Originally Posted by ROGER E.

Those metal discs are mass dampers, added about that time to quiet down the gear whine in the differential. My '89 190E 2.6's ring & pinion sang like a birdie when the car was new and after two diff replacements the MBUSA rep said "We have a redesign coming soon if you can wait and we will install one in your car when it's available." Almost two years later a new diff assembly arrived with the mass dampers and the noise was gone. This noise was in the six cylinder 190E, not the four cylinder. I had one of those dogs also, much to my regret.