Ring Gear, Adjusting
Ring gear, adjusting
(Adjusting differential)
Special tools and workshop equipment required
^ VW 385/17 End measuring plate
^ VW 387 Universal dial gauge holder
^ VW 388 Measuring lever
^ VW 521 Adjustment tool
^ 3177 Clamp
^ V.A.G 1331 Torque wrench
Special tools and workshop equipment required
^ VW 382/10 Dial gauge extension
^ VW 402 Thrust plate
^ VW 408 A Pressure tool
^ VW 459/2 Installing and removing tool
^ VW 472/1 Thrust piece
^ VW 681 Extractor lever
Special tools and workshop equipment required
^ 2050 Thrust plate
Determining total shim thickness "Stotal" for shims "S1" + "S2"
(adjusting pre-load of tapered roller bearing for differential)
^ Drive pinion removed
- Pull out flange shaft oil seal with oil seal extractor VW 681.
- Remove tapered roller bearing outer race for differential and remove shims.
- Drive outer race for small tapered roller bearing with shim "S2" into transmission housing. For measurement purposes use a 1.20 mm thick "S2" shim (2 shims of 0.60 mm).
Note: For measurement purposes a shim "S2" with a thickness of 1.20 mm is initially inserted. It is referred to as "S2" in the following. After determining the backlash "S2*" will be replaced by the correct "S2".
- Press outer race for tapered roller bearing without shim "S1" into cover for differential.
- Insert differential without drive wheel for speedometer sensor -G22into transmission housing.
- Install cover for differential with 4 bolts (25 Nm).
- Position transmission so that cover for differential faces up.
- Turn differential 5 turns in both directions to settle the tapered roller bearing.
- Place measuring plate VW 385/17 onto differential.
- Assemble measuring equipment, use a 30 mm dial gauge extension.
- Set dial gauge (3 mm measuring range) to zero with 2 mm pre-load.
Note: The tip of the dial gauge must be positioned on center of differential.
- Lift differential without turning; read play on dial gauge and note.
^ Measurement in following example: 0.62 mm
Note: If measurement has to be repeated, differential must again be turned 5 turns in each direction to settle the tapered roller bearing.
Formula: =
"Stotal" "S2" + measurement + bearing pre-load
Example:
Inserted shim(s) "S2" 1.20 mm
+ Measurement 0.62 mm
+ Bearing pre-load (constant) 0.30 mm
= Total shim thickness "Stotal" for "S1" + "S2" 2.12 mm
Determining thickness of shim "S1"
Note:
^ The preliminary adjustment shim "S1" will be replaced with the final shim "S1" after determining the backlash.
^ The total shim thickness "Stotal" remains the same.
Formula:
"S1" = "Stotal"-"S2"
Example:
Total shim thickness "Stotal" for "S1" + "S2" 2.12 mm
- Inserted shim(s) "S2" 1.20 mm
=Thickness of shim "S1" 0.92 mm
Shims allocated from Parts Catalog.
Measuring backlash
^ Drive pinion and shims "S3*" and "S4*" installed
- Installing differential with ring gear: S1* is installed on cover side, S2* in transmission housing.
- Install final drive cover and tighten bolts to 25 Nm.
- Turn differential 5 turns in both directions so that the tapered roller bearings settle.
- Secure dial gauge holder VW 387 on housing.
- Install dial gauge with dial gauge extension VW 382/10 (6 mm flat).
- Set measuring lever VW 388 to dimension a:
- Measure play between teeth flanks (backlash) as follows:
- Turn ring gear until it makes contact with a tooth flank (end of backlash travel).
- Set dial gauge to 0 with 2 mm pre-load.
- Turn ring gear back until lying against an opposite tooth flank (backlash).
- Read backlash and note value.
- Turn ring gear 90° and repeat measurements another 3 times.
Note:
^ If drive pinion rotates when the differential is turned, install bracket VW 3177 -Also that backlash can be measured exactly.
^ Loosen the clamp in order to turn the ring gear.
^ Cut-out for large differential bevel gears must point toward drive pinion when differential is inserted.
- With holder 3177 inserted, install differential offset by 180° and repeat measurement.
Determining average backlash
- Add four measured values together and divide by four.
Example:
1st measured value 0.28 mm
+ 2nd Measured value 0.30 mm
+ 3rd Measured value 0.30 mm
+ 4th Measured value 0.28 mm
= Sum of measured values 1.16 mm
^ Result: The average backlash is 1.16 mm divided by 4 = 0.29 mm
Note: If the individual measurements differ by more than 0. 06 mm this means that the installation of the ring gear is not correct or that the final drive set itself is defective. Check installation, replace final drive set if necessary.
Determining thickness of shim "S2"
Formula: =
"S2" "S2" - backlash + lift
Example:
Inserted 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) as accurately as possible from table. Part numbers
The following shims are available for "S2"
Determining thickness of shim "S1"
Formula: =
"S1" "Stotal" - "S2"
Example: Total shim thickness "Stotal" for "S1" + "S2" mm 2.12 mm
- Thickness of shim "S2" 1.06 mm
=Thickness of shim "S1" 1.06 mm
Determine shim(s) as accurately as possible from table. Part numbers
The following shims are available for "S1"
Performing check measurement
- After installing shims "S1" and "S2", turn differential 5 turns in both directions so that tapered roller bearings settle.
- Measure backlash four times on circumference.
^ Specification: 0.12... 0.22 mm
^ Note:
^ If the backlash is beyond the tolerance, the adjustments must be repeated. The total shim thickness "Stotal" must not be changed when the adjustment is repeated.
^ The individual measurements must not differ by more than 0.06 mm from each other.