Backlash Inspection and Adjustment

Special Tools

• J 8001  Dial Indicator Set
• J 45224  Side Bearing Adjuster

1. Mark the location of the differential adjuster nut sleeves in relation to the differential carrier halves.

   Ensure that the notches can be counted when turned.

Fig 1: Measuring Ring Gear Backlash
Courtesy of GENERAL MOTORS COMPANY
2. Install the J 8001-1 (1, 2), the J 8001-2 (3), and the J 8001-3 (4) as shown.

   Ensure that the button contacts the outer edge of the pinion yoke and that the plunger is at a right angle to the pinion yoke.

3. Move the pinion yoke back and forth through the pinion flange's free play while not allowing the ring gear to move.
4. Record the dial indicator reading.
5. To determine the actual backlash, divide the dial indicator reading by 2.

   An actual dial indicator reading of 0.16 mm (0.006 in) means that there is actually 0.08 mm (0.003 in) backlash.

   Specification 

   The backlash between the ring gear and the drive pinion should be between 0.08-0.25 mm (0.003-0.010 in) with a preferred specification of 0.13-0.18 mm (0.005-0.007 in).

IMPORTANT:
When adjusting the backlash, observe the following:
• Always turn the left and the right differential adjuster nut sleeves in equal amounts.
• Turning the differential adjuster nut sleeves one notch will change the backlash about 0.08 mm (0.003 in).
6. If the backlash is too small, increase the backlash by turning the left differential adjuster nut sleeve in one notch and the right differential adjuster nut sleeve out one notch using the J 45224  Side Bearing Adjuster.
7. If the backlash is too large, decrease the backlash by turning the right differential adjuster nut sleeve in one notch and the left differential adjuster nut sleeve out one notch using the J 45224  Side Bearing Adjuster.
8. Recheck the backlash and adjust as necessary.
9. Recheck the rotating torque of the pinion and differential assembly and adjust as necessary.
10. Once the backlash and rotating torque of the pinion and differential assembly is correct, perform a gear tooth contact pattern check to ensure proper contact between the pinion and the ring gear. Refer to Gear Tooth Contact Pattern Inspection .
11. Once the pinion and differential side bearing preload, the backlash, and the gear tooth contact pattern is within specifications, complete the assembly of the differential carrier assembly. Refer to Differential Carrier Assembly Final Assembly .