Clunk when shifting hard in the M coupe

Hellred · #1 (**permalink**) 02-25-2002, 01:31 PM

Anyone experience this. Sounds like a diff or tranny mount. Anyone have any feedback?

Thanks,

Greg

The Judge · #2 (**permalink**) 02-25-2002, 01:38 PM

I know some of the new BMW's like the M3 have a clunking noise in the differential, but it's perfectly normal.

Hellred · #3 (**permalink**) 02-25-2002, 01:42 PM

This is a 99 though. Not exactly new. New to me

The Judge · #4 (**permalink**) 02-25-2002, 01:49 PM

Im willing to bet that it is the same technology as the newer ones. Mine also makes an occasional clunking noise. But its usually easy to tell if it is from the diff. It will happen speeding up out of corners and when you switch gears.

Dudenarley · #5 (**permalink**) 02-25-2002, 02:25 PM

My dad has a new M3 and the shifts are a bit noisy sometimes. Alot of high performance cars like ferraris do it as well.

rhyswynn · #6 (**permalink**) 02-25-2002, 03:15 PM

I get that sometimes in first and second, maybe a little bit in third...not even when shifting hard, it seems like when I disengage the clutch really fast, its strange.

So that is fairly normal for M's? Good, I thought something was wrong...haven't noticed it the last few days though.

IlllIlI · #7 (**permalink**) 02-25-2002, 05:05 PM

yea i notice this when disengaiging the clutch quickly too, i think it could be one of the following..
loose diff. mounts
worn diff. mounts
worn flex disk (gubio)

this weekend i'll re-torque the diff. mounts and let you all know if it solved the clunking problem..

SG_M3 · #8 (**permalink**) 02-25-2002, 05:40 PM

the clunk in the new m3 is due to the m variable lock diff. So a clunk in a s52 car would not be normal.

Tampaturbom3 · #9 (**permalink**) 02-25-2002, 06:13 PM

!!!!!!!! if you are getting a "clunk"when accelerating and decelerating, it may very well be a broken subframe. I broke a diff bolt and then it separated the steel that makes the subframe. the bolt breaking will cause a clunking noise too (ask Jon Caldito, his did this too). I would take it to the dealer and have them inspect the subframe. Mine broke where the subframe mounts to the car in the rear, drivers side spot. on the top, the steel separated at the seam. it's hard to see it unless you know what you are looking/feeling for. If it is this and you drive you will most likely contort the differential to where it damages the 1/2 shaft and other components (ask me how i know). if it's the bolt, and i hope that it is, it's an easy fix. the 99's bolts are prone to this (ask jon).
another clunking noise can be the shock tower mount, but that would clunk on hitting bumps, not on acceration or deceleration. if the noise is closer to the front, then the driveshaft ujoint (carrier bearing area) is probably shot.
i'm betting on the diff bolts

The Judge · #10 (**permalink**) 02-25-2002, 06:40 PM

I agree with SG M3. It has to do with the limited slip. Happens in anything from Camaro to Aston Martin. Completely normal.

The Judge · #11 (**permalink**) 02-25-2002, 07:03 PM

Quote:

Originally posted by Tampaturbom3
!!!!!!!! if you are getting a "clunk"when accelerating and decelerating, it may very well be a broken subframe. I broke a diff bolt and then it separated the steel that makes the subframe. the bolt breaking will cause a clunking noise too (ask Jon Caldito, his did this too). I would take it to the dealer and have them inspect the subframe. Mine broke where the subframe mounts to the car in the rear, drivers side spot. on the top, the steel separated at the seam. it's hard to see it unless you know what you are looking/feeling for. If it is this and you drive you will most likely contort the differential to where it damages the 1/2 shaft and other components (ask me how i know). if it's the bolt, and i hope that it is, it's an easy fix. the 99's bolts are prone to this (ask jon).
another clunking noise can be the shock tower mount, but that would clunk on hitting bumps, not on acceration or deceleration. if the noise is closer to the front, then the driveshaft ujoint (carrier bearing area) is probably shot.
i'm betting on the diff bolts

I doubt that would be a problem NA cars. Offcoarse your going to bust something with the power you have.

Hellred · #12 (**permalink**) 02-25-2002, 07:26 PM

I've experienced a broken subframe on my 325, and now every car I buy, I check for signs of that. My technician buddy checked the car for that on the lift prior to purchase. We loaded the diff up my keeping the brakes applied, and loading and unloading the drivetrain repeatedly to see what was clunking, but there was nothing apparent.
The car will be going in for a few warranty items, and I'll have my buddy poke around some more.
I'd like for them to figure it out prior to modifying the car. We all know how dealers get when they see mods...

It does occur with quick shifts.

Sounds like a bad mount or a worn bushing...

Thanks for the feedback.

Greg