I recently ended my 17 year BMW ownership run and bought my first Mercedes last month. It's a 1993 500SEL with 89k. It needed some new rear rotors and I noticed a rear thumping sound on bumps mostly on the passanger side. The next thing I tackled, based on all the threads here was the rear spheres. Needless to say, 2 new spheres and 240 dollars later I still have the thump. (by the way only one thread mentioned lowering the exhaust to get the removed and new sphere in and out on the drivers side, anyone reading this as it relates to spheres be prepared to do so). Anyway, My next guess and approach would be to battle either the shock bushings, coil bushings, frame bushings or is there a rear differential bushings? I hate to just start stabbing at "my" ideas of what it might be. Any advice on diganosing any of those next steps to lead me the right direction? I get the thump on potholes and manhole covers etc. in the road. It seems to be concentrated mostly on the passanger rear side but I am still listening to be sure.
Thanks,
Steve

1993 500sel