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Differential Output Shaft Seals

Warning: If you are not competent or do not feel comfortable doing any of these modifications or procedures, then please do not do so. I will not be held responsible for any damages caused by a result of your actions. Now on to the fun stuff!

These were replaced because the driver's side was seeping a little oil. I figured I might as well do them both while I had it out. Now would also be a good time to replace the differential fluid. I run Redline 75w-90 in mine.

2 Ouput shaft sealing with locking ring (BMW Part # 33 10 7 505 602)
[I'm not 100% sure this is the part number, check with your local $tealer to be sure! Other cars may be different!]

Wrenches and Sockets (this will require the use of a torx bits to get the half shafts off the diff case, and possibly a 14mm hex socket for the drain and fill plugs)
Jack stands
Punch, chisel, hammer, or seal puller
Pry bar

1.) Chock the front wheels, jack the car up, and support it with jack stands

2.) Remove the torx bolts from the halfshafts at the CV joint and tie them up and out of the way. It's not good to let them half under their own weight, it may damage the CV.

3.) I chose to just remove the whole differential at the time because I'm crazy or something. I really don't know. You should be able to do this with the differential still in the car. In that case you should be able to pop the output shafts out now. I had to pull the driveshaft and differential bolts next and pull the whole deal out of there. I drained the differential fluid before removing it, but I'm not sure if it's necessary while it's still in the car. Somebody give it a try and let me know. (sorry if you make a mess!)

4.) Use a pry bar or equivalent to gently release the lock ring inside the diff on the ouput shaft. Just pry upwards on the ouput flange. It really shouldn't take much.

5.) Now you have exposed the seal, so take note of its depth and then pry it out with the seal puller or a chisel as I did. Be careful not to gouge the inner surface as it may lead to a leak! The picture shows the seal removed, with the locking ring exposed.

6.) Remove the locking ring from the slot. I used a screwdriver to pull one edge up and then pop it out. Watch your eyes!

7.) Now you can slip the new locking ring into the slot. It's a little tricky, but it goes in about like it came out.

8.) Coat the new seal with some oil and gently drive it into place to the same depth as the one removed.

9.) Slide the output shaft back in. It may need rotated a little to align it with the internal splines. It is fully seated when the locking ring clicks into place. It just clicked right in place for me.

10.) If you left the differential in the car, then just reattach the half shafts and you should be good to go. Be sure to refill the differential if you drained it.

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