Gear Tooth Contact Pattern Inspection: Notes
WARNING: This page is about a different car, the 2003 GMC Safari and 2003 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
The gear contact pattern check is not a substitute for adjusting the pinion depth and backlash. Use this method in order to verify the correct running position of the ring gear and the drive pinion. Gear sets which are not positioned properly may be nosy and/or have a short life span. A pattern check ensures that when beat contact has been obtained between the ring gear and the drive pinion, the system will produce low noise and have a long life.