Testing Procedure

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Wipe clean the differential case, the ring gear and the axle housing of lubricant. Carefully clean each tooth of the ring gear.
Use a medium stiff brush in order to sparingly apply gear marking compound, GM P/N 1052351 (Canadian P/N 10953497) or equivalent, to all of the ring gear teeth.
Torque the bearing caps bolts to specification.
IMPORTANT: Performing a test without loading the gears will not produce a satisfactory pattern.
Apply the park brake until a torque load of 14 N.m (10 lb ft) is required in order to turn the pinion.
IMPORTANT: Avoid turning the ring gear excessively.
Using a wrench, turn the drive pinion flange/yoke so that the ring gear rotates 3 full revolutions.
Turn the drive pinion flange/yoke in the opposite direction so that the ring gear rotates 3 full revolutions in the opposite direction.
Observe the pattern on the ring gear teeth. Compare the pattern with the following illustrations.

Fig 1: Clean Gear With Medium Stiff Brush
Courtesy of GENERAL MOTORS CORP.