Light knocking noise from the chassis - Page 2

TANKSLAPPER · 17-03-2009, 04:48 PM

Hi Bryce

I am familiar with the knocking noise you get with SMG at lower speeds, It's definitely not that.

Thanks anyway

TANKSLAPPER · 27-05-2009, 01:29 PM

Finally think I have found the noise with help of ETA motorsport at Brands Hatch
They reckon it is coming from the right hand drive shaft inside the rear diff
We changed the diff oil and the noise is slightly less now.

This fits the description I gave:-
“light knocking noise, only when it has warmed up, the hotter it gets or the longer the run the noise is louder.
I can only hear the knocking when the car is freewheeling and slowing down in a straight line from about 35mph to 5mph ie with no load”

So I need a new diff and drive shafts, has anybody got a view on how I should go about it.

ie. Try my luck with BMW for a good will warranty claim, Reconditioned, new, change the final drive ratio’s,

And does any one know the likely cost ?

**Mark CSL** · 27-05-2009, 03:07 PM

Try bmw for a good will or buy a warranty and then discover the noise

derek · 27-05-2009, 07:17 PM

Hi i got a new diff last month i think it was £1800+vat+fitting, its was covered with the warranty, car is so much quieter and no clonking at slow speeds with no drive

lfc · 27-05-2009, 08:56 PM

Almost certainly the pads running extra feely in the calipers. Its no problem but an annoying noise. It happened to me on my M6 when I fitted Brembos. Look on the bright sde - less drag!

bryce · 28-05-2009, 10:57 PM

I get these symtoms too tankslapper. You think you'll get a new diff?

Derek, what was your symtoms and many miles your car got?

derek · 29-05-2009, 09:56 AM

Quote:

Originally Posted by bryce

I get these symtoms too tankslapper. You think you'll get a new diff?

Derek, what was your symtoms and many miles your car got?

the car did clonk at little with no drive at low speed, there was found to be more movement on the diff than another m3 the garage compared it too, mileage was 38k, Big difference in the driving noise level and s6 changes

TANKSLAPPER · 14-07-2009, 12:41 PM

I finally solved the knocking noise.

The piston in the front suspension was knocking.

Remedy was to adjust the front coil overs up by 1mm

spend months trying to solve this, and it only took 5 min to sort it.

Now working as new.

27-05-2009, 03:07 PM	#13
Mark CSL CSL Register Uber-poster! Join Date: Sep 2007 Location: Scotland Posts: 8,777 Casino cash: $42229	Try bmw for a good will or buy a warranty and then discover the noise __________________ www.procarkits.co.uk

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17-03-2009, 04:48 PM	#11
TANKSLAPPER S5, Sport Off, DSC M-track Join Date: Nov 2008 Posts: 801 Casino cash: $8979	Hi Bryce I am familiar with the knocking noise you get with SMG at lower speeds, It's definitely not that. Thanks anyway

27-05-2009, 01:29 PM	#12
TANKSLAPPER S5, Sport Off, DSC M-track Join Date: Nov 2008 Posts: 801 Casino cash: $8979	Finally think I have found the noise with help of ETA motorsport at Brands Hatch They reckon it is coming from the right hand drive shaft inside the rear diff We changed the diff oil and the noise is slightly less now. This fits the description I gave:- “light knocking noise, only when it has warmed up, the hotter it gets or the longer the run the noise is louder. I can only hear the knocking when the car is freewheeling and slowing down in a straight line from about 35mph to 5mph ie with no load” So I need a new diff and drive shafts, has anybody got a view on how I should go about it. ie. Try my luck with BMW for a good will warranty claim, Reconditioned, new, change the final drive ratio’s, And does any one know the likely cost ?

27-05-2009, 07:17 PM	#14
derek S5, Sport On, DSC M-track Join Date: Jun 2008 Location: Scotland Posts: 1,159 Casino cash: $20658	Hi i got a new diff last month i think it was £1800+vat+fitting, its was covered with the warranty, car is so much quieter and no clonking at slow speeds with no drive

27-05-2009, 08:56 PM	#15
lfc Mode S1 - Starting Out Join Date: Sep 2007 Posts: 2 Casino cash: $5785	Almost certainly the pads running extra feely in the calipers. Its no problem but an annoying noise. It happened to me on my M6 when I fitted Brembos. Look on the bright sde - less drag!

28-05-2009, 10:57 PM	#16
bryce S5, Sport On, DSC M-track Join Date: Nov 2008 Location: Scotland (sw) Posts: 1,369 Casino cash: $2512	I get these symtoms too tankslapper. You think you'll get a new diff? Derek, what was your symtoms and many miles your car got?

14-07-2009, 12:41 PM	#18
TANKSLAPPER S5, Sport Off, DSC M-track Join Date: Nov 2008 Posts: 801 Casino cash: $8979	I finally solved the knocking noise. The piston in the front suspension was knocking. Remedy was to adjust the front coil overs up by 1mm spend months trying to solve this, and it only took 5 min to sort it. Now working as new.