Adjust gear backlash at differential assembly

AR35.30-I-0475A

Adjust gear backlash at differential assembly

24.4.07



Removal

1

Remove differential assembly.

Rear axle 746.642/645/646/647/669/

680/681/682, 748.800 in model 684

AR35.30-I-0432A

2

Remove cotter pin (5) on left bearing cap (7)

3

Remove locking plate on right bearing cap

4

Loosen bolts (6) on left bearing cap (7) and bolts on the right bearing cap and then screw in again until they abut

 The bolts must not exert any contact force acting against the two bearing caps.

5

Loosen left threaded ring (9) and right threaded ring

 The preload of the tapered roller bearings is reduced by loosening the threaded rings. The threaded rings must just still abut the tapered roller bearings.

6

Install dial indicator holder with the dial indicator on the rear axle housing and attach dial indicator tip on the back of the ring gear under 2 mm preload



*001589532100



*363589022100



Checking

7

Check bearing of differential housing with ring gear (8) for axial play

 Attach the two assembly levers carefully so that the differential housing with ring gear and rear axle gear housing are not damaged.

 The bearing may not show any axial play. If axial play is established:


Eliminate axial play by screwing in the left threaded ring (9).

8

Screw in left threaded ring (9) and right threaded ring by one tooth respectively

 The tapered roller bearings receive the necessary preload by screwing in the threaded rings.



*684589000700

9

Mount the dial indicator holder with the dial indicator on the rear axle gear housing so that the probe of the dial indicator is seated on a ring gear tooth under a preload of 2 mm

10

Check gear backlash

 Block the drive pinion and, for checking, move the ring gear by hand in both directions until a resistance is noticeable. In the process read off the value of the gear backlash on the dial indicator. Repeat check on two other teeth in each case offset by 120°.

*BE35.30-N-1001-04B

If specified value is not reached:


Adjust gear backlash.

AR35.30-I-0475-03A



*684589000700

 After the adjustment check the gear backlash again and repeat the adjustment if necessary.

11

Detach dial indicator holder with dial indicator

12

Check contact pattern of ring gear and drive pinion

AR35.30-I-0475-02A

*BR00.45-Z-1002-07A

 If the contact pattern indicates a too large or too small installed dimension of the drive pinion, then the pinion housing with drive pinion must be removed and the installed dimension adjusted by adding or removing corresponding shims: 

Rear axle 746.642/645/646/647/669/
680/682, 748.800

AR35.30-I-0469A

Rear axle 746.681

AR35.30-I-0469B

 If the contact pattern indicates a too small or too large gear backlash: 

Adjust gear backlash.

AR35.30-I-0475-03A



*684589000700



Install

13

Tighten bolts (6) on the left bearing cap (7) and bolts on the right bearing cap



*BA35.30-N-1002-03G

14

Install cotter pin (5) on left bearing cap (7)

15

Install locking plate on right bearing cap

16

Install differential assembly

AR35.30-I-0432A

Number

Designation

Rear axle 746.642/645/646/647/669/680/
681/682,
748.800

BE35.30-N-1001-04B

Gear backlash between drive pinion and ring gear

New

mm

0,30

worn

mm

0,20 to 0,46

Number

Designation

Rear axle 746.642/645/646/647/669/680/
681/682,
748.800

BA35.30-N-1002-03G

Bolt, bearing cap of differential housing to differential assembly

Nm

240

Number

Designation

Order number

BR00.45-Z-1002-07A

Prussian Blue

-