Terrytown

I have a rotary continuous thumping sound coming from the back of car. It's most pronounced when starting to drive from a stop or slightly more noticable when backing up and turning. When driving it sounds like I'm driving over the expansion joints on a concrete slab highway. Thump - thump - thump etc... ad nauseum. I checked the main drive shaft U-Joint and it seems perfect visually. I suspect pinion gear pin in the differential or CV Joints on the rear wheel drive shafts. Any thoughts of similar experences. Engine runs like a swiss watch and the transmission shifts beautifully.

chassis

Driveshaft center bearing or transmission mount or propshaft u-joint.

MJ50

moved to W204 forum...

cvx5832

My thoughts are also on the propshaft u-joint. Have you checked the flexdisk?

Terrytown

I suspected the prop shaft U-Joint and as painful as it is I may replace both. When I back up while turning left out of the garage it appears to be more distinctive. So left rear is more questionable. I will definate look at the flex disk and the center drive shaft mount bearing. Thank you all for your input.