help! strange thudding noise from rear end when accelerating

[KVF]

Lol thanks guys, when I read csb for the first time I tried coming up with all these things that it could stand for but yea that totally makes sence now

But one thing, I never hear it while I'm going fast lik 60 on the highway or even slowly accelerating from that. Could it still be that?

Yes. Hard acceleration applies enough snap torque to cause the issue. If you are just cruising (regardless of the achieved speed) you are not applying enough load to force the issue. Unfortunately, the issue is hard to diagnose. If you have access to a lift, put it in the air and try to push the shaft side to side and up and down. Also take a look at you rear diff bushing and mounting bolts.

[Oolop]

Lol thanks guys, when I read csb for the first time I tried coming up with all these things that it could stand for but yea that totally makes sence now

But one thing, I never hear it while I'm going fast lik 60 on the highway or even slowly accelerating from that. Could it still be that?

[Vince30]

The csb is the center support bearing, it is in the middle of your driveshaft, mine is out right now, it sounds like your driveshaft is banging on the bottom of your car (because it is) lol.

[Dude]

Thanks guys for the quick response

Sorry, what exactly is the csb?

And I'll check for all that tomorrow, hopefully, and let u guys know what I find out, thanks!

Center support bearing. Its what holds the driveshaft up between the tranny and the diff.

[Oolop]

Thanks guys for the quick response

Sorry, what exactly is the csb?

And I'll check for all that tomorrow, hopefully, and let u guys know what I find out, thanks!

[Fidhle007]

Check your Subframe mounts too...

That may not be the source of your noise but I can still guarantee you that they're broken if you haven't changed them. If they are it replacing them should quiet things down a lot.

[jlevie]

A thuding noise that only occurs when turning will be a half shaft or the differential. But if the noise occurs under acceleration in a straight line the probability moves to the CSB and drive shaft.

[Oolop]

also when i start from a stop and make a left turn, like top of 1st gear or accelerating harder on 2nd. been happening since i got the car about 3 or 4 months ago (1987 325e 5-speed bone stock)

i checked my guibo's they're fine, checked my axles and one boot is torn but i think that just happened, 2 different shocks in the back...

speaking of the axles, i can somewhat pull them out of the diff, like an inch and a tad but not completely out. one was a bit out but i pushed it back in, drove, and same thing happened.

my co worker said it might be my diff

any suggestions? thanks very much