Differential Carrier Bearing Preload Adjustment. Pontiac Sun Runner - 4WD (Canada) 1998

For 1990-2009 cars

The side bearing preload is necessary to maintain the correct bearing pressure on both sides of the differential case so that the differential case will turn evenly at all speeds. The side bearing preload is measured by the distance between the side bearing caps or the case spread. Once the differential side bearing preload has been adjusted, it must be maintained throughout the differential backlash adjustment procedure.

Setting differential backlash is very important to the service life of the ring and pinion gears. Setting the differential backlash determines the amount of depth at which the ring gear will contact the pinon gear. This determines the distance of the pinion gear teeth from the drive side and the coast side of the ring gear teeth. The deeper the gears mesh, the less the amount of the backlash. The more shallow the mesh, the more backlash is created. This adjustment is vital for correct differential operation.

#### Tools Required

• | J 3289-20 Holding Fixture Base

• | J 3289-21 Holding Fixture

• | J 37769 Differential Holding Fixture Adapters

• | J 37760 Spanner Wrench

• | J 8001 Dial Indicator Set

1. Loosen the left differential side bearing adjuster using the J 37760 until it no longer makes contact with the left differential side bearing race.
2. Tighten the right differential side bearing adjuster using the J 37760 until the ring gear is fully engaged with the pinion gear (0.000 backlash).
3. Inspect the left adjuster. Verify that the left adjuster is not making contact with the left differential side bearing race.
4. Inspect the pinion gear for binding by grasping the pinion flange and rotating the pinion gear several times.
5. Install the J 8001 on the differential carrier between the center of each side bearing cap and load slightly to measure the case spread.
6. Tighten the left differential side bearing adjuster using the J 37760 until the adjuster makes contact with the right side bearing race.
7. Rotate the J 8001 adjustable face so that the needle indicates 0.
8. Adjust the side bearing preload by tightening the left differential side bearing adjuster using the J 37760 until the J 8001 reads 0.0508 to 0.1524 mm (0.002 to 0.006 in). This specification indicates the amount of case spread between the centers of both side bearing caps.