Differential: Adjustments: Overview

Pinion shaft and ring gear, adjusting
General notes
Careful adjustment of the ring gear and pinion shaft is essential to ensure that the final drive gives long service and runs silently. During manufacture the ring gear and pinion shaft are matched and checked on testing machines to ensure correct mesh pattern and silent running. The position for quietest running is obtained by moving the pinion shaft axially and, at the same time, maintaining the backlash within the specified tolerances.
The deviation "r" from the master gauge "Ro" is marked on the ring gear. Only replace gear set (ring gear and pinion shaft) together!

Gear sets, adjusting and marking





1. Identification " 0937" signifies Oerlikon gear set with a ratio of 37:9.
2. Gear set pairing number (31 2).
3. Deviation (tolerance) "r" is based on the test machine master gauge used in the production. The deviation "r" is always given in 1/100 mm.
Example: "25" signifies r = 0.25 mm
Ro - Length of test machine master gauge used "Ro".
Ro - Ring gear 0170 mm = 54.95 mm
Ro - Ring gear 180 mm = 59.65 mm
R - Actual dimension between ring gear and face of pinion shaft at point with quietest running for this gear set.
Vo - Hypoid offset

Shims, position





S1 - Shim for ring gear in final drive housing cover
S2 - Shim for ring gear in transmission housing
S3 - Shim for pinion shaft in transmission housing
S4 - Shim for pinion shaft in transmission cover

Adjustment overview

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Note: If repairs have been carried out to the transmission it is only necessary to adjust the ring gear, pinion shaft or complete gear set if components have been replaced which have a direct effect on the adjustment of the final drive. Refer to the table to avoid unnecessary adjustment.

1) If the transmission housing is changed the input shaft must also be adjusted.

Gear set, recommended adjusting sequence
When ring gear and pinion shaft have to be adjusted, in the interests of a rational sequence, keep to the following order:





- Determine total shim thickness "S_total" (S1 plus S2) to give specified preload on differential taper roller bearings.
- Determine total shim thickness "S_total" (S3 plus S4) for the specified preload on pinion shaft taper roller bearings.
- Distribute total shim thickness "S_total" (S3 plus S4), so that the dimension from the center of the ring gear to the face of the pinion shaft corresponds to the dimension "R" determined during production.
- Distribute total shim thickness "S_total" (S1 plus S2) so that the specified backlash between ring gear and pinion shaft is achieved.
The aim of this adjustment is to re-attain the position, which offers the quietest running as calculated on the test machine during production. The utmost care and cleanliness during all assembly work and measurements is essential to achieve a good result.