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Discussion Starter #1 (Edited)
I searched up "clutch clunk", read all the results but didn't find a complete answer.

Basically, when the car is in gear and I depress the clutch pedal, I hear a clunk. It's not disconcertingly loud, but enough to be noticeable cause the rest of the car is so silent. It is most obvious in first gear. Say I'm stuck in traffic, I'm creeping forward (clutch not completely engaged) with light throttle and then decide to stop. Press the clutch in and I hear a clunk. Even if the clutch is fully engaged and I'm rolling in 1st then decide to stop, I get the clunk anytime I want to disengage and press in the clutch pedal. Is this normal? In fact, even when I'm decelerating to a stop, from 2nd gear, I hear a clunk upon disengagement.

All the manual cars I've had did this to some extent or another, but the M5 seems to do it more often or more obviously. The car was purchased recently with 12.5k miles. It was enthusiastically driven by previous owner (evidenced by rear tyres that are almost down to wear bars), so there is concern the clutch might have taken some abuse.

However, clutch pedal feels completely smooth, does not stick, does not catch something on the way up, does not squeak, and I've seen no signs of slipping. It just seems rather touchy (not the easiest car to do smooth shifts in) and I get that clunk.

Some search results mentioned a "Driveline lash". What exactly is this? Is it what I'm describing?

Thanks for any help you can provide.
 

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I just had my prop shaft replaced under warranty. It was the cause of significant shunt/backlash/free-play/whatever-it's-called since brand new, and I assumed it was what was meant when people talked about a notchy or clunky transmission. The prop shaft was only diagnosed when a bearing gave up the ghost.

I had already had a new gearbox and diff, to no effect.

The difference is like night and day. The gearbox is still big, heavy and clunky (supposedly like they all are) but, boy oh boy, the whole experience is so much nicer.
 

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Discussion Starter #3
gmajor said:
I just had my prop shaft replaced under warranty. It was the cause of significant shunt/backlash/free-play/whatever-it's-called since brand new, and I assumed it was what was meant when people talked about a notchy or clunky transmission. The prop shaft was only diagnosed when a bearing gave up the ghost.

I had already had a new gearbox and diff, to no effect.

The difference is like night and day. The gearbox is still big, heavy and clunky (supposedly like they all are) but, boy oh boy, the whole experience is so much nicer.
Were your symptoms similar to mine?
 

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What it sounds like to me is the tranny mounts unloading when you put the clutch in. Most manual cars will have some drive train lash (movement in the tranny mounts, diff mounts, u joints etc) that will cause the car to pogo a bit when you put the clutch in. It should be very minimal though, and not cause any noise.
I would take a look at the tranny and diff mounts. What you are describing isnt clutch related in my experiance, rather it is related to free play in the drivetrain. Another way to deal with it in the mean time is dont put the clutch in when you are off throttle. When you are off throttle the mounts get torqued due to the deceleration, and when you put the clutch in the mounts all relax. If they are worn, what usually happens is what you are describing. Keep some throttle in as you put the clutch in (just a touch) and it should help. I dont remember the E39 having a lot of drivetrain lash, so I would get the car looked at, with emphasis on tranny and diff mounts. Also do a board search, as some people around here are running aftermarket tranny mounts with a lot of positive reviews.
:cheers:
 

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It could also be either a driveshaft bearing or the guibo (flex disk coupling). It's most likely somewhere in the driveline aft of the transmission and could be any of the things others have posted above. Have everything aft of the tranny checked.
 

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Replying to earlier question...

On pushing the clutch down, and lifting it back up, there was quite nasty clunking and backlash-type noises and feelings. To be honest, it seemed to come from points all along the drivetrain, but was finally diagnosed as the centre and rear bearings of the propshaft.
 
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