Extension Housing: Service and Repair

Exploded View, Transmission Rear Cover And Rear Sealing Ring:

Special Tools:

Shop Made Tool:

NOTE: The press-in alignment tool must be manufactured to the specified dimensions.

NOTE: In vehicles with 4MATIC an adapter housing and internally-geared wheel are fitted in place of the rear transmission cover and three-arm flange. After removing the transfer case, proceed with item 11.

Removing and Installing





1 Jack up vehicle at rear.
2 Unscrew drain plug (1) from transmission and drain off oil.

Installation Note
Tightening torque for drain plug 14 Nm.

3 Check oil level and correct.
4 Detach exhaust system at the plug connection (arrows) and remove with shielding plate.





5 Remove cross member (22) with rear engine mount.
6 Slacken retaining strap (21).
7 Unscrew exhaust support (34).





8 Unscrew cable (20) on kickdown solenoid valve (61). Unscrew bolt at pulse generator (24) and pull out pulse generator.

NOTE: In vehicles with mechanical speedometer, seal off shaft.

9 Unscrew flexible disk (25) on joint flange, slacken propeller shalt clamping nut and compress propeller shaft as much as possible.

Installation Note
Tighten propeller shaft clamping nut securely to 30 - 40 Nm.





10 select parking lock.
11 Unscrew twelve point collared nut (62) and pull off propeller flange (64) or internal gear (64a).

Installation Note
Tightening torque 120 Nm, then knock collar into depression on drive shaft (arrow) using a suitable drill.





12 Remove washer (65).
13 Unscrew combined bolts and washers (71) and pull off rear cover (70) or adapter housing.

CAUTION:
When removing the rear cover (70) or adapter housing. ensure that the kickdown solenoid valve is not damaged. If necessary, slacken the kickdown solenoid valve and rotate a little.

Installation Note
Check gasket for damage. Generally, it may be used several times but must not be coated with sealing compound. Screw in combined bolts with washers (71) and tighten to 13 Nm (8.8) or 28 Nm (10.9).

NOTE: Degrease bolts and coat with non-hardening sealing compound.





Dismantling and Assembling

14 Press out radial sealing ring (66) using a screwdriver.

Installation Note
Knock in using a suitable drift.





15 Take out circlip (68) and knock out single-row deep-groove ball bearing (67).

Installation Note
There must be no clearance between the circlip (68) and the single-row deep-groove ball bearing (67). For this reason. circlips are available in 3 different thicknesses (2.0 - 2.1 - 2.2 mm).

When inserting the circlip ensure that it is correctly seated in the groove. If the circlip cannot be inserted, a thinner circlip must be used. If there is play between the circlip and the single-row deep-groove ball bearing, a thicker circlip must be inserted.





Use a feeler gauge (0.10 mm) to check whether there is clearance.





16 Remove drive gear (129) for mechanical speedometer. Remove circlip (131) and take out shaft (130) and drive gear (129).





17 Pull radial seal ring (132) out of rear cover (70).

NOTE: In order to facilitate removal, a hexagon bolt M12 can be screwed into the radial seal ring and clamped in a vise. The radial seal ring is removed by gently tapping the transmission cover with a plastic mallet.





Installation Note
Press in radial seal ring (132) carefully up to the stop using the shop-made alignment tool.





18 A new plastic bushing (69) with O-ring (arrow) must be installed in vehicles with electronic speedometer. Insert the plastic bushing using the shop-made press-in alignment tool.