Adjustments Affecting Tooth Contact

Two adjustments can be made that affects tooth contact pattern; backlash and pinion depth. The effects of bearing preloads are not readily apparent on hand loaded tooth contact pattern tests. However, these adjustments should be within specifications before proceeding with backlash and drive pinion adjustments.

The position of the drive pinion is adjusted by increasing or decreasing the distance between the pinion head and the centerline of the ring gear. Decreasing the distance will move the pinion closer to the centerline of the ring gear. Increasing the distance will move the pinion farther away from the centerline of the ring gear.

Backlash is adjusted using side bearing adjusting shims that move the entire case and ring gear assembly closer to or farther from the drive pinion. The adjusting shims are also used to set side bearing preload.

If the thickness of the right shim is increased (along with decreasing the left shim thickness), backlash will increase.

If the thickness of the left shim is increased (along with decreasing the right shim thickness), backlash will decrease.