Differential Overhaul 8.6, 9.5 Inch Axles

1. Remove the differential side bearings. Refer to Differential Side Bearings Replacement .




Important: The ring gear bolts have left-hand threads.

2. Remove the ring gear bolts. Discard the bolts.

Notice: Refer to Ring Gear Removal Notice in the Preface section.




3. Remove the ring gear from the differential. Drive the gear off with a brass drift if necessary.



4. Remove the differential pinion gears and the differential side gears by doing the following:

4.1.	Remove the pinion shaft lock bolt

4.2.	Remove the pinion shaft.

4.3.	Roll the differential pinion gear out of the case with the pinion thrust washers.

4.4.	Remove the differential side gears and the side gear thrust washers.

Mark the pinion gears top and bottom and the differential side gears left and right.

1. Lubricate all the parts using axle lubricant. Refer to Fluid and Lubricant Recommendations in Maintenance and Lubrication.
2. Install the thrust washers to the differential side gears.
3. Install the differential side gears and thrust washers into the differential case.

If the same differential side gears and the thrust washers are being used, install the gears and the thrust washers to the original locations.

4. Install the differential pinion gears by doing the following:

4.1.	Position one pinion gear between the differential side gears.

4.2.	Rotate the differential side gears until the pinion gear is directly opposite the opening in the differential case.

4.3.	Place the other pinion gear between the differential side gears.

Line up the hole in both the pinion gears.

5. Install the thrust washers.

Rotate the pinion gears toward the opening in order to permit the sliding in of the thrust washers.

6. Install the pinion shaft.

Notice: Refer to Fastener Notice in the Preface section.

7. Install a new pinion shaft lock bolt.

Tighten

•	For the 8.6 inch axle, tighten the pinion shaft lock bolt to 36 N·m (27 lb ft).

•	For the 9.5 inch axle, tighten the pinion shaft lock bolt to 50 N·m (37 lb ft).





Important: The mating surface of the ring gear and the differential case must be clean and free of burrs before installing the ring gear.

8. Install the ring gear to the differential case.




Important: The ring gear bolts have left-hand threads.

9. Install the new ring gear bolts.

Hand start each bolt to ensure that the ring gear is properly installed to the differential case.

10. Tighten the new ring gear bolts. Tighten the ring gear bolts alternately and in stages, gradually pulling the ring gear onto the differential case.

Tighten

•	For the 8.6 inch axle, tighten the ring gear bolts in sequence to 120 N·m (89 lb ft).

•	For the 9.5 inch axle, tighten the ring gear bolts in sequence to 140 N·m (103 lb ft).

11. Install the differential side bearings. Refer to Differential Side Bearings Replacement .

Differential Overhaul 11 Inch Axle

Tools Required

Important: Mark the side bearings, the outboard shims, and the bearing cups appropriately and place with the corresponding bearing cap.

1. Remove the differential side bearings using the J 8107-2 , the J 29721 and the J 29721-70 .

Important: Mark the inboard spacer left or right and place with the corresponding bearing cup and bearing cap.

2. Remove the inboard spacer.



3. Remove the ring gear bolts.

Discard the ring gear bolts.

Notice: Do not pry the ring gear from the case. This will damage the ring gear and differential case.

4. Remove the ring gear from the differential case assembly.



5. Remove the pinion shaft lock pin using a hammer and a punch.



6. Remove the pinion shaft using a hammer and brass drift.




Important: Mark the pinion gears and the thrust washers top and bottom.

7. Rotate the side gears until the pinion gears are in the opening of the case. Remove the pinion gears and thrust washers.

Important: Mark the side gears and the thrust washers left and right

8. Remove the side gears and the thrust washers.

1. Lubricate all parts with an axle lubricant (GM P/N 12346140 or equivalent).
2. Install new thrust washers to the side gears.

Important: Install the side gears to the same side that the side gears were on when removed.

3. Install the side gears to the differential case assembly.

Important: Install the pinion gears to the same side that the pinion gears were on when removed.

4. Install the pinion gears to the differential without the thrust washers.

4.1.	Install the pinion gears to the side gears so that the holes in the pinion gears are 180 degrees apart.

4.2.	Rotate the pinion gears into place. Verify that the pinion gears line up with the pinion shaft holes.

5. Rotate the pinion gears toward the differential opening in order to allow enough space for the pinion gear thrust washers to slide in.
6. Install the new pinion gear thrust washers.
7. Rotate the pinion gears into place. Verify that the pinion gears line up with the pinion shaft holes.
8. Install the pinion shaft.
9. Align the pinion shaft lock pin hole with the hole in the differential case assembly and the pinion shaft.



10. Install the new pinion shaft lock pin.
11. Peen the metal from the case over the pinion shaft lock pin in two places that are 180 degrees apart.




Important: The mating surface of the ring gear and the differential case assembly must be clean and free of burrs before installing the ring gear.

12. Install the ring gear to the differential case assembly.

Align the holes in the differential case assembly and the holes in the ring gear.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

13. Install new ring gear bolts. Tighten the ring gear bolts alternately and in stages, gradually pulling the ring gear onto the differential case assembly.

Tighten
Tighten the ring gear bolts in sequence to 298 N·m (220 lb ft).

Important: The spacer must be the same size as the spacer that was removed.

14. Install one new hardened 0.689-0.838 mm (0.027-0.033 in) inboard spacer onto each side of the differential case assembly.

Measure the spacer thickness using a micrometer to verify the spacer size.




15. Install the differential side bearings using the J 23690 and the J 8092 .

Differential Overhaul 10.5 Inch Axle

1. Remove the differential side bearings. Refer to Differential Side Bearings Replacement .




Important: The ring gear bolts have left-hand threads.

2. Remove the ring gear bolts.

Notice: Refer to Ring Gear Removal Notice in the Preface section.

3. Remove the ring gear from the differential case.

Drive the ring gear off with a brass drift if necessary.

4. Separate the differential case assembly.




Important: If the differential pinion gears, the differential side and the thrust washers are to be reused, mark the components so they can be re-installed in their original location in the differential case.

5. Remove the following from the differential case:

•	The thrust washers

•	The differential pinion gears

•	The differential pinion spider




6. Remove the differential side gears.

1. Lubricate the differential side gears and the differential pinion gears with axle lubricant. Use the proper fluid. Refer to Fluid and Lubricant Recommendations in Maintenance and Lubrication.



2. Install the differential side gears into the differential case.

If the original differential side gears are being used, install the gears in the original location.




3. Assemble the differential pinion gears and the thrust washers to the differential spider as shown.

If the original differential pinion gears, the thrust washers and the differential spider are being used, install the components in the original locations.




4. Assemble the differential case halves.

Align the arrow in the differential case as shown.

Important: The mating surface of the ring gear and the differential case must be clean and free of burrs before installing the ring gear.

5. Install the ring gear to the differential case.

Notice: Refer to Fastener Notice in the Preface section.




6. Install the new ring gear bolts.

Hand start each bolt in ensure the ring gear is properly installed to the differential case.

7. Tighten the ring gear bolts. Tighten the bolts alternately and in stages, gradually pulling the ring gear onto the differential case.

Tighten
Tighten the ring gear bolts in sequence to 165 N·m (122 lb ft).

8. Install the differential side bearings. Refer to Differential Side Bearings Replacement .