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[jaybrgsn]

I just had the clutch replaced on my 87 325is. Now there's this loud clunk clunk clunk and vibration coming from the rear center that only occurs at 15-22 mph, then goes away as the car speeds up. It doesn't happen too much if I'm really gentle giving it gas in that speed range. My guess is bad flexdisk or universal joint. Does anyone have any ideas on what it might be?

[AussieE30]

Sounds like the nuts didn't get tightend. But otherwise you're on the right track. is the clunk there when you transit from leading to trailing throttle? if so, it's something loose.

[Chas]

the axle must be aligned properly or it will do that It is imperative! Chas

[Ken Juul]

The flex disk is a large rubber donut shaped piece that attaches the drive shaft to the transmission output flange. Takes the place of a front u-joint. If it is installed backwards, it will only last a couple hundred miles before it self destructs. If it should let go, the foward end of the driveshaft can do a lot of damage. When installed properly, the arrows at each bolt hole show the direction the bolt should be installed. Have it checked right away. Another possibility is the center driveshaft bearing. When installing it, it should be preloaded a short distance toward the front of the car. Don't have my manual with me, can't remember how much.

[jaybrgsn]

Thanks for all your input. The flexdisc was in bad shape. It was a pretty simple repair and inexpensive, once you take off all the stuff to get to the flexdisc. It's driving perfectly smooth again.