Locking Differential Adjustment 10.5 Inch Axles

Tools Required

Adjustment of the Differential

Important: If it is necessary to replace the right side cam gear and clutch disc assembly, the left hand side gear and clutch disc assembly, or the thrust block, the entire differential must be adjusted. The differential is adjusted using selective thickness thrust washers between the clutch pack assemblies and case and/or different selective thickness thrust blocks.

When adjusting the differential, note the following:

•	Build up the clutch disc packs properly.

Proper clearance between the parts is critical to the operation of the unit.

•	Adjust the backlash and thrust block clearance in the following order:

-	The left side gear backlash

-	The right side gear backlash

-	The thrust block clearance

Left Side Gear Backlash Adjustment

1. Install the original locking differential clutch disc thrust washer into the differential case half.



2. Install the differential side gear cam unit and clutch disc assembly into the differential case half.



3. Clamp the differential side gear cam unit and clutch disc assembly in place using a set of washers, a nut, and a bolt long enough to hold the side gear in place.
4. Install the differential case half into a vise.

Clamp on the nut on the bottom of the case.

5. Install the differential pinion gears, the differential pinion gear thrust washers and the locking differential spider into the case half.
6. Loosen the bolt in order to turn the differential side gear.
7. Index the pinion gear so that one tooth is pointing downward, perpendicular to the case half face.
8. Tighten the bolt until the clutch plates are compressed.



9. Install the J 7872 onto the differential case.
10. Loosely clamp the J 8001-3 onto the stem of the J 7872 .
11. Place the contact pad of the J 8001-3 on the tooth that is perpendicular to the differential side gear.
12. Preload the dial of the J 8001-3 approximately 1 turn clockwise.
13. Tighten the lock nut on the J 7872 finger tight.
14. Turn the dial of the J 8001-3 until the needle and the dial face indicate ZERO.
15. Measure the differential pinion gear to locking differential side gear backlash by performing the following steps:

15.1.

Pull the pinion gear firmly into the seat.

15.2.

Rotate the pinion gear back and forth while reading the dial indicator.

Do not unseat the locking differential spider. This will make the backlash reading inaccurate.

15.3.

Record the measurement.

16. Measure the differential pinion gear to locking differential side gear backlash on the other 2 pinion gears following the steps above.

Specification
The backlash between the differential pinon gear and locking differential side gear should be between 0.279-0.432 mm (0.011-0.017 in).

17. If the backlash is too large, install a thicker locking differential side gear thrust washer and check the backlash.
18. If the backlash is too small, use a thinner locking differential side gear thrust washer and check the backlash.

Locking differential clutch disc thrust washers are available in the following sizes:

Washer Sizes

Right Side Gear Backlash Adjustment

1. Install the original differential side gear shim into the differential case half.



2. Install the differential side gear clutch pack assembly into the differential case half.



3. Install the differential side gear into the differential case half.
4. Clamp the differential side gear and clutch pack assembly in place using a set of washers, a nut, and a bolt long enough to hold the side gear in place.
5. Install the differential case half into a vise.

Clamp on the nut on the bottom of the case.

6. Install the differential pinion gears, the differential pinion gear thrust washers and the locking differential spider into the case half.
7. Loosen the bolt in order to turn the differential side gear.
8. Index the pinion gear so that one tooth is pointing downward, perpendicular to the case half face.
9. Tighten the bolt until the clutch plates are compressed.



10. Install the J 7872 onto the differential case.
11. Loosely clamp the J 8001-3 onto the stem of the J 7872 .
12. Place the contact pad of the J 8001-3 on the tooth that is perpendicular to the differential side gear.
13. Preload the dial of the J 8001-3 approximately 1 turn clockwise.
14. Tighten the lock nut on the J 7872 finger tight.
15. Turn the dial of the J 8001-3 until the needle and the dial face indicate ZERO.
16. Measure the differential pinion gear to locking differential side gear backlash by performing the following steps:

•	Pull the pinion gear firmly into the seat.

•	Rotate the pinion gear back and forth while reading the dial indicator.

•	Do not unseat the locking differential spider. This will make the backlash reading inaccurate.

•	Record the measurement.

17. Measure the differential pinion gear to locking differential side gear backlash on the other 2 pinion gears following the steps above.

Specification
The backlash between the differential pinon gear and locking differential side gear should be between 0.051-0.203 mm (0.002-0.008 in).

