1985 500SEL 120k mi. - Purchased vehicle Nov 2005 (my 2nd 126 sedan after owning '84 380SE for 10 years). Both cars serviced by excellent independent M-Bz shop. This issue has them (and me!) stumped. 500SEL previously owned by elderly lady who stored vehicle winters and had same shop do all service work during her 11 year ownership. Vibration in rear end, especially noticable above 50mph; feels and sounds like more right rear than left rear. More noise/vibration under load, accelerating; less when not under load or coasting.

My initial view - it felt like a cupped rear tire. Replace worn tires with no effect. Next replaced right rear alloy wheel, slight improvement. Next loaded rear end while on hoist - could see eccentricity, especially on right rear. Inspected ring and spider gears in diff - no unusual wear seen. Replaced rear axles; both were definitely not straight. The shop's opinion was that perhaps the storage each winter had caused a slight corrosion to develop on the axle shafts and resulted in uneven wear. Replacing axles improved vibration somewhat; still hear noise above 50mph but it is lessened. Vibration still being felt in seat of pants, but not until about 65mph under load and not as severe as previous. Alignment check ok, no signs that the car has been in any kind of accident.

My currnent thoughts - wheel bearing, slightly bent wheel hub, mis-aligned ring/spider gears in diff. Note - this year/model has anti-squat feature on rear end but does not have self-leveling pneumatic suspension.

Any ideas, suggestions, etc? Anyone run into this before?