I recently did a diff & transmission oil change, and straight after that I took the car for a test drive. Straight away I noticed a knocking/clunking sound comming from the rear centre of the car when going over speed bumps or any rough road surface. This happens regardless of the speed when going over bumps and is really irritating. I never used to get this problem before and the car drives like a dream, apart from this 1 issue now.

Is there anything in particular I should check?

 

Rear center? Do you have anything in the trunk?

I believe there is a TSB out there that covers sheared endlinks, and the symptom is loud thumps when driving over bumps.

 

Yeah there's some stuff in the trunk. Tennis rackets, pool cue, kitchen paper and a box of biscuits. These have been in there before the problem started occuring though. I'll check rear endlinks tomorrow its a bit dark at the moment. I also had an accident which was repaired 3 weeks ago. It's been perfect since then. only after this oil change I start experiencing problems!

 

By the way it has REDLINE Synthetic Gear Oil 75W-90 GL5 in the Diff. This shouldn't be a problem, right?

 

Get your struts checked... My 8 was making a knocking nose when I went over bumps (slow or not, like you say, speed didn't matter) and it turned out my rear struts needed to be replaced.

 

This is the sound it makes. I recorded a sound clip using my phone. Sorry about quality but you get the idea.

http://www.zshare.net/audio/69930078b2dd592c/

If you get bored forward to around 3:32, 3:39, 3:44 and 3:50.

 

sound quality isn't very good but that sounds like the noise mine was making. Get your struts checked out brother!

 

Sorry for the dumb question. How do you check struts? I mean what are the signs that they are failing?

 

moisture..

beers

 

None that I could see, although I will take another look just to be certain.