clunk when cluth pedal is depressed

I hear a loud clunk (seems to be coming from the middle to the rear underneath the vehicle) every time I press (disengage) on the clutch pedal too fast or when I release (engage) it too fast. It's more predominant from reverse to 1st gear and 1st to 2nd gear but i can hear it throughout the gears. I'm able to make it go away most of the time if I put more gas while pressing the clutch pedal and when i release the clutch pedal slower. there are no leaks, no other noise, nor a service engine light what so ever. This is not my first time driving stick. Has anyone experienced the same thing with their X3? I've heard some from the M3 folks but never with X3s.
Note: I am able to put the car in gear with no grinds or any difficulties, the noise comes from the clutch engaging and disengaging. it sounds like the whole transmission is going to drop when i hear that clunk. No affect on drivability at all. thanks


2004 X3 6MT w/89K miles

Transfer case mount, diff mount, or subframe bushing.

I had the same thing. So if sitting in start stop traffic
then happening all the time.
In and out of dealer several times with no joy.
Eventually they agreed to change transfer box under warranty
and problem seemed to go away for a time , but eventually
same symptom returned.
Eventually found on forum someone suggested
tyre wear or differing types of tyre from
front to back can cause issues. Needed some new tyres on front
and replaced both. Wouldn't have believed
it but noise at declutch has now completely gone!!

i took it to the dealer 3 weeks ago and had one of the SA ride with me so he can hear the clunk. He said he hears it, but doesn't know what it is since they never had this problem with any of their x3s ( actually, he said they never had to service an x3 with manual transmission before). I have checked all of the mounts ( engine, transfer case, rear diff) and they looked/felt okay , although i may not have enough expertise to provide a proper diagnosis. The SA did say that i shouldn't be too worried about it and recommended to have one of the mechanics check it when i go in for an oil change..(in about 3K more miles)

I have fairly new conti tires (about 5K miles) which are same all around, so i'm doubting if the tires that's causing the clunk. so right now, im just ignoring it and just wait it out until it's time to change the clutch.

I wish it was tires that fixed mine, i'm guessing its a clutch. I remember in my toyota supra where in the middle of the driveshaft there was a center bearing like middle mount that would wear out and hit during hard shifts. I even get my noise after I have already switched out of gear and am slowing down then it makes the noise without me doing anything. I thought it could be a slave/master cylinder, clutch, trans mount, transfer case mount. so many things it could be. This flyby wire stuff has a mind of its own so i'm not sure if its what i'm doing or something really warn. (all gibberish sorry)

Another possibility is a worn guibo.