Right Side Gear Backlash Adjustment

1. If necessary, remove the following from the differential case:
   1. The pinion lock shaft bolt
   2. The pinion shaft
   3. The differential pinion gears
   4. The differential pinion gear thrust washers
   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:  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.

Fig 1: Installing Brass Drift Between Locking Differential Side Gear & Pinion Shaft
Courtesy of GENERAL MOTORS CORP.
9. Measure the backlash of the pinion gear and the right side gear by doing the following:
   1. Install the J 7872  (1) to the ring gear flange.
   2. Loosely clamp the J 8001-3 (2) onto the stem on the J 7872  (1).
   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.

   4. Tighten the lock nut of the J 8001-3 finger tight.
   5. Pull the pinion gear firmly into the differential case seat.
   6. Rotate the pinion gear back and forth.
   7. Measure the backlash.

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

Fig 2: Measuring Backlash Of Differential Pinion Gear & Side Gear
Courtesy of GENERAL MOTORS CORP.
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: 

• 0.254 mm (0.010 in)
• 0.381 mm (0.015 in)
• 0.508 mm (0.020 in)
• 0.635 mm (0.025 in)
• 0.762 mm (0.030 in)
• 0.889 mm (0.035 in)
• 1.016 mm (0.040 in)
• 1.143 mm (0.045 in)