Clutch Disengage Thud/Clunk

[andrews]

Hi everyone,

I took my car in today to have the dealership investigate what I would describe as a thud or clunk sound made when I disengage the clutch (push the pedal in). It seems to only happen at low speeds (1st or 2nd gear) and I usually notice it when turning, like trying to park, but it does happen when the car is going straight as well. I suppose it could happen at higher speeds and I don't notice because of road noise, but I feel like it's loud enough that I might be able to hear it happen in 3rd or 4th depending on the road.

Anyway the dealer said they tested on another M car (not the 1M specifically because it turns out they are in short supply ) and it was completely normal.

Anyone else experience this? Is there anything I should/can check myself once I get the car back?

[///Mbedded]

I get the same thing. It's usually in 1st or 2nd. Haven't ever heard it in higher gears... but it might just be overpowered by the sound of the exhaust, road noise, Harman Kardon sound system, etc.

[dcb]

Same here...It is even called out in the 1M supplementary manual.

[Maximus_Prime]

My car does it too... it always happens when shifting from first to second gear for me. It feels like the transmission takes a major dump.

I noticed that it usually happens when I shift out of 1st quickly - and always results in a neck-jarring jerk when I get into 2nd. It's actually pretty annoying, and the only way I've found to avoid it is to shift out of 1st really slowly, which is not really what you want to do in a 1M.

[HALOTHANE]

Absolutely 100% NORMAL. It is common while short-shifting 1st to 2nd. This is due to the dual-mass flywheel. Source: BMW M mechanic who also tracks these cars.

P. S. The LSD will also make a grinding noise on slow R hand turns. Also NORMAL and a sign of proper function.

Several old posts regarding both topics.

[wkndwrrr]

Originally Posted by 1MVO

Absolutely 100% NORMAL. It is common while short-shifting 1st to 2nd. This is due to the dual-mass flywheel. Source: BMW M mechanic who also tracks these cars.

P. S. The LSD will also make a grinding noise on slow R hand turns. Also NORMAL and a sign of proper function.

Several old posts regarding both topics.

I've been hearing a grinding noise on slow right turns, and I thought I was rubbing!

[Fundahl]

My car makes this weird vacuum sound and sounds like something is roaring from the back of my car when I got WOT. Is that normal or should I bring it in to the dealership?

[flzrider]

I get the same noise, however, I noticed that it is especially noticeable on the very 1st shift of a driving session (when starting with a cold motor). Anyone else notice that?

Originally Posted by 1MVO

Absolutely 100% NORMAL. It is common while short-shifting 1st to 2nd. This is due to the dual-mass flywheel. Source: BMW M mechanic who also tracks these cars.

P. S. The LSD will also make a grinding noise on slow R hand turns. Also NORMAL and a sign of proper function.

Several old posts regarding both topics.

I, too, think it's normal, but I honestly don't think it is the DMF. I've owned/driven other cars with DMFs and never had that noise. I think it is elsewhere in the drivetrain. And like dcb said, it is mentioned in the 1M supplement. Also, I thought the LSD groan was either left or right turns, not specifically one or the other.

Originally Posted by Fundahl

My car makes this weird vacuum sound and sounds like something is roaring from the back of my car when I got WOT. Is that normal or should I bring it in to the dealership?

lol I can't tell if you're being sarcastic or not.

[silvs]

I got this same noise in a previous 328i. If I ease out of first it doesn't happen, same thing here with the 1M. Pretty sure DMF.

[RaptorKTM]

This off the bat sounds 100% normal. Another complaint ive seen is at very low speed a clunk from disengagement. That all has to do with load on the transmission. A good test to see if this goes away is to go keep 1-3% throttle while shifting, just barely any gas, do not completely unload the transmission, see if that makes any difference when moving slowly. If not the clunk is the gears loading and unloading then clunking when disengaging the two. Hope this made any sense at all.

[DooBs]

I too get this clunkish sound when depressing the clutch at low speeds and 1st. Never heard any grinding or clunking in higher gears.
However when going WOT from 1st to 2nd its a bit difficult to change into 2nd (shifter won't go in) 2nd to 3rd and on are perfectly fine though.

[m3kerry]

I did not read the whole thread, but you are hearing noises causes by the way the cdv works. It is normal as long as the cdv is in place on the car. Have it pulled after the warranty runs out.

[flzrider]

Originally Posted by m3kerry

I did not read the whole thread, but you are hearing noises causes by the way the cdv works. It is normal as long as the cdv is in place on the car. Have it pulled after the warranty runs out.