18. If the backlash is too large, install a thicker differential side gear shim and check the backlash.
19. If the backlash is too small, use a thinner differential side gear shim and check the backlash.

Differential side gear shims are available in the following sizes:

Shim Sizes

Thrust Block Clearance Adjustment

Important: The left and right side gear backlash measurements must be done before the thrust block measurement can be completed.

1. Install the differential side gear shim into the differential case half.



2. Install the differential side gear clutch disc assembly into the differential case half.



3. Install the differential side gear into the differential case half.
4. Clamp the differential side gear and clutch disc assembly in place using a set of washers, a nut, and a bolt long enough to hold the side gear in place.
5. Install the differential case half into a vise.

Clamp on the nut on the bottom of the case.

6. Tighten the bolt until the clutch plates are compressed.



7. Install the J 34673  (2) and the J 34672  (1) onto the differential case as shown.
8. Measure the depth from the face of the J 34673 to the face of the differential side gear using the J 34672 .

Record the measurement.

9. Measure the thickness of the J 34673 .
10. Subtract the thickness of the J 34673 from the measurement obtained in step 8.

Record the measurement. This measurement is equal to one-half of the thrust block thickness.

11. Remove the J 34673 and the J 34673 from the differential case.
12. Remove the differential case half from the vise.



13. Install the locking differential clutch disc thrust washer into the differential case half.



14. Install the differential side gear cam unit and clutch disc assembly into the differential case half.



15. Clamp the differential side gear cam unit and clutch disc assembly in place using a set of washers, a nut, and a bolt long enough to hold the side gear in place.
16. Install the differential case half into a vise.

Clamp on the nut on the bottom of the case.

17. Tighten the bolt until the clutch plates are compressed.



18. Install the J 34673  (2) and the J 34672  (1) onto the differential case as shown.
19. Measure the depth from the face of the J 34673 to the face of the differential side gear using the J 34672 .

Record the measurement.




20. Measure the depth from the face of the J 34673 to the face of the differential case.
21. Subtract the measurement obtained in step 20 from the measurement obtained in step 19.

Record the measurement. This measurement is equal to one-half of the thrust block thickness.

22. Add the measurements in Step 10 and Step 21 together. This is the thickness for the thrust block.
23. Compare the measurement obtain in Step 22 to the thrust block sizes available. If the measurement is equal to one of the thrust block sizes available, the select that thrust block.
24. If the measurement obtained in Step 22 is not equal to one of the thrust block sizes available, then select the thrust block that is smaller the measurement.

For example, if the measurement is 40.92 mm (1.611 in), select the 40.89 mm (1.610 in) thrust block.

Important: The backlash must be checked and adjusted to specification anytime the left and/or the right thrust washers are replaced.

25. If the measurement obtained in Step 22 is less then 40.49 mm (1.594 in), then reduce the left differential side gear shim or the right locking differential clutch disc thrust washer thickness in order to increase the thrust block opening.
26. If the measurement obtained in Step 22 is greater then 41.20 mm (1.622 in), then increase the left differential side gear shim or the right locking differential clutch disc thrust washer thickness in order to decrease the thrust block opening.
27. Check the left and/or right side gear backlash and adjust as necessary.
28. Check the thrust block clearance and adjust as necessary.
29. Assemble the differential. Refer to Locking Differential Assemble .

Locking Differential Adjustment 8.6 Inch Axles

Special Tools

Adjustment of the Differential

Note: If it is necessary to replace the left side locking differential side gear cam unit and clutch disc assembly, the right side locking differential side gear and clutch disc assembly, or the thrust block, the entire differential must be adjusted. The differential is adjusted using selective thickness thrust washers between the clutch disc assemblies and the case and/or different selective thickness thrust blocks.

When adjusting the differential, note the following:

Left Side Gear Backlash Adjustment

1. Install the new locking differential clutch disc thrust washer into the left side or flange-end of the differential case.



2. Install the locking differential side gear cam unit and clutch disc assembly into the left side or flange-end of the differential case.
3. Install the differential pinion gears with the differential pinion gear thrust washers into the differential case.

Align the openings of the differential pinion gears and the differential pinion gear thrust washer to the pinion shaft opening in the differential case.

4. Install the pinion shaft. It may be necessary to press down on the locking differential side gear cam unit in order to align the pinion gear shaft opening with the pinion shaft opening in the differential case.

If the pinion shaft cannot be installed after pressing on the locking differential side gear cam unit, replace the locking differential clutch disc gear thrust washer with a thinner washer.

