing are clean and free of burrs. If the original differential side bearings are to be reused, the original differential side bearing cups must also be used.

2. Install the differential assembly with the differential side bearings and differential side bearing cups into the axle housing.
3. Insert one 4.55 mm (0.179 in) thick service spacer into the left side of the axle housing.
4. Slide the differential assembly towards the service spacer in order to hold the spacer in place.
5. Install the DT-22779 Side Bearing Backlash Gauge between the right side differential side bearing cup and the axle housing.

Note

Over-tightening of the DT-22779 Side Bearing Backlash Gauge may spread the housing and result in incorrect shim selection.

6. Tighten the knob on the DT-22779 Side Bearing Backlash Gauge until there is moderate drag when the J-22779 Side Bearing Backlash Gauge is moved.
7. Remove the DT-22779 Side Bearing Backlash Gauge.
8. Remove the service spacer.

Note

Record the measurement.

9. Using a micrometer, measure the thickness of the service spacer.

Note

Record the measurement.

10. Using a micrometer, measure the thickness of the DT-22779 Side Bearing Backlash Gauge in 3 locations. Calculate the average of the 3 measurements.
11. Add the thickness of the service spacer, measured in step 9 to the average thickness of the DT-22779 Side Bearing Backlash Gauge, measured in step 10. The resulting value is the total service shim thickness without preload for the axle.
12. Insert one BENT 1.016 mm (0.040 in) service shim between the right side differential side bearing cup and the axle housing. The service shim must be installed between the service spacer and the differential side bearing cup.
13. Install the DT-22779 Side Bearing Backlash Gauge into the left side of the axle housing. The DT-22779 Side Bearing Backlash Gauge must be installed between the service spacer and the differential side bearing cup.
14. While rotating the ring gear back and forth, tighten the knob on the DT-22779 Side Bearing Backlash Gauge until there is approximately 0.025–0.051 mm (0.001–0.002 in) of backlash between the ring gear and the drive pinion.
15. Once the correct amount of backlash is obtained, remove the DT-22779 Side Bearing Backlash Gauge.
16. Remove the differential assembly with the differential side bearings and the differential side bearing cups.
17. Remove the BENT service shim.
18. Using a micrometer, measure the thickness of the DT-22779 Side Bearing Backlash Gauge in 3 locations. Calculate the average of the 3 measurements. This value is the left side service shim thickness without preload.
19. In order to determine the right side service shim thickness, subtract the service shim thickness for the left side of the axle, calculated in step 18, from the total service shim thickness, calculated in step 11. This value is the service shim thickness for the right side of the axle without preload.
20. In order to preload of the differential side bearings and set the backlash to approximately 0.127–0.223 mm (0.005–0.009 in), take the value determined in step 19 and add 0.203  mm (0.008 in) service shim thickness to this amount.
21. Assemble the left side shim pack using one 4.55 mm (0.179 in) service spacer and the appropriate amount of service shims equaling the thickness determined in step 18. Measure the service spacer and the service shims separately. Add the measurements together in order to determine the total shim pack thickness.
22. Assemble the right side shim pack using one 4.55 mm (0.179 in) service spacer and the appropriate amount of service shims equaling the thickness determined in step 20. Measure the service spacer and the service shims separately. Add the measurements together in order to determine the total shim pack thickness.
23. Install the differential assembly with the differential side bearings and the differential side bearing cups.
24. Install the left side service spacer and service shim into the axle housing. The service shim must be installed between the service spacer and the differential side bearing cup.
25. Install the right side service spacer between the axle housing and the differential side bearing cup.

Note

A dead blow hammer can be used to help seat the differential and shim.

26. Using a standard 14 inch c-clamp to squeeze the top and bottom of the differential housing, install the right side service shim. The service shim must be installed between the service spacer and the differential side bearing cup.
27. Install the DT-52901 Main Bearing Cap Bridge Assembly.

Caution

Refer to Fastener Caution.

28. Install and tighten the 4 rear axle housing cover bolts to hold DT-52901 Main Bearing Cap Bridge Assembly. Fastener Specifications
29. Rotate the pinion several times to ensure the drive pinion and differential side bearings have seated.

Note

Record the measurement.

