Adjusting Backlash

NOTE:
^ The pinion must be adjusted and installed with shim S3.
^ Compensation: S1 (variable value) on the cover side and S2* 0.00 mm) on the housing side.

- Install differential gear in axle housing, install cover and tighten all bolts to 25 Nm 0 8 ft lb).
- Turn differential gear several times in each direction so tapered roller bearings settle.





- Install measuring tools.
- Use dial indicator extension VW 382/10 (6 mm flat).
- Set measuring lever "a" to 60 mm.
- Turn ring gear to stop and set dial indicator to zero.
- Turn ring gear back and read and record backlash.
Each time the ring gear is turned 901:
- Carry out measurement three more times.
- Add up four measurements and calculate average backlash.

NOTE: If during this measurement, the individual values determined vary by more the 0.06 mm from each other, the installation of the ring gear or the ring gear and pinion set itself is not OK. Check the installation sequence. If necessary, replace the ring gear and pinion set.

Determining Average Backlash
Example:
1st measurement 0.28 mm
2nd measurement + 0.30 mm
3rd measurement + 0.30 mm
4th measurement + 0.28 mm ______________________________________
Total = 1.16 mm

Average backlash:
1.16mm divided by 4 = 0.29 mm

Determining Shim Thickness "S2" (correction Of Shim Thickness S2*)
Housing Side

S2 = S2* - average backlash
+ lift (constant value)

Lift = 0.15 mm

Example:
S2* 1.00 mm
Average backlash - 0.29 mm
Lift (constant value) + 0.15 mm ______________________________________
= S2 = 0.86 mm

Shims supplied as replacement parts, refer to parts supplier

Determine Shim Thickness "S1"
Ring Gear Side

S1 = Stotal -S2

Example:
Stotal 1.90 mm
-S2 0.86 mm ______________________________________
=S1 1.04 mm

Different shim thicknesses make it possible to obtain the required shim thickness precisely. Shims S1 and S2 supplied as replacement parts, refer to parts supplier.

- Install shims determined, if necessary use 2 shims.
Shim S1 is installed on ring gear side
Shim S2 is installed on housing side

Checking Measurement
- Install differential gear in axle housing, install cover and tighten all bolts to 25 Nm (18 ft lb).
- Turn differential gear several times in each direction so tapered roller bearings settle.





- Install measuring tools.
- Measure backlash four times throughout rotation.
Specification: 0.12-0.22 mm
- If backlash is not correct (0.12-0.22 mm), the adjustment procedure has to be repeated. The total shim thickness "Stotal" must not change.

NOTE: The individual measurements must not deviate from each other by more than 0.06 mm.