Do you have yours removed? If so, did the noise go away after removal?

By the way, you can always remove the restrictor in the CDV and re-install, so it appears untouched.

[Maximus_Prime]

Originally Posted by RaptorKTM

This off the bat sounds 100% normal. Another complaint ive seen is at very low speed a clunk from disengagement. That all has to do with load on the transmission. A good test to see if this goes away is to go keep 1-3% throttle while shifting, just barely any gas, do not completely unload the transmission, see if that makes any difference when moving slowly. If not the clunk is the gears loading and unloading then clunking when disengaging the two. Hope this made any sense at all.

I think I understand what you're saying - and totally agree. I was trying to write the same thing but decided it was too complicated to explain. Basically, I have been able to successfully avoid the thunk by using the technique you described (i.e., depressing the clutch right before I completely remove foot off accelerator, so that I am lightly on the throttle as I push down on the clutch). This seems to avoid the thunk 95% of the time, but needs practice to get it right each time.

Originally Posted by flzrider

I get the same noise, however, I noticed that it is especially noticeable on the very 1st shift of a driving session (when starting with a cold motor). Anyone else notice that?

I've noticed that too.

Originally Posted by DooBs

I too get this clunkish sound when depressing the clutch at low speeds and 1st. Never heard any grinding or clunking in higher gears.
However when going WOT from 1st to 2nd its a bit difficult to change into 2nd (shifter won't go in) 2nd to 3rd and on are perfectly fine though.

Same here. Actually, I almost always encounter hesitancy when shifting from 1st to 2nd. When the car is cold, I've got to really force the shifter into 2nd. I've noticed that if I use the above technique to avoid the thunk out of 1st, then the transitions into all gears become much smoother.

One last thing, I've also noticed that changing between gears is like butter when I am stopped at a light, but it gets harder/less silky to shift into gears when the car gets moving. Anyone have an explanation?

[speedM]

Originally Posted by andrews

Hi everyone,

I took my car in today to have the dealership investigate what I would describe as a thud or clunk sound made when I disengage the clutch (push the pedal in). It seems to only happen at low speeds (1st or 2nd gear) and I usually notice it when turning, like trying to park, but it does happen when the car is going straight as well. I suppose it could happen at higher speeds and I don't notice because of road noise, but I feel like it's loud enough that I might be able to hear it happen in 3rd or 4th depending on the road.

Anyway the dealer said they tested on another M car (not the 1M specifically because it turns out they are in short supply ) and it was completely normal.

Anyone else experience this? Is there anything I should/can check myself once I get the car back?

perfectly normal, with my experience with bmws. the 1-2 shift in this car rewards smoothness. depress the clutch with a fluid action while letting off the gas for the shift, and it's smooth as butter. i only encounter a thunk when i have to abruptly depress the clutch in first (ie. avoidance maneuver).

[Fundahl]

Originally Posted by flzrider

lol I can't tell if you're being sarcastic or not.

I was describing induction and exhaust noises. Just a joke.

[DrSpock]

I am glad I'm not alone on this, I too notice a very audible "CLUNK" when depressing the clutch for the 1st to 2nd gear transition. It does seem to be accentuated when the engine is cold.

You can feel the "CLUNK" too which isn't too attractive of a sound or feeling in the car. Smooth clutch action seems to lessen the effect quite a bit.

3rd gear and up and very smooth.

What is the optimal shift RPM from first to second? I was playing around with it not sure if I was shifting too soon or too late that was causing the sound.

[Dan Parker]

Open CDV = Gone

[AA5IB]

Originally Posted by Dan Parker

Open CDV = Gone

Yep.

[m3kerry]

Originally Posted by flzrider

Do you have yours removed? If so, did the noise go away after removal?

By the way, you can always remove the restrictor in the CDV and re-install, so it appears untouched.

Not on this car. The class it races in will not allow it.

[Romo]

It is a normal sound if you lift too early on the accelerator.......this means that if the sound is present, you don`t shift the way it`s supposed too.

Just lift a little bit, or put more pressure on the accelerator, the sound will be gone..........smooth like silk shifting........

It is not that hard..........just practise.......

I drove an E46 M3 whit a clunck, I had to learn it too

[flzrider]

Originally Posted by Dan Parker

Open CDV = Gone

Originally Posted by AA5IB

Yep.

I guess I have my weekend project lined up.

Any tips on bleeding the system? You guys use the old school method or something else?