I do have a clunk in the diff. To verify I jacked the car with both rear wheels off the ground and and rotated each wheel in each direction and could get about 1/4" of play before the yoke on the diff would turn. It also whines. Will try a heavier weight gear oil as loubapache suggested as a cheap interim. Compared to live axle rear drive cars the diff noise on a MB is much more noticeable, Maybe cause the diff is bolted directly to the car instead of through shocks and springs?
Didn't check the center bearing as i didn't know it had one
Still waiting for my cd-rom to arrive. Will check it this weekend.
I looked at the flex discs ealier. The front one looks like it's brand new. The rear one looks original. I am going to try and get the service records for it from the MB dealer today. That might answer a few questions. I've only had the car for about 2 weeks.
Thanx for all the suggestions, this forum is awesome!