Contact Pattern Adjustment

Backlash and position of drive pinion in differential carrier are the only two adjustments which can be made that will affect the contact pattern. The effects of bearing preload adjustments are not readily apparent with tooth pattern checks. However, these adjustments should be within specifications before proceeding with backlash and drive pinion adjustments.

The drive pinion position is adjusted by increasing or decreasing the shim thickness between the pinion head and inner race of rear bearing. Increasing the shim thickness will move the pinion closer to center line of ring gear. Decreasing shim thickness will move pinion farther away from center line of ring pinion.

Backlash is adjusted by means of the side bearing adjusting shims which moves the entire case and ring gear assembly closer to or further away from the drive pinion. To increase backlash, increase right shim and decrease left shim an equal amount. To decrease backlash, decrease right shim and increase left shim an equal amount.

It may be necessary to adjust both pinon depth and backlash to obtain the correct pattern.