So I've thought about this issue a lot lately lol as I had my GT3076R grenade itself (waiting on parts).
Here's what I have:
- Makes the noise slightly in neutral (clutch pedal out) and in gear (clutch pedal in) with the car stationary.
- Makes the noise BADLY under load (driving or rear wheels in the air with ebrake dragging)
My thoughts on causes are now only the following:
- Transmission is shifting hitting the body under load.
(I really doubt it's this, as the shifter barely moves and I have clearanced the shit out of the tunnel, ensuring there's at minimum half an inch. I've also tested this by moving the transmission down another inch on its mounts, still makes the noise.)
- Resonance in the z33 transmission.
I think it's resonance. I'm using the S-chassis mount on the transmission with a crossmember I fabricated. If you look at the oem nissan mount it's a completely different design. It's also secured to the crossmember by a bolt nissan itself calls a "damper bolt". Nissan also uses a dual mass flywheel to smooth vibrations as well. I'm thinking this transmission is just super noisy by design.
Solution? I don't really have one, but I'm gonna build a new crossmember that uses nissan's mount system over the winter, but until the snow flies I'm just gonna drive it.