Clunk noise as I pull away...?

[born2boost]

Hi Guys...

I am experiencing a light clunk noise when pulling away....what could it be? I've already upgraded the rear trailing arm bushes to Poly ones...

It sounds like it could be coming from the diff area?

Are there any common failure area's I should look at??

TIA...

[shane@mbtech]

Hi Guys...

I am experiencing a light clunk noise when pulling away....what could it be? I've already upgraded the rear trailing arm bushes to Poly ones...

It sounds like it could be coming from the diff area?

Are there any common failure area's I should look at??

TIA...

The diff itself could be fubar-ed

[sailorbaz]

It probably is the diff, I'd get it checked out but wouldn't be overly worried about it. I got a new diff under warranty and even it clunks after only a couple of thousand miles. But best get it checked out to settle the head.

[Barry C]

hardly a tare in the boot floor?:bigcry: get it checked out asap either way

[NZ_M3]

Could be the diff bush itself (the front one or the rear left I think, can't recall) these go quite often.

Or worst case ripped rear floor can cause these type of noises too - pay to put the car up on the hoist to check.

The other possibility is the driveshaft rear bearing joint (the one connecting to the diff directly - check if there's excessive play.

If it's not the driveshaft, CV joints on the half shafts could cause this noise also - common failures.

[born2boost]

Hi guys...

Thank you for all the input...!

Had the car out at my (Ex BMW) mechanic...he's baffled about it as well...the cars not torn anywhere as is common, and all the bushes and mounts seems fine?

I guess I need to get the driveline checked...

Would an oil change in the diff help at all??

Thanks again...

[DuncanR]

Would an oil change in the diff help at all??

Thanks again...It would if there is fook all in it !!! but doubt it ... mines had 3 diffs and I would bet thats what is wrong with yours ... drive along about 25~30 mph, let the car just coast, and then blip the throttle to take up the drive again and listen...report back !:clown:

[born2boost]

I've just got the car back from him...and was driving around...trying figure exactly when it happens...

It seems that the noise occurs just as I accelerate...I guess its the diff thats taking up the back lash on the gears inside before actually engaging??

Is there any fix for this problem other then changing the complete diff???

Man I hate that noise :(

[DuncanR]

Is there any fix for this problem other then changing the complete diff???Green bananas mate im afraid ... its the only way if you dont want to pay !
Shove 3~4 green bananas and the peel through the oil filler hole....:smokin:

[giraffe]

Green bananas mate im afraid ... its the only way if you dont want to pay !
Shove 3~4 green bananas and the peel through the oil filler hole....:smokin:
Loving the green bananas not used that 1 before , as many people said on here normally diff itself . Diff oil change would only make a diffrence if you had grinding noise on full lock if it klunk oil wont fix fault .

[billyboysm3]

Green bananas mate im afraid ... its the only way if you dont want to pay !
Shove 3~4 green bananas and the peel through the oil filler hole....:smokin:

Brilliant

[mattCSLnut]

Green bananas mate im afraid ... its the only way if you dont want to pay !
Shove 3~4 green bananas and the peel through the oil filler hole....:smokin:
You sure 3-4 would be enough mate ? :hahaha: ;)

[E46CSL]

You sure 3-4 would be enough mate ? :hahaha: ;)

A pair or two of stockings will also help :whistle:

[jonv]

Mine did exactly the same, but it was the trailing arm that went up into the body.

I thought the worse and contemplated the diff support.

Something had come lose. So the mechanic lowered the bush housing, tightened something up, problem fixed!!

[born2boost]

Mine did exactly the same, but it was the trailing arm that went up into the body.

I thought the worse and contemplated the diff support.

Something had come lose. So the mechanic lowered the bush housing, tightened something up, problem fixed!!

Thats interesting...because I did have poly bushes fitted to the RTA's...could you perhaps elaborate on what could have come loose?

Thanks for the info...!

[jonv]

Having spoken with the mechanic, he says it was the front of the rear trailing arm bush bolt that was lose. This caused the clunking sound on accelerating as you described.

To fix this, he had to lower the supporting braket (marked first to avoid changes to allignment) as you cannot get a spanner in there and just tightened the bolt up, problem fixed!!

As you did, I thought this was the diff and the dreaded diff mount issues, but the tightening of a loose bolt fixed it!

[s.mac]

I've forgotten what is like to pull away in a CSL :(

[Bounce]

I've forgotten what is like to pull away in a CSL :(You going to bring it to Silverstone for a run out.:whistle:

[s.mac]

I want to but Im not sure I will have run it it :bigcry:
I sent the suspension off for a service and they have taken longer than expected to get back :banghead: not happy but too much going on to worry about it, or to chase it with anger :(

[shane@mbtech]

Bring it down to my gaffe Steve. I can do 300 miles a week back and to, to work. Just gentle motorway/town driving.

Im being serious, and I will be gentle with her:beer:

[s.mac]

its up in the air mate on jacks, wheels off, suspension off, gone for re build.
Chased AST, they've had it for 6 weeks minimum :banghead: getting well pissed off with them.
Had the bull shit that they were being sent out for the last 3 Fridays :banghead: I get tied up with things during the week and before I know it Fridays here again, which is when I call, 4th Friday this week :banghead:
Otherwise I would be running it with all this good weather we're having

[born2boost]

Just thought I'd update this thread....

I took the car to another BMW Mechanic here and it seems that the diff was loose!! He tightened it all up and the car seems much better now!!

:whistle: