Ring Gear, Adjusting
Ring Gear, Adjusting
(Adjusting differential)
Special tools, testers and auxiliary items required
• Drift (VW 295)
• Dial gauge extension (VW 382/10)
• Magnetic plate (VW 385/17)
• Dial gauge holder (VW 387)
• Measuring lever, adjustable (VW 388)
• Pressure plate (VW 402)
• Punch (VW 408 A)
• Ring gear adjustment device (VW 521)
• Sleeve (30 - 14)
• Thrust piece (2050)
• Torque wrench (VAG 1331)
• Dial gauge
• Dial gauge extension 30 mm
A new ring gear adjustment is required when the following components have been replaced:
Transmission housing, final drive cover, differential tapered roller bearings, differential housing or the gear set
Adjustment overview, refer to => [ Adjustment Overview ] Adjustment Overview.
Determine total shim thickness "Stotal" for adjustment shims "S1" + "S2"
(Setting preload of taper roller bearing for differential)
• Drive pinion removed.
• If only the tapered roller bearing for differential has been replaced, ring gear can be removed from differential housing. Drive pinion then does not need to be removed.
- Remove flange shaft sealing rings.
- Remove outer races/tapered roller bearings for differential and remove adjustment shims, refer to => [ Differential ] Front Final Drive, Differential (0A3A Transmission).
- Drive outer race for right tapered roller bearing together with shim "S2" into differential housing. Use a shim " S2*" with a 1.30 mm thickness for measurement purposes (2 shims with 0.65 mm).
• For the initial measurement, an adjustment shim "S2" with a thickness of 1.30 mm is inserted. It is designated as "S2* " in the following. After determining backlash, "S2* " is replaced by final "S2".
- Pressing outer race for tapered roller bearing without shim " S1" into final drive cover.
- Insert differential into transmission housing. Ring gear is located on left side in front of final drive cover.
• O-ring is inserted in final drive cover.
- Install transmission cover with 4 screws (24 Nm).
- Turn transmission so that final drive cover faces upward.
- Turn differential 5 turns in both directions so that the taper roller bearings settle.
- Place magnetic plate (VW 385/17) on differential.
- Assemble measuring tool, use 30 mm dial gauge extension.
- Set gauge (3 mm measuring range) - A - to " 0" with 2 mm pre-load.
• Tip of dial indicator must be positioned on the center of the differential.
- Lift differential without turning it, read backlash on dial indicator and note.
• Measured value in following example: 0.62 mm
• To raise differential, secure special tools (VW 521/4 ) and (VW 521/8) at right on differential (housing side).
• If measurement is repeated, differential must first be rotated 5 complete revolutions in both directions again to seat tapered roller bearing.
Formula: "Stotal" = "S2* " + measured value + bearing preload
Determining thickness of adjustment shim "S 1*"
• Initial shim "S1*" is replaced with final shim "S1" after backlash has been determined.
• The total shim thickness "Stotal" remains unchanged.
Formula: "S1*" = "Stotal" - " S2*"
Torsional backlash, measuring
• Drive shaft installed with shims "S3" and " S4".
• O-ring is inserted in final drive cover.
- Install differential with ring gear: "S1" is on cover side, "S2" is installed in transmission housing.
- Install transmission cover and tighten bolts to 24 Nm.
- Insert locking sleeve (VW 521/4) and (VW 521/8).
- Turn differential 5 turns in both directions so that the taper roller bearings settle.
- Secure dial gauge holder (VW 387) to transmission housing.
- Insert dial gauge with extension pin (VW 382/10 ) (6 mm).
- Set measuring lever (VW 388) to dimension "a" = 75 mm (for ring gear dia. 186 mm).
- Determine play between teeth flanks 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 off backlash and note measured value.
- Turn ring through 90° and repeat measurements 3 times.
• If drive pinion - 1 - turns when measuring, counter hold drive pinion so that an exact torsional backlash can be measured.
Determining average backlash
- Add four measured values together and divide total by 4 to determine average.
• Result: Average backlash is 1.16: 4 = 0.29 mm
• If measurements vary more than 0.06 mm from each other, ring gear or gear set is not installed correctly. Check installation, replace final drive set if necessary.
Determining thickness of adjustment shim "S 2"
Formula: "S2" = "S2* " - measured torsional backlash + specified torsional backlash
- Determine shim(s) according to table.
Available adjustment shims for "S2"
* Using shim tolerances it is possible to find the exact shim thickness required, insert two shims if necessary.
Determining thickness of adjustment shim "S 1"
Formula: "S1" = "Stotal" - " S2"
- Determine shim(s) according to table. Part numbers.
Available adjustment shims for "S1"
* Using shim tolerances it is possible to find the exact shim thickness required, insert two shims if necessary.
Measurement check
- After installing adjustment shims "S1" and " S2", rotate differential 5 rotations in both directions so that tapered roller bearings settle.
- Measure backlash four times on circumference.
• Specified value: 0.12 to 0.22 mm
• If drive pinion - 1 - turns when measuring, counter hold drive pinion so that an exact torsional backlash can be measured.
• If backlash is outside tolerance, repeat adjustments. Do not change total shim thickness "Stotal" while doing so.
• The individual measurement values can deviate a maximum of 0.06 mm from each other.