Originally Posted by Henn28

Those look like the dust covers on the output shafts. E53 with the 188 “medium” diff, correct? I did a full rebuild except for the pinion shaft, which I didn’t pull because that bearing was in good shape, and the preload was decent. There is a dust cover on the pinion shaft, but only one I believe. The output shafts each have a cover on them that should have remained on them, unless the shaft was/were damaged. No sense taking them off unless the shaft splines or race were damaged, which would be unlikely I think. It looks like he bent one up as well, so you’ll definitely need new parts.

Fortunately FCP shows them as available still, for $51ish. Unfortunately it’s an OE part and comes from Germany…4 to 6 weeks. You may want to try getbmwparts.com as they can get OE stuff much sooner, and expedite from Germany if you need it soonest. They also tend to have good prices on OE stuff, but more recently I’ve had to follow up on orders that they neglected to process.

RealOEM shows it as “dust guard ring”, part number 33131428097. You can see them on the below pic.