Ring Gear, Adjusting
Adjusting differential
The ring gear must be adjusted if any of the components have been replaced, Refer to List of Adjustments.
Notes:
- Differential tapered roller bearings are low friction bearings. Therefore the friction torque only has a limited use as a check. Correct adjustment is only possible by determining the total shim thickness Stotal.
- Do not additionally oil new tapered roller bearings for the friction torque measurement. The bearings have already been treated with a special oil by the manufacturer.
Determining total shim thickness "Stotal" for shims S1 + S2
(Setting preload of tapered roller bearing for differential)
5Pinion shaft removed or ring gear removed from differential housing.
- Pry out drive flange seal using pry bar.
- Remove differential tapered roller bearing outer races and remove shims, Refer to Differential Assembly, Service and Repair.
- Press left tapered roller bearing outer race for differential (housing side) with shim S2 into housing. To perform the measurement use shim S2* with thickness of 1.00 mm (one 0.80 mm shim and one 0.20 mm shim).
Note: For measurement specification, a shim S2 of 1.0 mm thickness is initially inserted which will be designated S2*. After determining the backlash S2* will be replaced by the correct shim S2.
- Press in right tapered roller bearing outer race for differential (final drive cover side) without shims, until stop.
- Insert differential into housing. Ring gear is positioned on right side (cover side).
- Install final drive cover and tighten bolts to 25 Nm (18 ft. lbs.).
- Install special tools VW521/4 locking sleeve and 521/8 bushing on housing side into differential housing.
- Turn final drive housing so final drive cover faces upward.
- Turn differential 5 turns in both directions to settle tapered roller bearing.
- Place VW385/17 magnetic plate onto differential.
- Install measuring tools.
A - Dial indicator extension approx. 30 mm long
B - Hex-head bolt M8 x 45
- Place dial indicator extension on center of VW385/17 magnetic plate.
- Set dial indicator (3 mm measuring range) to "O" with 2 mm preload.
- Lift up differential without turning; read off play on dial indicator and note.
Measurements in the example: 0.50 mm
Note: If the measurement has to be repeated, the differential must again be turned 5 turns in each direction to settle the tapered roller bearing.
Formula:
Example:
Determining thickness of shim "S1*"
Notes:
- The preliminary shim S1* will be replaced with the final shim S1 after determining the backlash.
- The total shim thickness Stotal remains unchanged.
Formula:
Example:
- Determine shim(s) according to table, Determining thickness of shim "S1".
Measuring friction torque
- Pinion shaft removed
- Differential with shims S1* and S2* installed
- Install torque gauge, 0 - 600 Nm (53 inch lbs.) A- onto differential.
- Read value of dial indicator.
Friction torque specifications:
1) Must have run at least 50 km (30 miles)
Notes:
- Differential tapered roller bearings are low friction bearings. Therefore the friction torque only has a limited use as a check. Correct adjustment is only possible by determining the total shim thickness Stotal.
- Do not additionally oil new tapered roller bearings for the friction torque measurement. The bearings have already been treated with a special oil by the manufacturer.
- If the final drive gear set (pinion shaft and ring gear) is being re-adjusted, the adjustment of the pinion shaft should be checked, Refer to Pinion Shaft, Adjusting.
Adjusting backlash
Position of ring gear in final drive housing
- Pinion shaft with shim S3 installed
- Differential with shims S1* + S2* installed
- Insert differential into final drive housing, install final drive cover and tighten all bolts to 25 Nm (18 ft. lbs.).
- Turn differential 5 turns in both directions to settle tapered roller bearings.
- Assemble measuring equipment.
- Use VW382/10 dial indicator extension (6 mm flat).
- Set VW388 measuring lever to dimension -a
Dimension -a-: 60 mm.
- Determine play between teeth flanks as follows:
- Turn ring gear until it makes contact with tooth flank (end of backlash travel).
- Set dial indicator to "O" with 1 mm preload.
- Turn ring gear back until contact is made against opposite tooth flank (backlash).
- Read value of dial indicator and note.
- Turn ring gear 1/2-turn (90°) each time and repeat measurements 3 times.
CAUTION: If the individual measurements differ by more than 0.06 mm from each other, the installation of the ring gear or the final drive set itself is not correct Check installation, replace final drive set if necessary.
Determining average backlash
Example:
Determining thickness of shim "S2"
Formula:
Example:
- Determine shim(s) according to table. Part numbers, Refer to Parts Supplier.
The shims are available for "S2"
Determining thickness of shim "S1"
Formula:
Example:
The shims are available for "S1"
Checking measurements
- Pinion shaft with shim S3 installed
- Differential with shims S1 + S2 installed
- Turn differential 5 turns in both directions to settle tapered roller bearings.
- Measure backlash four times on circumference.
Specifications: 0.12 - 0.22 mm
Notes:
- If the backlash lies outside the tolerance, the adjustment must be repeated, but the total shim thickness Stotal must remain unchanged.
- The individual measurements must not differ by more than 0.06 mm from each other.