Infamous "M-Clunk" fixed, car shifts like brandnew!

tylernim · Sun, Jul-12-2009, 03:41:01 PM

never seen this thread before. glad it was bumped to the top. makes me rest easy all of the sudden.

lsrteg · Sun, Jul-12-2009, 04:38:38 PM

Quote:

Originally Posted by pjgo

PN 26122282495, center mount, aluminum, is #7 in the attached image. Thanks!

PJ

Thank you guys i hate that damn noise. Im doing it asap.

Krozi · Tue, Aug-04-2009, 09:08:24 PM

So this is a definite fix? How many other members have done this?

futballa10 · Thu, Aug-27-2009, 04:10:24 AM

Bump, really like this post, I was scared when i started hearing noises like that changing from 1st to 2nd. Didnt happen on my test drive of the car. Thought i bought a bad car

guess im not the only one with this clunking noise. Never new there was such thing as the "M-clunk".

Voodooking · Thu, Aug-27-2009, 10:12:50 AM

I really hate the M-Clunk. It embarrasses me when other people comment on it. Like for example if I'm parking at low speed and shifting from 1st to 2nd and passengers or colleagues say: "What's that noise, is there something wrong with your car?" and you have to explain that even though you have a nice car that people envy, it still makes a heap of clunky noises like an old wreck.

My car only makes the noise some of the time. I find that if the weather is hot it helps, the tranny is less noisy and more smooth. It's strange that it doesn't happen all the time.

I kind of think that the more you read up on it the more different reasons people give for it, and everybody suggests replacing something different. I would love for it to be gone, but feel I could spend a fortune replacing endless parts and still be in the same situation.

I do think however, that if I had bought my car brand new, paid £40k+ for it, and it had been the same clunky noisy mess there is no way I would have been happy. I would have taken it straight back to the dealer.

JWL · Thu, Aug-27-2009, 11:28:55 AM

I assume this only pertains to cars with a 6MT not an SMG.

JWL
2002
SMG
CB/B

**John_T** · Thu, Aug-27-2009, 11:50:24 AM

Quote:

Originally Posted by JWL

I assume this only pertains to cars with a 6MT not an SMG.

Pertains to all, as all are the same past the gearbox. You need to distinguish, however, between drivetrain play noises and the LSD clunk which is part of it's function in power distribution between the wheels, forward and reverse. The LSD clunk is not a constant and occurs only under certain functional circumstances. As stated in the SIB, there is deliberate play rear right.

bmwm3dave · Thu, Aug-27-2009, 12:02:49 PM

The M clunk drives me mad!
Here goes, Ive had the car 2 years its a 6MT 2001 with 53000 miles
3000 miles ago I had my clutch done, the flywheel was ok. Before this I had a mild clunk I considered acceptable. Since the clunk has become more noticeable.
If I have it in 1st or 2nd gear and accelerate decelerate by dabbing the pedal in quite rapid succession so the car takes up any play in the driveline both ways, there is a very noticable loose sounding clunk / clang coming from under the car and I must admit it sounds towards the front.
Its definately not suspension, subframe or anything like that, it is deffo the driveline or mounting points.
I am quite mechanically minded and take on most jobs myself but on this occasion I decided to take it to an independant BMW specialist garage.
They drove it, had it on the ramps, inspected what was visible, charged me £50 and said nothing to worry about everything is tight but there is wear in the diff. They showed me how it could be moved by turning the rear wheels and it did clunk a little.
They said put up with it, not worth changing till it breaks which it wont!

After all this I still read and have read every single clunking post on here.
I am still under the opinion it can be fixed.
Maybe there is two different issues one being the diff and the other being the driveline centre mount.
Does this sound familiar with anyone elses noises?
I'm interested to hear anything at all that might lead me to this annoying noise.
Dave

**John_T** · Thu, Aug-27-2009, 12:09:53 PM

Drivetrain is more clanky, LSD is more thud-clunk.

On any drivetrain, the play is taken up in one direction on applying power, then released and taken up in the other direction upon letting off power or shifting in reverse. Some play is normal and necessary, but in any case the noise will be reduced by the smooth applying or releasing of power.

MrKaira · Thu, Aug-27-2009, 12:15:32 PM

thanks for the info!

