thump after accelerating

[yack447]

hey guys i was wondering if anyone knew why i hear a thump when i let off the gas after acceleration. i drive a 90 525i that is an auto. i hear a thump when i let off the gas after accelerating hard. if anyone could help that would be greatly appreciated

[Atticka]

I remember a similare problem with the E36's and transmissions getting worn...try a search, something should come up.

[abakos]

I remember a post about E28s that you could get a "clunk" after hard acceleration. The suspect was rear bushings, I can't remember which ones, but I'm thinking subframe.

It would probably be worth your while to inspect all your mounts and bushings.

Regarding the tranny...I dunno. Anything's possible.

Does it still do it in reverse?

[yack447]

yeah it clunks in reverse too

[abakos]

Universals?

[yack447]

sorry for my ineptitude but what are you refering to by universals??

[abakos]

Sorry-- Universal joints on the drive shaft. They have needle/roller bearings in them. When they go bad they'll "clunk".

The way to test these is just to crawl under the car and try to twist the driveshaft by hand. There should be ZERO play in it.

There are two universals. One on either end of the driveshaft. I don't think I've heard of one going bad in a bimmer, but I'm still fairly new to the bimmer scene :) I know especially in pickups, you have the solid rear axle, so the geometry changes are huge and is rough on the universals. BMWs with the independent rear has the pumpkin in a spot that doesn't travel with the suspesion (mounted to the subframe, which is bolted to the body). There is still some movement, but not a whole lot, so they shouldn't wear as fast.

I'm picking my brain trying to think of everything that would "clunk" when you let off the throttle...

[yack447]

thanks alot for the help i will check it out

[SoonerE39]

Ran over a body?

[yack447]

nah, no people although i would like to hit a few