Backlash, Adjusting

Note:
- The pinion should be installed with shim S3.
- Adjustment S1 (variable value) installed on cover side and S2 (1.00 mm) installed on housing side.

- Rotate differential several times in both directions to enable tapered roller bearings to seat.
- Install differential in housing, install cover and bolt down completely.





- Install measuring tools.
- Use dial indicator extension VW 392/10 (6 mm flat).
- Set measuring lever to -a- = 60 mm.
- Turn ring gear as far as stop; set dial indicator to zero.
- Turn ring gear back, read and record backlash measurement.
- Repeat measurement three times, turning ring gear 901 for each measurement. Add together four readings and calculate average backlash.

Note:
If the individual readings obtained during this measurement differ by more than 0.06 mm from each other, either the ring gear or the drive gear set itself is out of alignment. Check installation work, replace drive gear set if necessary

Determining average backlash





Example:

Average torsional backlash = 1.16 mm/4 = 0.29 mm

Determining thickness of shim "S2" (Correction to measurement - shim thickness S2*)

Housing side
S2 = S2
- average torsional backlash
+ lift (constant value)
Lift = 0.15 mm





Example:

See parts catalog for replacement shims.

Determining thickness of shim S1
Ring gear side

S1 = S(total) - S2





Example:

See parts catalog for replacement shims.

Note:
- The tolerances in nominal shim sizes make it possible to choose a shim with the precise thickness required for S1.
- Install shims, S 1 on ring gear side and S2 on housing side. If necessary 2 shims can be used.

Checking measurements
- Install differential in housing.
- Install cover and bolt completely.
- Turn differential several times in both directions to seat tapered roller bearings.
- Install measuring tools.
- Measure backlash four times around circumference.
- backlash must be 0.12 - 0.22 mm
- If backlash is not correct (0.12 - 0.22 mm) adjustment procedure must be repeated. Total shim thickness "S(total)" must not change.

Note:
Individual test results may deviate by max. 0.06 mm.