Ring Gear, Adjusting
Ring Gear, Adjusting
Adjusting Differential
For a list of the repairs which will require the ring gear to be adjusted List of Adjustments
Special Tools And Equipment
- VW382/10 Dial Indicator Extension
- VW385/17 Magnetic Plate
- VW387 Dial Gauge Holder
- VW388 Measuring Lever
- VW402 Thrust Plate
- VW408A Punch
- VW472/1 Pressure Piece
- VW521 Adjustment Tool
- 3177 Clamp
- Torque Gauge 0-600 Nm
- Dial Indicator
- Dial Indicator Extension 30 mm
Determining total shim thickness Stotal for shims S1 + S2
(Adjust preload of tapered roller bearing for differential)
- Pinion shaft removed
Note:
- If only the differential tapered roller bearings are to be replaced, remove ring gear from differential housing. The pinion shaft does not have to be removed.
- Remove seals and outer races from both tapered roller bearings for differential.
- Remove shims, Differential, Disassembling and Assembling
- Drive in tapered roller bearing outer race together with shim S2 into transmission housing. Fig. 3 Install Right Bearing Outer Race In Transmission Housing Use shim S2* with 1.20 mm thickness for measurement purposes (2 shims with 0.60 mm).
Note:
- A shim S2 with a thickness of 1.20 mm is installed for initial measurement. It is referred to in the following text as S2*.After determining backlash, S2* is replaced with the appropriate shim S2.
- Press in tapered roller bearing outer race into differential cover without shim S 1. Fig. 9 Driving In Left Bearing Outer Race Into Cover
- Install differential into transmission housing without Vehicle Speed Sensor (VSS) -G22- gear drive. Ring gear is located on left side in front of final drive cover.
- Install cover for differential and tighten four bolts to 25 Nm (18 ft. lbs.).
- Position transmission so that cover for differential faces upward.
- Turn differential 5 rotations in each direction to seat tapered roller bearing.
- Assemble measuring equipment use 30 mm dial indicator extension.
- Set dial indicator (3 mm measuring range) -A- to O with 2mm preload.
Note:
- Tip of dial indicator must be positioned on the center of the differential.
- Lift differential without turning it, read play on dial indicator and note.
- Dimension in the following example: 0.62 mm
Notes:
- To lift differential, secure VW521/4 locking sleeve and VW521/8 bushing (for transmissions without polygon bearing) or VW521112 (for transmissions with polygon bearing) to right side of differential (housing side).
- If measurement has to be repeated, turn differential again 5 rotations in both directions to seat tapered roller bearing.
Formula:
Stotal = S2* - measured value bearing preload
Example:
Installed shim S2* 1.20 mm
+ Dimension 0.62 mm
+ Bearing preload (constant) 0.30 mm __________
= Total shim thickness S total for S1 + S2 2.12 mm
* Pinion shaft removed.
Determining thickness of shim S1*
Notes:
- S1 is used for the initial measurement. After determining backlash, S1* is replaced with final shim S1.
- The total shim thickness Stotal remains unchanged.
Formula:
S1* = Stotal - S2*
Example:
Total shim thickness Stotal for S1 + S2 2.12 mm
- Installed shim S2* 1.20 mm __________
= Thickness of shim S1* 0.92 mm
* Pinion shaft removed.
Measuring friction torque (check measurement)
Notes:
- Tapered roller bearings for differential are low-friction. Measurement of friction torque only has a limited use as a check. Correct adjustment is only possible by determining the tote/ shim thickness "Stotal."
- Do not lubricate new tapered roller bearings for measuring friction torque. The bearings have already been treated by a special oil by the manufacturer.
- Pinion shaft removed
- Install torque gauge 0-600 Nm -A- on differential.
- Read friction torque.
- Friction torque specified values:
New Bearing Used Bearing
200 - 350 Ncm 30 - 60 Ncm
Note:
- For a readjustment of the gear set, the pinion shaft adjustment should now be checked. Pinion Shaft, Adjusting
Measuring backlash
(Position of ring gear in transmission housing)
- Pinion shaft with shims S3* and S4* installed
- Install differential.
- Turn differential 5 rotations in each direction to seat tapered roller bearing.
- Secure VW387 dial gauge holder on housing.
- Install VW521/4 locking sleeve and VW521/8 bushing (for transmissions without polygon bearing) or VW521/12 (for transmissions with polygon bearings).
- Install dial indicator with VW382/10 extension pin, 6 mm.
Dimension "a" Ring Gear Diameter
67 mm 170 mm
72 mm 180 mm
- Set VW388 measuring lever to dimension "a:"
- Determine play between teeth flanks as follows:
- Turn ring gear until it contacts a tooth flank (end of backlash travel).
- Set dial indicator to O with 2 mm preload.
- Turn ring gear back until it contacts opposite tooth flank (backlash).
- Read backlash and note.
- Turn ring gear another 90° and repeat measurement 3 times.
Notes:
- If pinion shaft turns when fuming differential, install 3177 clamp -A- so that an exact backlash measurement can be made.
- Loosen clamping piece to turn the ring gear further.
- Differential must be installed with cutout for differential bevel gears facing pinion shaft.
- If 3177 clamp is installed, install differential 180° to final position and repeat measurements.
Determining average backlash
Add four measured values together and divide total by 4 to determine average.
Example:
1st Measurement 0.28 mm
+ 2nd Measurement 0.30 mm
+ 3rd Measurement 0.30 mm
+ 4th Measurement 0.28 mm __________
Total of measurements 1.16 mm
Result: The average backlash is 1.16 mm divided by 4 = 0.29 mm
Note:
- If the measured values differ more than 0.06 mm from each other, the installation of ring gear or gear set itself may not be correct. Check installation and replace gear set if necessary.
Determining thickness of shim S2
Formula:
S2 = S2* - backlash - lift
Example:
Installed shim S2* 1.20 mm
- Average backlash 0.29 mm
+ Lift (constant) 0.15 mm __________
= Thickness of shim S2 1.06 mm
- Determine shim(s) according to table.
- Available shims for S2
- Shim Thickness (mm) (1)
0.45 0.65 0.85
0.50 0.70 0.90
0.55 0.75
0.60 0.80
(1) Using shim tolerances it is possible to find the exact shim thickness required; insert two shims if necessary.
Determining thickness of shim S1
Formula:
S1 = Stotal - S2
Example:
Total thickness Stotal for S1 + S2 2.12 mm
- Thickness of shim S2 1.06 mm __________
= Thickness of shim S1 1.06 mm
- Determine shim(s) according to table.
Available shims for S1
- Shim Thickness (mm) (1)
0.45 0.65 0.85
0.50 0.70 0.90
0.55 0.75
0.60 0.80
(1) Using shim tolerances it is possible to find the exact shim thickness required; insert two shims if necessary.
Checking measurement
- After installing shims S1 and S2, turn differential 5 rotations in each direction to seat tapered roller bearings.
Note:
- For transmissions without polygon bearing, use VW52118 bushing instead of VW521112 shown.
- Measure backlash 4 times on circumference.
Specification: 0.12 - 0.22 mm
Notes:
- If backlash lies outside tolerance, repeat adjustments. Do not change total shim thickness Stotal.
- The individual measurements must not vary more than 0.06 mm from each other.