Crown Wheel, Adjusting
Crown wheel, adjusting - 6 Spd. M/T 01X Front Wheel Drive
(Adjusting differential)
Special tools, testers and auxiliary items required
^ Drift VW 295
^ Dial gauge extension VW382/10
^ End measuring plate VW385/17
^ Universal dial gauge bracket VW387
^ Adjustable measuring lever VW 388
^ Thrust plate VW402
Special tools, testers and auxiliary items required
^ Press tool VW408A
^ Crown wheel adjusting tool VW 521
^ Tube 30 - 14
^ Thrust piece 2050
^ Thrust plate 3005
^ Torque wrench V.A.G1331
^ Dial gauge
^ Dial gauge extension, 30 mm
It is necessary to readjust crown wheel when the following components have been replaced:
Transmission housing, final drive cover, taper roller bearings for differential, differential cage or the final drive gear set
Table of adjustments
Determining total shim thickness "Stotal" for shims "S1" plus "S2"
(adjustment of pre-load of taper roller bearings for differential)
^ Pinion shaft removed
- Remove flange shaft oil seals
- Remove tapered roller bearing outer races for differential and remove shims.
- Drive outer race for tapered roller bearing (right-side) with shim "S2" into transmission housing. For measurement purposes use a 1.30 mm thick "S2*" shim (or 2 shims of 0.65 mm).
Note:
^ For measurement purposes a 1.30mm thick shim "S2" is inserted provisionally. This is referred to in the following as "S2*". "S2*" is exchanged with the final shim "S2" after determining backlash.
- Press tapered roller bearing outer race (left-side) without shim "S1" into cover for final drive.
- Install differential in transmission housing. The crown wheel is positioned on left-hand side (same side as cover for final drive).
- Install cover for final drive with 4 bolts (20 Nm).
- Turn transmission so that cover for final drive points upward.
- Turn differential 5 turns in both directions so that the tapered roller bearings settle.
- Place measuring plate VW385/17 on differential.
- Set up measuring tool using 30 mm extension.
- Set dial gauge (3 mm measuring range) - A - to "0" with 2mm preload.
Note:
^ Tip of dial gauge must be located at center of differential.
- Raise differential without turning, read clearance off dial gauge and write down.
^ Measurement in following example: 0.62 mm
Note:
^ Secure special tools VW521/4 and VW521/12 on right of differential (transmission side) to lift differential.
^ If the measurement has to be repeated, the differential must again first be turned 5 turns in each direction to settle the tapered roller bearings.
Determining thickness of shim "S1*"
Note:
^ Provisional shim "S1*" is replaced with final shim "S1" after determining backlash.
^ Total shim thickness "Stotal" remains unchanged.
Measuring backlash
^ Install pinion shaft with shims "S3" and "S4".
- Install differential with crown wheel: S1 is installed on cover side, S2 in transmission housing.
- Install cover for final drive and tighten bolts to 20 Nm.
- Insert crown wheel adjusting tool VW521/4 and VW521/12.
- Turn differential 5 turns in both directions so that the taper roller bearings seat properly.
- Secure universal dial gauge bracket VW 387 to housing.
- Install dial gauge with dial gauge extension VW382/10 (6mm flat).
- Adjust measuring lever VW388 to distance "a" = 79 mm (for diameter 188 mm crown wheel).
- Measure play between teeth faces (backlash) as follows:
- Turn crown wheel until it makes contact with the face of one tooth (end of backlash travel).
- Preload dial gauge to 2 mm and set to "0".
- Turn back crown wheel until it makes contact with opposite tooth face (backlash).
- Take backlash reading and note down measured value.
- Turn crown wheel through 90 degrees and repeat measurements a further 3 times.
Determining average backlash
- Add the four measured values together and divide by four.
^ Result: the average backlash is 1.16 mm: 4 = 0.29 mm
Note:
^ If the individual measurements differ from each other by more than 0.06 mm, the installation of the crown wheel or the final drive gear set itself is not correct. Check installation; replace final drive gear set if necessary.
Determining thickness of shim "S2"
- Determine shim(s) according to table.
Available shims for "S2"
Determining thickness of shim "S1"
- Determine shim(s) according to table.
Available shims for "S1"
Adjustment, checking
- After installing shims "S1" and "S2", turn differential 5turns in both directions so that the tapered roller bearings settle.
- Measure backlash four times on circumference.
^ Specification: 0.12 to0.28 mm
Note:
^ Adjustment must be repeated if backlash is outside tolerance. The total shim thickness "Stotal" must remain unchanged.
^ Deviation between individual measured values must not exceed 0.06 mm.