320D E90 - Thud when accelerating

[F2004M]

Any help would be a huge.

I recently started to get a 'thud' when accelerating from a stop, never happens when braking.

Garage have swapped out the differential, prop shaft, drive shafts and it's still making the thud.

Any ideas what it could be? it's the drivers rear/right it appears to come from?

Cheers

[goldieandblackie]

Propshaft Doughnut !

https://www.google.co.uk/search?q=bmw+e90+propshaf...

[Elliot2000]

High mileage? Subframe bushes?

[F2004M]

goldieandblackie said:

Propshaft Doughnut !

https://www.google.co.uk/search?q=bmw+e90+propshaf...

Changed this with the replacement prop shaft :-(

[F2004M]

Elliot2000 said:

High mileage? Subframe bushes?

230K, they stuck it on the a machine which shakes the chassis but no sounds or nothing hanging off.

Having to order some new rear bushes to see if that's the issue but it's getting expensive.

Thud only happens when you accelerate, never under braking.

[Elliot2000]

It won’t happen on shaker plates. It doesn’t take long to check the bushes - 15 minutes - have a support under the subframe and remove the bolts one at a time - it should be fairly obvious by looking at the bush to see if they are knackered

[F2004M]

Elliot2000 said:

It won’t happen on shaker plates. It doesn’t take long to check the bushes - 15 minutes - have a support under the subframe and remove the bolts one at a time - it should be fairly obvious by looking at the bush to see if they are knackered

Well the garage has now ordered some bushes in from Germany (not sure on the type) so if this doesn't fix it I may give up.

The garage have been great and I understand that sometimes troubleshooting isn't easy despite the lay out.

[Elliot2000]

Bushes no. 2 and 3 is the ones I suspect maybe the cause

[NicheMonkey]

car sounds familiar, is the reg KV06 *** ??

[F2004M]

Elliot2000 said:

Bushes no. 2 and 3 is the ones I suspect maybe the cause

Interesting!

The Bushes they are ordering at 5-10 days shipping from Germany so fingers crossed.

They initially believed it was the differential but I went the whole hog and went for replacement diff (off a 1 series) along with a newer prop shaft and completely new drive shafts.

My diff had no oil in it anyway when they checked so likely needed to be replaced anyway.

Fingers crossed it is the bushes causing the 'thud'

[F2004M]

NicheMonkey said:

car sounds familiar, is the reg KV06 *** ??

No I'm afraid

It is an 06' though.

[F2004M]

Got my car back - all fixed!

Turns out the knocking *was* the 'big' bush connected to the diff which was 'thudding'.

Spent over 1k but the replacement diff, prop shafts, drive shafts which were likely needed anyway after 230k miles.

[thatdude]

Interesting the garage didnt go looking for the simpler stuff first!

[F2004M]

Perhaps but I trust the garage and they heavily discounted the bushes and were apologetic.

To be fair when they took off my original diff they said it was knackered and had no oil in it so maybe a blessing I replaced it.
In my own job I troubleshoot and make suggestions on how I think the issue is and don't always get it right.

The whole car feels much tighter now and I'll continue use the same guys