Hello all,
ohlord from mercedesforum.com sent me here. So here's my story:

Had a customer bring in a 1998 E320 4MATIC with a broken front drive shaft. When I say broken, I mean it was broken in half and the front half was gone.
We had a new shaft made and installed it. We went to test drive the car and noticed it wouldn't move and was making a noise. Then we noticed the right side axle was popped out of the front diff. We pushed it back in and checked to make sure it was locked into place. Test drove the car and everything seemed fine.
Car was picked up and towed back in about a week later with the axle popped out again. This time, we removed the axle and replace the retaining ring on the end, then reinstalled it. This time, it seemed to lock in a little tighter.
A couple of weeks go by and the customer comes in with appeared to be a broken idler pulley and says his serpentine belt is shreaded. Since we don't do engine work, I refered him to another shop who repaired the problem.
I come into work today and found the car in the parking lot. Again with the axle out. The customer came in said he could smell rubber burning at the same time the axle came out. The new serpentine belt does have some wear on the edge but I can't see how these two problems are related.
We have a All-Data program and I cannot find any info on the front diff. The mounts appear to be in good shape and can't find any excessive movement to cause the axle to come out.
I was hoping this issue would sound familiure to someone here and they could shed some light on the subject.
Sorry for the long post. I just felt like I should start from the beginning.
Thanks,
Jeff Bradley
Indianapolis, In