Ring Gear, Adjusting

Determining total shim thickness "S(total)" (S1 + S2)

Note:
- The ring gear must be adjusted only if the following components have been replaced. final drive housing, final drive cover, differential tapered roller bearings, differential housing or gear set List of adjustments. List of Adjustments
- Either remove the pinion to adjust the ring gear or the ring gear must be removed from the differential.
- The differential tapered roller bearings are friction-free. Therefore, the friction torque is used only as a control measurement. A correct adjustment is possible by determining the total shim thickness "S item-17-.
- When measuring new tapered roller bearings for friction torque, additional oil is not necessary

- Remove seal and outer races for differential tapered roller bearings and remove shims.
- Drive in tapered roller bearing outer races -without shims- as far as possible.
- Install differential in housing.
The ring gear is on the right-hand side (cover side).
- Install differential cover and tighten alternate cover bolts in a diagonal pattern to 24 Nm (18 ft lb).
- Turn cover side up.
- Install special tool VW521/4 andVW521/8on housing side of final drive housing.
- Place VW 385/17 on differential.

Note:
Turn differential several times in both directions to seat the tapered roller bearings.





- Install measuring tools.
A= Dial indicator extension approx. 30 mm long
B= M8 x 45 hex bolt
- Place dial indicator extension in center of measuring plate.
- Set dial indicator (3 mm range) to zero with 1 mm preload.





- Move differential up and down; read and record play on dial indicator.
Example: 1.60 mm

Determining "Stotal" (S1 + S2)
S(total) = Dial indicator reading + preload





Example:

- Install calculated total shim thickness (1.90 mm in example) behind tapered roller bearing outer race in final drive housing (S2 side).





Example:

Note:
- Pre-adjustment value is 1. 00 for quick estimate of torsional backlash.
- Total shim thickness Stotal must be maintained.
- Check parts catalog for replacement shims.





- Measure friction torque





A= Commercial torque gauge, 0 - 600 Ncm

Note:
- The differential tapered roller bearings are friction-free. Therefore, the friction torque is used only as a control measurement A correct adjustment is possible by determining the total shim thickness "Stotal ".
- When measuring new tapered roller bearings for friction torque, additional oil is not necessary.
- When re-adjusting the gear set, the drive pinion adjustment with checking measurements should be done now.