Caution: Refer to Fastener Caution in the Preface section.

5. Install the pinion shaft lock bolt. Tighten the pinion shaft lock bolt finger tight.
6. Rotate the pinion gear closest to the lock bolt so that one of the teeth is pointing downward, perpendicular to the ring gear flange.
7. Install a brass drift between the locking differential side gear cam unit and the pinion shaft.

Press the brass drift in far enough in order to compress the clutch discs.




8. Measure the backlash of the differential pinion gear and the locking differential side gear cam unit by doing the following:

8.1.	Install the J 7872  (1) to the ring gear flange.

8.2.	Loosely clamp the J 8001-3  (2) onto the stem on the J 7872  (1).

8.3.	Place the contact pad of the J 8001-3 on one of the teeth of the pinion gear closest to the pinion shaft lock bolt.

Turn the dial of the J 8001-3 until the needle and the dial face indicate ZERO.

8.4.	Tighten the lock nut of the J 8001-3 finger tight.

8.5.	Pull the pinion gear firmly into the differential case seat.

8.6.	Rotate the pinion gear back and forth.

8.7.	Measure the backlash.

Specification
The backlash between the differential pinion gear and the locking differential side gear cam unit should be 0.254-0.406 mm (0.010-0.016 in).

9. If the backlash is too large, install a thicker locking differential clutch disc thrust washer and recheck the backlash.
10. If the backlash is too small, install a thinner locking differential clutch disc thrust washer and recheck the backlash.

Locking differential clutch disc thrust washers are available in the following sizes:

Washer Sizes

Right Side Gear Backlash Adjustment

1. If necessary, remove the following from the differential case:

1.1.	The pinion lock shaft bolt

1.2.	The pinion shaft

1.3.	The differential pinion gears

1.4.	The differential pinion gear thrust washers

1.5.	The left side locking differential side gear cam unit and clutch disc assembly

2. Install the differential side gear shim into the right side or bell-end of the differential case.
3. Install the locking differential side gear and clutch disc assembly into the right side or bell-end of the differential case.
4. Install the differential pinion gears with the differential pinion thrust washers into the differential case.

Align the openings of the differential pinion gears and the differential pinion gear thrust washers to the pinion shaft opening in the differential case.

5. Press down on the locking differential side gear and install the pinion shaft.

If the side gear cannot be pressed down far enough to install the pinion shaft, replace the side gear shim with a thinner shim.

6. Install the pinion shaft lock bolt. Tighten the pinion shaft lock bolt finger tight.
7. Rotate the differential pinion gear so that one of the teeth is pointing downward, perpendicular to the ring gear flange.



8. Install a brass drift between the locking differential side gear and the pinion shaft.

Press the brass drift in enough in order to compress the clutch discs.




9. Measure the backlash of the pinion gear and the right side gear by doing the following:

9.1.	Install the J 7872  (1) to the ring gear flange.

9.2.	Loosely clamp the J 8001-3  (2) onto the stem on the J 7872  (1).

9.3.	Place the contact pad of the J 8001-3 on one of the teeth of the pinion gear closest to the pinion shaft lock bolt.

Turn the dial of the J 8001-3 until the needle and the dial face indicate ZERO.

9.4.	Tighten the lock nut of the J 8001-3 finger tight.

9.5.	Pull the pinion gear firmly into the differential case seat.

9.6.	Rotate the pinion gear back and forth.

9.7.	Measure the backlash.

Specification
The backlash for the pinion gears should be 0.076-0.229 mm (0.003-0.009 in).

10. If the backlash is too large, install a thicker differential side gear shim and check the backlash.
11. If the backlash is too small, install a thinner differential side gear shim and check the backlash again.

Differential side gear shims are available in the following sizes:

Shim Sizes

Thrust Block Clearance Adjustment

Note: The left and right side gear backlash measurements must be done before the thrust block measurement can be completed.

1. Install the locking differential clutch disc thrust washer into the left side or flange-end of the differential case.



2. Install the locking differential side gear cam unit and clutch disc assembly into the left side or flange-end of the differential case.
3. Install the differential side gear shim into the right side or bell-end of the differential case.
4. Install the locking differential side gear and clutch disc assembly into the right side or bell-end of the differential case.
5. Install the pinion shaft.
6. Install the pinion shaft bolt. Tighten the pinion shaft bolt finger tight.



