Adjusting circumferential backlash Note

The backlash to be set is embossed on the ring gear.

1. Mount gear set using the shims "S3" determined while adjusting the drive pinion and tighten all mounting screws to 50 Nm


Make sure the collar nut of the drive pinion is tightened to 250 Nm (184 ftlb).

2. Fit the adjusting shims (Si + S2) determined into the transmission case and the transmission side cover, respectively.

3. Fit differential and transmission side cover and tighten all hexagon head bolts of the cover to 23 Nm (17 ftlb).


Always make sure that there is a certain amount of backlash when tightening the hex bolts. Never allow the drive pinion to bind.

4. Assemble measuring lever VW 388 and adjusting device VW 521/4 and adjust lever length to 80 mm with the plunger. Refer to dimension "a" in the picture.

5. Insert adjusting device with clamping sleeve (Special Tool 9145) into the differential and clamp firmly.

6. Rotate differential in both directions several times to settle the tapered roller bearings.

7. Fit universal dial gauge holder with flat extension in such a way as to produce a right angle between dial gauge axis and lever.


Dimension "a" = approx. 80 mm

8. Turn ring gear carefully at the clamping screw of the adjusting device up to the stop and set the dial gauge to zero. Turn back ring gear and read off circumferential backlash. Note the reading.


When carrying out measurements, the drive pinion must be blocked with Special Tool


9. After turning the ring gear a further 90° each, repeat measuring procedures three times. The measured values must not deviate from one another by more than 0.05 mm.


The backlash to be adjusted is embossed on the ring gear. The actual value may be less than the specified value by - 0.05 mm. Under no circumstances must the backlash be greater than the specified value.

10. If the required backlash cannot be obtained, replace spacers (S1 + S2) again. The total shim thickness (S tot.) must not be altered, however.


Changing the shim thickness of "S1" or "S2" by 0.05 mm shim results in a change of backlash by approx. 0.1 mm.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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