Ring Gear, Adjusting

Ring gear, adjusting, 01A, 5 SPD. M/T (AWD)
(Adjusting differential)

Special tools, testers and auxiliary items required:

^ Magnetic plate 50 mm dia. VW 385/17
^ Dial gauge holder VW 387
^ Measuring lever VW 388
^ Ring gear adjustment device VW 521
^ Torque wrench V.A.G. 1331
^ Torque gauge 0 to 600 Ncm

Procedures after which ring gear must be adjusted.

Note:
^ Tapered roller bearings for differential are low-friction bearings. Therefore friction torque can only be used for checking measurement in a limited way. A correct adjustment is only possible by determining the total thickness "S total".
^ Do not grease new tapered roller bearings for friction torque measurement. The bearings are already greased with a special oil from the factory.

Determine total shim thickness "S total" for adjustment shims "S1" + "S2"
(adjust preload of tapered roller bearing for differential)
^ Pinion shaft removed or ring gear detached from differential housing
^ Pry out drive flange seal using tire iron.
^ Remove tapered roller bearings for differential and remove adjustment shims.
^ Press tapered roller bearing outer race for left side of differential housing (housing side) together with shim "S2" into differential housing. Use a shim "S2*" with a 1.00 mm thickness for measurement purposes (1 shim with 0.80 and 1 with 0.20 mm).

Note:
^ For the initial measurement, an adjustment shim "S2" with a thickness of 1.00 mm is inserted. It is designated as "S2*" in the following. After determining backlash, "S2*" is replaced by final "S2".

^ Press in tapered roller bearing outer race for right side (cover side) of differential without shims up to stop.
^ Insert differential in housing. Ring gear is on right side (cover side).
^ Install cover and tighten bolts to 25 Nm.





^ Install Locking Sleeve VW521/4 and bushing 26/30 mm VW521/8 on housing side of differential housing.
^ Rotate cover side of differential housing upward.
^ Turn differential 5 rotations in each direction to seat tapered roller bearing.
^ Place Magnetic Plate 50 mm Dia. VW385/17 on differential.





^ Install measuring tools.

A - Dial gauge extension approximately 30 mm long

B - Hex bolt M8x45

^ Place dial gauge extension on center of magnetic plate VW 385/17.
^ Set gauge (3 mm measuring range) to "0" with 2 mm preload.





^ Lift differential without turning it, read backlash on dial indicator and note.
^ Measured value in the following example: 0.50 mm

Note:
^ If measurement is repeated, differential must first be rotated 5 complete revolutions in both directions again to seat tapered roller beating.

Formula: "S total" = "S2*" + measured value + bearing preload





Determining shim thickness "S1"

Note:
^ Initial shim "S1*" is replaced with final shim "S1" after backlash has been determined.
^ The total shim thickness "S total" remains unchanged.

Formula: "S1*" = "S total" - "S2*"





Determine shim(s) according to table.

Measuring friction torque (check measurement)
^ Drive pinion removed
^ Differential with shims "S1*" and "S2*" installed





^ Position torque gauge 0 to 600 Ncm - A - on differential.
^ Read friction torque.

Friction torque specified values:





Note:
^ Tapered roller bearings for differential are low-friction bearings. Therefore friction torque can only be used for checking measurement in a limited way. A correct adjustment is only possible by determining the total thickness "S total".
^ Do not grease new tapered roller bearings for friction torque measurement. The bearings are already greased with a special oil from the factory.
^ For a new adjustment of the gear set, the pinion shaft adjustment should now be checked.

Adjusting backlash
(position of ring gear in transmission housing)
^ Pinion shaft with shim "S3" installed
^ Differential with shims "S1*" + "S2*" installed
^ Insert differential in final drive housing, install cover and tighten all bolts to 25 Nm.
^ Turn differential 5 rotations in each direction to seat tapered roller bearing.





^ Install measuring tools.
^ Use dial gauge extension VW 382/10 (6 mm flat).
^ Set measuring lever VW 388 to dimension "a" = 60 mm.
^ Determine backlash between teeth flanks as follows:
^ Turn ring gear until it contacts a tooth flank (end of backlash travel).
^ Set dial gauge to "0" with 1 mm preload.
^ Turn ring gear back until it contacts opposite tooth flank (backlash).
^ Read off backlash and note measured value.
^ Turn ring gear 90° every time and repeat measurement 3 times.

Note: If measurements vary more than 0.06 mm from each other, ring gear or gear set is not installed correctly. Check installation, replace gear set if necessary.

Determining average backlash





Result: The average backlash is 1.16 mm / 4 - 0.29 mm

Determining adjustment shim "S2" thickness

Formula: "S2" = "S2*" - backlash + lift





Determine shim(s) according to table.

Available shims for "S2"





Using shim tolerances, it is possible to find the exact shim thickness required, insert two shims if necessary

Determining adjustment shim "S1" thickness

Formula: "S1" = "S total" - "S2"





Determine shim(s) according to table.

Available shims for "S1"





*Using shim tolerances, it is possible to find the exact shim thickness required, insert two shims if necessary

Checking measurement





^ Pinion shaft with shim "S3" installed
^ Differential with shims "S1" + "S2" installed
^ Turn differential 5 rotations in each direction to seat the tapered roller bearing.
^ Measure backlash 4 times on circumference.
^ Specified value: 0.12 to 0.22 mm

Note:
^ If backlash is outside tolerance, repeat adjustments. Do not change total shim thickness "S total" while doing so.
^ The individual measurement values can deviate a maximum of 0.06 mm from each other