Left Side Gear Backlash Adjustment

Fig 1: View Of Left Side Gear Thrust Washer
Courtesy of GENERAL MOTORS CORP.
1. Install the new left side thrust washer into the flange end of the differential case.
Fig 2: View Of Left Side Gear Cam Unit & Clutch Disc Assembly
Courtesy of GENERAL MOTORS CORP.
2. Install the left side gear (cam unit) and clutch pack assembly into the differential case.
3. Install the pinion gears with the pinion thrust washers into the differential case.

   Align the openings of the pinion gears and the pinion 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 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 side gear thrust washer with a thinner washer.

NOTE: Refer to Fastener Notice in Cautions and Notices.
5. Install the pinion shaft lock bolt.

   Tighten:  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.

Fig 3: Measuring Backlash Of Differential Pinion Gear & Side Gear
Courtesy of GENERAL MOTORS CORP.
8. Measure the backlash of the pinion gear and the side gear by doing the following:
   1. Install the J 7872  (1) to the ring gear flange. See Special Tools and Equipment .
   2. Loosely clamp the J 8001-3  (2) onto the stem on the J 7872  (1). See Special Tools and Equipment .
   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.

      Tighten:  Tighten the lock nut of the J 8001-2  finger tight.

   4. Pull the pinion gear firmly into the differential case seat.
   5. Rotate the pinion gear back and forth.
   6. Measure the backlash.

      Specification:  The backlash for the pinion gears should be 0.000-0.076 mm (0.000-0.003 in).

9. If the backlash is too large, install a thicker side gear thrust washer and inspect the backlash.
10. If the backlash is too small, install a thinner side gear thrust washer and inspect the backlash.

Left side gear thrust washers are available in the following sizes:

Washer Sizes: 

• 0.56 mm (0.022 in)
• 0.68 mm (0.027 in)
• 0.81 mm (0.032 in)
• 0.91 mm (0.036 in)
• 1.02 mm (0.040 in)
• 1.12 mm (0.044 in)
• 1.22 mm (0.048 in)
• 1.32 mm (0.052 in)