Help Needed - '95 M3 Metal Rubbing and Rapid Tapping Noise Coming from Trans Tunnel

[countryboyshane]

Hello everyone! I am seeking help from the resident experts here on a bad rubbing and tapping noise I am hearing from my 1995 BMW M3 race car's transmission tunnel. I've searched the forums and am mostly finding old posts that have no audio or video.

Video
https://youtu.be/YB9Z3sw14QY

One important comment - I am by no means a BMW E36 enthusiast. This platform is very new to me, but I can learn quickly from many years wrenching, racing, and tweaking cars.

This is a 1995 BMW M3 with a S54 engine and ZF 5-speed transmission. I believe I'm the 5th owner of this car. Guy who previously owned it must have bought every E36 part under the sun from Bimmerworld and Turner (not complaining)! After buying the car, I only was able to drive one test & tune day at Mid-Ohio Sports Car Course before I noticed this very bad noise coming from the transmission tunnel. It was so concerning that I put the car back in the trailer after only 5 sessions out of fear something was going to burst into a billion pieces and cause thousands of dollars in damage. I can physically feel vibration and "tapping" when I put my hand on the transmission tunnel. The guibo disk is intact. When I'm coasting, the noise stops. It's only occurring when accelerating.


TURN YOUR BASS DOWN.


Most noticeable at:
0:32
1:25
1:48
2:34
3:06
4:07


Before I start to tear stuff apart, and most importantly buy stuff, would like to get everyone's opinion on what could be the root cause. What do you think?

[importbanana]

driveshaft center support bearing

driveshaft u joints

check that

[XnWarden]

Are you running poly trans mounts?

Sent from my SM-G975U using Tapatalk

[blckstrm]

driveshaft center support bearing

driveshaft u joints

check that

+1

If your flex disc is new, that's about all there is left to check. I highly doubt it's either the tranny output shaft or the diff input shaft, but you could wiggle them to check.

Is this speed dependent or rpm dependent (given the comment about not being able to hear it well in first, it seems speed dependent). It seems it needs some load, but does the vibration change as you go faster in a different gear?

[saucey]

personally I am doing some driveshaft work right now, if it isnt your daily, put it on stands, remove exhaust and ds tunnel, youll know once you take it off. +1 on csb,

[Hallatauer]

Transmission mounts or the Center Support Bearing are likely culprits.