Thank you so much for the info. I am new to Mercedes, and just starting to work on the car. I have always owned Porsches. I am going to go ahead and buy the differential and install it. Does any one know for sure how to isolate the problem to the differential. It does not sound like a wheel bearing to me, as it does not change pitch or loudness when turning hard corners. The flex plate is new. I guess it could be the drive shaft bearing. The low whurring sound lasts almost untill the car rolls to a stop. Any help to confirm my diagnosis would be great from the members. I am going to go ahead and purchase the other differential too, if you guys think I would be able to sell it on this forum. If I purchase the other sought after one for four hundred do you guys think I would be able to sell it for more. It is new, and in the box. There is also another one of these that looks new, but has had the cover removed. It looks unused inside, as there is absolutely no wear marks on the ring or pinion. It looks like someone removed the axle stub shafts, as they can be pulled out. Is there supposed to be retaining rings that secure the stub shafts?? I see a machined ring on the end of these. Any help at all would be appreciated on these.

Thanks again,

Rod