Thu, Aug-27-2009, 12:09:53 PM	#49
John_T Moderator Join Date: Mar 2005 Posts: 15,623 Reputation: 578 Location: Switzerland	Drivetrain is more clanky, LSD is more thud-clunk. On any drivetrain, the play is taken up in one direction on applying power, then released and taken up in the other direction upon letting off power or shifting in reverse. Some play is normal and necessary, but in any case the noise will be reduced by the smooth applying or releasing of power. __________________

Thu, Aug-27-2009, 12:15:32 PM	#50
MrKaira Registered User Join Date: Nov 2008 Posts: 38 Reputation: 0 Location: Richmond	thanks for the info! __________________ ///M3 - Dinan short shifter/ZCP wheels/DEPO smoked corners SS 350Z TT - Built motor/twin turbo

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Sun, Jul-12-2009, 03:41:01 PM	#41
tylernim Registered User Join Date: Jun 2009 Posts: 216 Reputation: 0	never seen this thread before. glad it was bumped to the top. makes me rest easy all of the sudden.

Tue, Aug-04-2009, 09:08:24 PM	#43
Krozi Hau Rein! Join Date: Jul 2009 Posts: 86 Reputation: 0 Location: Bonita Springs	So this is a definite fix? How many other members have done this?

Thu, Aug-27-2009, 04:10:24 AM	#44
futballa10 Registered User Join Date: Aug 2009 Posts: 117 In the garage: '01 BMW M3 Reputation: 0	Bump, really like this post, I was scared when i started hearing noises like that changing from 1st to 2nd. Didnt happen on my test drive of the car. Thought i bought a bad car guess im not the only one with this clunking noise. Never new there was such thing as the "M-clunk".

Thu, Aug-27-2009, 10:12:50 AM	#45
Voodooking Registered User Join Date: Jun 2009 Posts: 41 Reputation: 0 Location: Aberdeen	I really hate the M-Clunk. It embarrasses me when other people comment on it. Like for example if I'm parking at low speed and shifting from 1st to 2nd and passengers or colleagues say: "What's that noise, is there something wrong with your car?" and you have to explain that even though you have a nice car that people envy, it still makes a heap of clunky noises like an old wreck. My car only makes the noise some of the time. I find that if the weather is hot it helps, the tranny is less noisy and more smooth. It's strange that it doesn't happen all the time. I kind of think that the more you read up on it the more different reasons people give for it, and everybody suggests replacing something different. I would love for it to be gone, but feel I could spend a fortune replacing endless parts and still be in the same situation. I do think however, that if I had bought my car brand new, paid £40k+ for it, and it had been the same clunky noisy mess there is no way I would have been happy. I would have taken it straight back to the dealer.

Thu, Aug-27-2009, 11:28:55 AM	#46
JWL Registered User Join Date: Jun 2009 Posts: 98 Reputation: 0 Location: Gaffney	I assume this only pertains to cars with a 6MT not an SMG. JWL 2002 SMG CB/B

Thu, Aug-27-2009, 12:02:49 PM	#48
bmwm3dave Registered User Join Date: Nov 2007 Posts: 43 Reputation: 0	The M clunk drives me mad! Here goes, Ive had the car 2 years its a 6MT 2001 with 53000 miles 3000 miles ago I had my clutch done, the flywheel was ok. Before this I had a mild clunk I considered acceptable. Since the clunk has become more noticeable. If I have it in 1st or 2nd gear and accelerate decelerate by dabbing the pedal in quite rapid succession so the car takes up any play in the driveline both ways, there is a very noticable loose sounding clunk / clang coming from under the car and I must admit it sounds towards the front. Its definately not suspension, subframe or anything like that, it is deffo the driveline or mounting points. I am quite mechanically minded and take on most jobs myself but on this occasion I decided to take it to an independant BMW specialist garage. They drove it, had it on the ramps, inspected what was visible, charged me £50 and said nothing to worry about everything is tight but there is wear in the diff. They showed me how it could be moved by turning the rear wheels and it did clunk a little. They said put up with it, not worth changing till it breaks which it wont! After all this I still read and have read every single clunking post on here. I am still under the opinion it can be fixed. Maybe there is two different issues one being the diff and the other being the driveline centre mount. Does this sound familiar with anyone elses noises? I'm interested to hear anything at all that might lead me to this annoying noise. Dave