Rear End Knock, Not Diff Bushes

[Roley94]

Recently had my diff bushes replaced with nolathane, now there is a knocking noise that occurs when turning left or right, over big bumps and when reversing after driving forwards. Also at low speeds when taking my foot off the accelerator and back on again will cause it to knock.

Car is a 2005 BF turbo sedan.

Sounds like some other bush may be worn but not sure what.

[senna_T]

Sounds like your diff centre is getting loose and creating some free play or back lash. The nolathane bushes will be transferring noise through to the cabin more than the rubber ones were

[Force88]

mine did this exact same thing (not when turning though) after replacing the center diff bush to a nolethane one but I never figured out what it was. its a pretty awful sound. any possible fix?

[Roley94]

Also noticed loud diff whine at exactly 60kmh and over 100kmh that wasnt there before

[DD-XR-6T]

The whine is your diff. The clunk is the play in it. Basically the rubber bushes were making it less noticeable. Sorry to tell ya mate but your diff has had it.

[senna_T]

Check the installation of the bushes too. A polyurethane bushing will not create a noise unless it is installed incorrectly, it will only transfer a noise or vibration that was already there but hidden by a soft, voided rubber bush.

[Kroozin]

Sounds dumb but r u sure your exhaust isn't tapping against something?

Easy check is to put your foot on the exhaust tip and shake it around abit.

I know that doesn't fix your whine though

[Roley94]

It doesn't sound like an exhaust knock and it is felt through the car as a thud

[Roley94]

Can these diffs be shimmed if it does have to much backlash

[DD-XR-6T]

If the thump is mainly when it's a rough gear change, on off and on the throttle rapidly or hard takeoffs the diff bush was put in wrong/broken again or the diff has some mad backlash goin on. The whine pretty much gives away what it is though.