Disassembling the rear axle (BMW 3 Series E21)

Remove the rear axle and drain the oil from the crankcase.

Remove the differential output shafts (see above).

Place alignment marks on the differential bearing caps and remove the caps. Remove the adjusting rings.

Remove the rear cover and take the differential out of the axle housing.

Disassembling the differential

Apply relative position marks to the driven gear, pinion and differential case.

Remove the eight mounting bolts and remove the driven gear from the differential case.

Knock out the locking pin from the satellite axle and press out the axle.

Insert the differential output shaft and, turning it, remove the satellites from the differential box.

Remove the axle gears, support washers and adjusting washers from the differential box.

Differential assembly

Lubricate the thrust washers and adjusting washers with hypoid gear oil.

Install the axle gear without the support and adjusting washers, the satellites into the differential box and insert the satellite shaft.

To select the adjusting washer, install the device with the indicator as shown in the photo.



Move the axle gear sharply downwards and set the indicator arrow to zero.



Move the axle gear sharply upwards with a screwdriver and record the indicator readings. Subtract 0.05 mm from the resulting value to obtain the total thickness of the axle gear support and adjusting washers.

Repeat the above operations for the other axle gear.

Remove the satellite axle and satellites from the differential box.

Install the adjusting and support washers into the differential box, directing the latter with the convex side towards the axle gear.

Remove the indicator and, by screwing in the measuring device screw, which previously supported the indicator leg, move the axle gears apart so that the satellites can be installed in the differential box.

Insert the satellite axle and secure it with a cotter pin.

Knock the drive pinion out of the rear axle housing by hitting its end with a hammer through a lining. Press the bearings off the drive pinion.

Using pullers, press out the outer bearing rings of the drive pinion from the sockets of the axle housing and remove the adjusting ring "X" from the pinion.