7. Install a brass drift between the left locking differential side gear cam unit and the pinion shaft.

Press the brass drift in far enough in order to compress the clutch disc assembly and hold the left side gear assembly in place.

8. Install a brass drift between the right side locking differential side gear and the pinion shaft.

Press the brass drift in far enough in order to hold the right side gear assembly in place.





Note: Do not measure the distance between the side gear teeth.

9. Measure the distance between the side gear faces using a 25.4-50.8 mm (1-2 in) telescoping gage.
10. Remove the telescoping gage.
11. Measure the telescoping gage with a micrometer.

Record the measurement.

12. Compare the measurement obtained in step 11 to the thrust block sizes available. If the measurement is equal to one of the thrust blocks sizes available, then select that thrust block.
13. If the measurement obtained in step 11 is not equal to one of the thrust blocks sizes available, then select the thrust block that is smaller than the measurement.

For example, if the measurement is 33.833 mm (1.332 in), select the 33.782 mm (1.330 in) thrust block.

Note: The backlash must be rechecked and adjusted to specification anytime the left and/or the right thrust washers are replaced.

14. If the measurement obtained in step 11 is less than 33.578 mm (1.322 in), then reduce the left side gear thrust washer or the right side gear shim thickness in order to increase the thrust block opening.
15. If the measurement obtained in step 11 is greater than 34.290 mm (1.350 in), then increase the left side gear thrust washer or the right side gear shim thickness in order to decrease the thrust block opening.
16. Recheck the left and/or right side gear backlash and adjust as necessary.
17. Recheck the thrust block clearance and adjust as necessary.
18. Assemble the differential. Refer to Locking Differential Assemble.

Locking Differential Adjustment 9.75 Inch Axles

Special Tools

J 7872 Magnetic Base Dial Indicator

Adjustment of the Differential

Note: If it is necessary to replace the left side gear cam unit and disc assembly, the right side gear and disc assembly, or the thrust block, the entire differential must be adjusted. The differential is adjusted using selective thickness thrust washers between the clutch disc assemblies and the case and/or different selective thickness thrust blocks.

When adjusting the differential, note the following:

Left Side Gear Backlash Adjustment

1. Install the original left side thrust washer into the left side or flange-end of the differential case.



2. Install the left side locking differential side gear cam unit and clutch disc assembly into the left side or flange-end of the differential case.



3. Install the differential pinion gears with the differential pinion gear thrust washers into the differential case.

Align the openings of the differential pinion gears and the differential pinion gear thrust washers to the pinion shaft opening in the differential case.

4. Install the pinion shaft. It may be necessary to press down on the side gear in order to align the pinion gear shaft opening with the pinion shaft opening in the differential case.

If the pinion shaft cannot be installed after pressing on the side gear, replace the locking differential clutch disc thrust washer with a thinner washer.

Caution: Refer to Fastener Caution in the Preface section.




5. Install the pinion shaft lock bolt. Tighten the pinion shaft lock bolt finger tight.
6. Rotate the pinion gear closest to the lock bolt so that one of the teeth is pointing downward, perpendicular to the ring gear flange.
7. Install a brass drift between the side gear and the pinion shaft.

Press the brass drift in far enough in order to compress the clutch discs.




8. Measure the backlash of the pinion gear and the side gear by doing the following:

8.1.	Install the J 7872  (1) to the ring gear flange.

8.2.	Loosely clamp the J 8001-3  (2) onto the stem on the J 7872  (1).

8.3.	Place the contact pad of the J 8001-3 on one of the teeth of the pinion gear closest to the pinion shaft lock bolt.

Turn the dial of the J 8001-3 until the needle and the dial face indicate ZERO.

8.4.	Tighten the lock nut of the J 8001-3 finger tight.

8.5.	Pull the pinion gear firmly into the differential case seat.

8.6.	Rotate the pinion gear back and forth.

8.7.	Measure the backlash.

Specification
The backlash between the differential pinon gear and locking differential side gear should be between 0.279-0.432 mm (0.011-0.017 in).

9. If the backlash is too large, install a thicker locking differential clutch disc thrust washer and recheck the backlash.
10. If the backlash is too small, install a thinner locking deferential clutch disc thrust washer and recheck the backlash.

