Weird clunk?! Especially starting in reverse!

[Gregg]

I noticed today for the first time that when I start off (especially in reverse) I feel and hear a clunk sound coming from the rear of the car!! :eek: :( HELP!! Any ideas?

Thanks
Gregg

[SQ Bimmer]

Make sure your diff bolts are all tight.

[Gregg]

Yeah I am going to limp down to MSR tomorrow and check them out. Arrgh!!

[the transporter]

yup been here a few times it sounds like the diff bolts I am considering building a special tool for this job and haven't done it yet but you could maybe and try if you want. it is a tight fit on the upper bolts due to the sway bar so a ratchet with socket don't fit and it is kinda a pain removing the sway bar (done this) so my idea was buy an 18mm socket get a long piece of like 1/4 by 2 flat bar about 1' to 1'1/2" long and weld the socket flat to it out at one end you wouldn't have ratcheting but it may fit between sway bar and save alot of work don't know haven't tried it yet but I also know that there is a kit you can buy to basicly solid mount the diff so it won't loosen the bolts up again.

[boltsm3]

check u-joints also

[WytLytnyn]

Check your rear ball joints. I heard a clunk everytime I put the car in reverse and rolled back about a foot.

I suspected the RTAB's were shot (which they were) and had them replaced. The problem still occurred and then the shop checked the rear ball joints. Sure enough, they were trashed as well. Upon replacement, the problem ceased and the rear end is so much more stable when accelerating and cornering (obviously).

[SQ Bimmer]

Which ball joints are you referring to?

[Gregg]

My front diff bolt was bent slightly but I still have the noise. Argh. Why are these cars so damn fragile? I have a 300ZX TT that I beat the crap out of that was still running strong at 175K and all I did was change the oil and brake pads. Oh, and one clutch. I am starting to see the BMW's are money pits perspective.

Anyone want some genuine csl/zcp's with pilot sport 2's? LOL

[Mr. White]

You sure it's coming from the rear? My first guess would be your flex disc is causing the clunk.

[odortiz]

i have the same thing on my 325. the right side inner cv joint has play and is on its way out. when under there, try to twist the shaft while holding the outer part of the cv joint you will feel play if it's there. (twist hard)