Car in question is Z28Roxy's 95 with a T56 swap. It's make this horrible rattling sound, which seems to be coming from the trans or bellhousing area, in between shifts mostly. It's like:

Accelerate in first gear
push clutch in
WHIRRRRRRRRRRRRRRRRRRR
shift into second
let clutch out
sound goes away

It also is lightly audible in gear but nowhere near as loud. Also what's weird is that it seems to quiet down a bit after driving for a couple minutes.

edit: Here's a youtube vid of it.. I know the sound quality is terrible but you can still hear it:

http://www.youtube.com/watch?v=u3a9gy91O2Q

My only guesses so far are possible loose pressure plate bolts, bad throw out bearing, or loose clutch fork.

Anyone have any ideas? We might be able to make a small video of it that shows the sound.

 

I would suggest the throw out bearing.

 

I cant check out the video example here at work, but I had a similar issue and it turned out to be a starter bolt and it ended up backing out and was rattlin a storm up, it was right after I had somebody install a clutch

 

I'm also having a problem like this all of a sudden... I cant wait to take my car apart again... all of a sudden I came out to drive one day and it was stuck in first gear, now when I drive it rattles between gears and when stopped. If I give it gas between shifts its fine though.. My throwout bearing is shot perhaps?

The clutch was replaced with a spec 2 before I bought the car, no idea if everything else was properly changed though...