2. Remove the differential cover (see section Removal and installation the differential housing).
3. Apply alignment marks with paint or scraper (indicated by arrows) on the flange, pinion shaft and pinion shaft nut to ensure proper assembly.
4. Remove the lock plate, then fix the input flange in place and loosen the flange nut.
5. Using a puller, remove the inlet flange.
If the pinion shaft has been grooved where it contacts the old seal, consult a qualified technician for further action. A new pinion shaft bushing may also be required.
6. Remove the old seal with a special tool or a large screwdriver. Make sure that you do not scratch the seal seat.
7. Dip the new seal into the differential fluid. Press it into place, with the jaws facing in, using a large socket or piece of pipe.
8. Lightly lubricate the input shaft and press the input flange onto it, but do not try to seat it all the way. Screw on the flange nut and use a torque wrench to slowly tighten it, noting the force at which the marks align - it should be close to that specified in Table of sizes and adjustment data. If the force required to align the marks is slightly less than required, the pinion shaft sleeve may need to be replaced. Since this work requires special tools and experience, it is best to leave it to a BMW dealer service department or auto repair shop.
9. If the required torque is reached before the marks are aligned, do not continue to tighten the nut until they are aligned.
Do not tighten the nut after aligning the marks and back, as this will result in pinching the gear shaft sleeve.
(This article is based on data from the website «www.bmwman.ru»)