Thumping sound in rear of 93 318i

[sOuNdDoCtOr]

I have recently noticed a thumping sound coming from the rear of my 93 318i. It happens at two different times. Sometimes I hear it when I downshift(a friend says this is normal), and sometimes I hear it when I'm making a right turn. The thump isn't very loud and only happens once. Any help is appreciated.

[Jared at Pelican Parts]

Some things to check,

- Shock mounts, It's possible that one or both upper shock mounts are worn out. Essentially, it is a small piece of rubber that suports the top of the shock in the rear, and it's pretty common for these to wear out, causing the occasional knocking sound.

- Driveshaft Flex disc, This too, is another piece of rubber that connects the driveshaft to the transmission. It is desgined to work as both a vibration damper and and a coupling. When they fail, it causes a knocking sound during acceleration.

- Differential carrier bearings, a long shot, but you mentioned it makes the noise during right hand turns. If the bearings in the diff are shot, it can whine or knock during turns.

[sOuNdDoCtOr]

Thanks for the info. All of it has led me to believe that it is probally a worn bushing. The sound only comes from the rear and never happens when I accelerate.