Locking Differential Adjustment 8.6, 9.5LD Inch Axle

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:

1. Install the new locking differential clutch disc thrust washer.



2. Install the locking differential side gear cam unit and clutch disc assembly.

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

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

Note: 

•	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.

•	Tighten the pinion shaft lock bolt finger tight.

4. Install the pinion shaft and the bolt.
5. Rotate the pinion gear closest to the lock bolt so that one of the teeth is pointing downward, square to the ring gear flange.
6. Install a brass drift between the locking differential side gear cam unit and the pinion shaft.
7. 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 base  (1) and the J 8001 indicator  (2) to the ring gear flange.

8.2.	Place the contact pad of the J 8001 indicator  (2) on one of the teeth of the pinion gear closest to the pinion shaft lock bolt and zero the gauge.

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

8.4.	Rotate the pinion gear back and forth.

Note:     •  If the backlash is greater than, install a thicker locking differential clutch disc thrust washer and recheck the backlash.    •  If the backlash is less than, install a thinner locking differential clutch disc thrust washer and recheck the backlash

8.5.	The backlash between the differential pinion gear and the locking differential side gear cam unit should be:

•	For the 8.6 inch axle, 0.254-0.406 mm (0.010-0.016 in).

•	For the 9.5 LD axle, 0.279-0.432 mm (0.011-0.017 in).

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

Washer Sizes

•	0.559 mm (0.022 in)

•	0.686 mm (0.027 in)

•	0.813 mm (0.032 in)

•	0.914 mm (0.036 in)

•	1.016 mm (0.040 in)

•	1.118 mm (0.044 in)

•	1.219 mm (0.048 in)

•	1.321 mm (0.052 in)

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 of the differential case.
3. Install the locking differential side gear and clutch disc assembly.
4. Align the openings of the differential pinion gears and the differential pinion gear thrust washers to the pinion shaft opening in the differential case.

Note: 

•	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

5. Install the differential pinion gears with the differential pinion thrust washers into the differential case.

Note: Tighten the pinion shaft lock bolt finger tight.

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



8. Install a brass drift between the locking differential side gear and the pinion shaft.
9. Press the brass drift in enough in order to compress the clutch discs.



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

10.1.

Install the J 7872 base  (1)and the J 8001 indicator  (2) to the ring gear flange.

10.2.

Place the contact pad of the J 8001 indicator  (2) on one of the teeth of the pinion gear closest to the pinion shaft lock bolt and zero the gauge.

10.3.

Pull the pinion gear firmly into the differential case seat.

10.4.

Rotate the pinion gear back and forth.

Note:     •  If the backlash is greater than, install a thicker locking differential clutch disc thrust washer and recheck the backlash.    •  If the backlash is less than, install a thinner locking differential clutch disc thrust washer and recheck the backlash

10.5.

The backlash between the differential pinion gear and the locking differential side gear cam unit should be:

•	For the 8.6 inch axle 0.076-0.229 mm (0.003-0.009 in).

•	For the 9.5 LD axle 0.051-0.203 mm (0.002-0.008 in).

Differential side gear shims are available in the following sizes:

Shim Sizes

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 of the differential case.
4. Install the locking differential side gear and clutch disc assembly into the right side of the differential case.

Note: Tighten the pinion shaft bolt finger tight.

5. Install the pinion shaft and the bolt.



6. Install a brass drift between the left locking differential side gear cam unit and the pinion shaft.
7. 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.
9. 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.

10. Using a 25.4-50.8 mm (1-2 in) telescoping gage, measure the distance between the side gear faces.
11. Measure the telescoping gage with a micrometer and record the measurement.

Note: If the measurement is equal to one of the thrust blocks sizes available, then select that thrust block.

12. Compare the measurement obtained in step 11 to the thrust block sizes available.

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

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)for the 8.6 inch axle or 40.488 mm (1.622 in) for the 9.5LD axle, 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)for the 8.6 inch axle or 41.120 mm (1.622 in) for the 9.5LD axle, 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 10.5 Inch Axle

Note: 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:

1. Install the locking differential clutch disc thrust washer.



2. Install the locking differential clutch disc set.



3. Install the differential side gear.




Note: 

•	The bolt must be long enough to hold the differential side gear in place and to allow the use of washers and nut.

•	The washers must be the proper size in order to fit over the differential side gear, but without causing interference with the with the differential pinion gear and differential spider assembly.

•	Tighten the nut and bolt just enough compress the clutch disc but will allow locking differential side gear to rotate.

4. Install the long bolt, washers and nut
5. Install the differential case half into a vise.
6. Clamp on the nut on the bottom of the differential case.




Note: Index the pinion gear so that one tooth is pointing downward, square to the case half face.

7. Install the differential pinion gears, thrust washers and the locking differential spider into the case half.



8. Install the J 7872 base and the J 8001 indicator on the differential case.

Note: Preload the dial of the J 8001 indicator approximately one turn clockwise.

9. Adjust the J 8001 indicator on the tooth that is square to the differential side gear and set the J 8001 indicator to zero

Note: In the following procedure, DO NOT unseat the locking differential spider. This will make the backlash reading inaccurate.