Locking differential clutch disc thrust washers are available in the following sizes:

Washer Sizes

Right Side Gear Backlash Adjustment

1. If necessary, remove the following from the differential case:

1.1.	The pinion lock shaft bolt

1.2.	The pinion shaft

1.3.	The differential pinion gears

1.4.	The differential pinion gear thrust washers

1.5.	The locking differential side gear cam unit and clutch disc assembly

2. Install the right side differential side gear shim into the right side or bell-end of the differential case.
3. Install the clutch disc assembly into the right side or bell-end of the differential case.
4. Install the locking differential side gear.
5. Install the differential pinion gears with the differential pinion thrust washers into the differential case.

Align the openings of the differential pinion gears and the differential pinion thrust washer to the pinion shaft opening in the differential case.

6. Press down on the locking differential side gear and install the pinion shaft.

If the side gear cannot be pressed down far enough to install the pinion shaft, replace the differential side gear shim with a thinner shim.

Caution: Refer to Fastener Caution in the Preface section.

7. Install the pinion shaft lock bolt. Tighten the pinion shaft lock bolt finger tight.
8. Rotate the differential pinion gear so that one of the teeth is pointing downward, perpendicular to the ring gear flange.
9. Install a brass drift between the differential side gear and the pinion shaft.

Press the brass drift in enough in order to compress the clutch discs.




10. Measure the backlash of the differential pinion gear and the locking differential side gear by doing the following:

10.1.

Install the J 7872  (1) to the ring gear flange.

10.2.

Loosely clamp the J 8001-3  (2) onto the stem on the J 7872  (1).

10.3.

Place the contact pad of the J 8001-3 on one of the teeth of the pinion gear closest to the pinion shaft lock bolt.

Turn the dial of the J 8001-3 until the needle and the dial face indicate ZERO.

10.4.

Tighten the lock nut of the J 8001-3 finger tight.

10.5.

Pull the pinion gear firmly into the differential case seat.

10.6.

Rotate the pinion gear back and forth.

10.7.

Measure the backlash.

Specification
The backlash between the differential pinion gear and the locking differential side gear should be 0.051-0.203 mm (0.002-0.008 in).

11. If the backlash is too large, install a thicker locking differential side gear shim and check the backlash.
12. If the backlash is too small, install a thinner locking differential side gear shim and check the backlash.

Differential side gear shims are available in the following sizes:

Shim Sizes

Thrust Block Clearance Adjustment

Note: The left and right side gear backlash measurements must be done before the thrust block measurement can be completed.

1. Install the locking differential clutch disc thrust washer into the left side or flange-end of the differential case.



2. Install the locking differential side gear cam unit and clutch disc assembly into the left side or flange-end of the differential case.
3. Install the right side differential side gear shim into the right side or bell-end of the differential case.



4. Install the right side locking differential side gear and clutch disc assembly into the right side or bell-end of the differential case.
5. Install the pinion shaft.
6. Install the pinion shaft bolt. Tighten the pinion shaft bolt finger tight.



7. Install a brass drift between the left side gear and the pinion shaft.

Press the brass drift in far enough in order to compress the clutch disc assembly and hold the left side gear assembly in place.

8. Install a brass drift between the right side gear and the pinion shaft.

Press the brass drift in far enough in order to hold the right side gear assembly in place.





Note: Do not measure the distance between the side gear teeth.

9. Measure the distance between the side gear faces using a 25.4-50.8 mm (1-2 in) telescoping gage.
10. Remove the telescoping gage.
11. Measure the telescoping gage with a micrometer.

Record the measurement.

12. Compare the measurement obtained in Step 11 to the thrust block sizes available. If the measurement is equal to one of the thrust blocks sizes available, then select that thrust block.
13. If the measurement obtained in Step 11 is not equal to one of the thrust blocks sizes available, then select the thrust block that is smaller than the measurement.

For example, if the measurement is 40.87 mm (1.609 in), select the 40.79 mm (1.606 in) thrust block.

Note: The backlash must be checked and adjusted to specification anytime the left and/or the right thrust washers are replaced.

14. If the measurement obtained in Step 11 is less than 40.49 mm (1.594 in), then reduce the left side gear thrust washer or the right side gear shim thickness in order to increase the thrust block opening.
15. If the measurement obtained in Step 11 is greater than 41.20 mm (1.622 in), then increase the left side gear thrust washer or the right side gear shim thickness in order to decrease the thrust block opening.
16. Check the left and/or right side gear backlash and adjust as necessary.
17. Check the thrust block clearance and adjust as necessary.
18. Assemble the differential. Refer to Locking Differential Assemble.