30. Using an inch pound torque wrench, measure the rotating torque of the pinion and differential case bearing preload. The rotating torque should match the specifications, refer to Axle Preload and Backlash Specifications.
31. If the pinion and differential case bearing preload is not within specifications, add or subtract shim thickness equally from each shim pack as necessary in order to increase/decrease the side bearing preload.
32. Return to the previous procedure and continue from appropriate step which linked to this procedure. Shim Method

Note

The differential side bearing preload adjustment must be completed before the backlash adjustment can be started. In order to maintain the original backlash, adjust the differential case side bearing preload by changing the thickness of the left and the right side shim packs equally. Measure the service shims and the spacers one at a time. Add the measurements together in order to obtain the total thickness of the left or the right side shim pack. Do not use or reuse the original cast iron production shims. Use service shims and spacers instead.

Note

Record the measurement.

1. Using an inch pound torque wrench, measure the rotating torque of the drive pinion. The rotating torque should match the specifications, refer to Axle Preload and Backlash Specifications.

Note

Before installation of the case assembly, ensure that the side bearing surfaces in the axle housing are clean and free of burrs. If the original bearings are to be reused, the original bearing cups must also be used.

2. Install the differential assembly with the differential side bearings and bearing cups into the axle housing.
3. Insert one BENT 1.016 mm (0.040 in) thick service shim into the right side axle housing. Side the differential assembly towards the bent service shim in order to hold the shim in place.
4. While holding the differential assembly against the bent service shim, install one 4.55 mm (0.179 in) thick service spacer into the left side axle housing.
5. Move the differential assembly to the right until the ring gear contacts the drive pinion. Once the ring gear contacts the drive pinion, continue to move the ring gear towards the drive pinion to until all backlash is removed.
6. While holding the ring gear against the drive pinion, insert progressively larger service shims between the service spacer and the differential side bearing cup until a moderate resistance can be felt.
7. Once the largest service shim has been determined, measure the thickness of the shim using a micrometer. Measure the service shim in 3 locations. Calculate the average of the 3  measurements. Use the average as the thickness for the shim. Record the measurement.
8. Install the service shim that was just measured back into the left side of the axle housing. The service shim must be installed between the service spacer and the differential side bearing cup.
9. Remove the BENT shim from the right side of the axle housing.
10. Insert one 4.55 mm (0.179 in) thick service spacer into the right side axle housing.
11. Move the differential assembly towards the left side of the axle housing. While holding the differential assembly against the left side shim pack, insert progressively larger service shims between the service spacer and the differential side bearing cup until a moderate resistance can be felt.
12. Once the largest service shim has been determined, measure the thickness of the shim using a micrometer. Verify the thickness of the service shim. Measure the service shim in 3 locations. Calculate the average of the 3 measurements. Use the average as the thickness for the shim. Record the measurement.
13. In order to preload the differential side bearing and set the initial backlash to approximately 0.127 mm (0.005 in), adjust the thickness of left and right side shims by doing the following: 13.1. Subtract 0.152 mm (0.006 in) from the measurement recorded for the left side shim in step 7. Record the measurement. 13.2. Add 0.356 mm (0.014 in) to the measurement recorded for the right side shim in step 

Note

Using a micrometer, verify the thickness of the service shim. Measure the service shim in 3 locations.

14. Select the correct service shim thickness for each side corresponding to the measurements determined above. Calculate the average of the 3 measurements. Use the average as the thickness for the shim.
15. Install the left side service spacer and service shim into the axle housing. The service shim must be installed between the service spacer and the differential side bearing cup.
16. Move the differential assembly towards the left side of the axle housing.

Note

A dead blow hammer can be used to help seat the differential and shim.

17. Using a standard 14 inch c-clamp to squeeze the top and bottom of the differential housing, install the right side service shim. The service shim must be installed between the service spacer and the differential side bearing cup.
18. Install the DT-52901 Main Bearing Cap Bridge Assembly.

Caution

Refer to Fastener Caution.

19. Install and tighten the 4 rear axle housing cover bolts to hold DT-52901 Main Bearing Cap Bridge Assembly. Fastener Specifications
20. Rotate the pinion several times to ensure the bearings have seated.

Note

Record the measurement.

21. Using an inch pound torque wrench, measure the rotating torque of the pinion and differential case bearing preload. The rotating torque should match the specifications, refer to Axle Preload and Backlash Specifications.
22. If the pinion and differential case bearing preload is not within specifications, add or subtract shim thickness equally from each shim pack as necessary in order to increase/decrease the side bearing preload.
23. Return to the previous procedure and continue from appropriate step which linked to this procedure.