10. 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.

•	Record the measurement.

Note: Measure the differential pinion gear to locking differential side gear backlash on the remaining differential pinion gears following the previous steps.

11. 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).

Note: 

•	If the backlash is greater than, install a thicker differential side gear shim and recheck the backlash.

•	If the backlash is less than, use a thinner differential side gear shim and recheck the backlash.

12. Differential side gear shims are available in the following sizes:

Shim Sizes

1. Install the locking differential clutch disc thrust washer.



2. Install the locking differential cam unit.




Note: 

•	The bolt must be long enough to hold the differential side gear in place and to allow the use of washers and nut.

•	The washers must be the proper size in order to fit over the differential side gear, but without causing interference with the with the differential pinion gear and differential spider assembly.

•	Tighten the nut and bolt just enough compress the clutch disc but will allow locking differential side gear to rotate.

3. Install the long bolt, washers and nut
4. Install the differential case half into a vise.
5. Clamp on the nut on the bottom of the differential case.




Note: Index the pinion gear so that one tooth is pointing downward, square to the case half face.

6. Install the differential pinion gears, thrust washers and the locking differential spider into the case half.



7. Install the J 7872 base and the J 8001 indicator on the differential case.

Note: Preload the dial of the J 8001 indicator approximately one turn clockwise.

8. Adjust the J 8001 indicator on the tooth that is square to the differential side gear and set the J 8001 indicator to zero

Note: In the following procedure, DO NOT unseat the locking differential spider. This will make the backlash reading inaccurate.

9. 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.

•	Record the measurement.

Note: Measure the differential pinion gear to locking differential side gear backlash on the remaining differential pinion gears following the steps above.

10. 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).

Note: 

•	If the backlash is greater than, install a thicker differential side gear shim and recheck the backlash.

•	If the backlash is less than, use a thinner differential side gear shim and recheck the backlash.

11. Differential side gear shims are available in the following sizes:

Washer Sizes

•	0.559 mm (0.022 in)

•	0.686 mm (0.027 in)

•	0.813 mm (0.032 in)

•	0.914 mm (0.036 in)

•	1.016 mm (0.040 in)

•	1.067 mm (0.042 in)

•	1.118 mm (0.044 in)

•	1.219 mm (0.048 in)

•	1.321 mm (0.052 in)

Note: 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.



2. Install the clutch pack assembly.



3. Install the differential side gear.
4. Assemble a set of washers, a nut, and a bolt long enough in order to hold the side gear in place.



5. Install the bolt and washer assembly through the differential case half.
6. Install a second set of washers and the nut onto the bolt extending through the differential case half.
7. Install the differential case half into a vise.
8. Clamp on the nut on the bottom of the differential case.
9. Tighten the bolt until the clutch plates are compressed.




Note: To perform the following measurement procedure, 2 of the J 34673 Flat Gage Bar will be needed.

10. Install the J 34673 bar  (2) and the J 34672 micrometer  (1) onto the differential case as shown.
11. Install the J 34673  onto the face of the differential case, not the ridge of the differential case, or an inaccurate measurement will result.
12. Using the J 34672 micrometer and the J 34673 bar , measure and record the depth from the face of the to the face of the differential side gear.
13. Measure the thickness of the J 34673 bar subtract from the measurement obtained in step 10 and record the measurement. This measurement is equal to one-half of the thrust block thickness.
14. Remove the differential case half from the vise.



15. Install the locking differential clutch disc thrust washer.



16. Install the differential side gear cam unit.
17. Assemble a set of washers, a nut, and a bolt long enough in order to hold the side gear in place.




Note: 

•	The bolt must be long enough to hold the differential side gear in place and to allow the use of washers and nut.

•	The washers must be the proper size in order to fit over the differential side gear, but without causing interference with the with the differential pinion gear and differential spider assembly.

•	Tighten the nut and bolt just enough compress the clutch disc but will allow locking differential side gear to rotate.

18. Install the long bolt, washers and nut
19. Install the differential case half into a vise.
20. Clamp on the nut on the bottom of the differential case.



21. Install the J 34673 bar  (2) and the J 34672 micrometer  (1) onto the differential case.
22. Using the J 34673 bar and the J 34672 micrometer , measure and record the depth from the face of the to the face of the differential side gear.

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

23. Measure the thickness of the J 34673 bar subtract from the measurement obtained in step 23.
24. Add the measurements in step 12 and step 25 together. This is the thickness for the thrust block.

Note: 

•	If the measurement is equal to one of the thrust block sizes available, the select that thrust block.

•	If the measurement is less than one of the thrust block sizes available, then select the next smaller thrust block.

25. Compare the measurement obtain in step 25 to the thrust block sizes available.

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

26. If the measurement obtained in step 25 is less then 40.488 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.
27. If the measurement obtained in step 25 is greater then 41.120 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.
28. Recheck the left and/or right side gear backlash and adjust as necessary.
29. Recheck the thrust block clearance and adjust as necessary.