Need help identifying a clutch noise

[macipusy]

The car is a 91 SS modified with 215K and 5 smt

This noise originated while my care was being tuned on the dyno...after the last run was taken. A loud metallic clunking coming from the bell housing area...sounds kind of like slapping metal which is RPM dependent and usually going away above 4K.
This noise usually gets louder when I press the clutch in.
While in gear there is no noise.

Could this be a throw out bearing going out?

[Legacy777]

Could be a throw out bearing or something with the clutch fork....it'd be kind of hard to say for sure without opening it up.

It could also be something with the pressure plate too.....just a thought.

[log1call]

Strange the noise goes away above four grand. I don't like the sound of that. Are you sure it's not a motor noise? Sounds like time to pull the motor out anyway.

Try leaving your foot right off the clutch and listen to it, then rest your foot lightly on the pedal just enough to start to compress the clutch and have a listen, then push it right in and have a listen.

If we compare all of those situations and the fact it is quiet in gear, (and I am presuming stationary?), then we might be able to pin-point the broken bit.... maybe!

[macipusy]

Its definitelly not in the motor....we listened with a stethoscope.

The noise changes when the clutch is being pressed and in Neutral...even with very slight pressure on the pedal.

I've been driving it today and it is quiet...until I get on it and the noise reappears.

[log1call]

Mmmm dunno. Sounds like time to have a look in there though.

[entirelyturbo]

It sounds like the throwout bearing came loose off the fork, and is basically spinning freely on the tranny snout.

When that happens, the little arms on either side of the throwout bearing that attach to the clips that hold it to the fork... those hit the fork as the bearing in its entirety spins around.

Not sure why it goes away after 4K rpm though.

At this point, I'd say just pull the motor. If that's what you see in the bellhousing, then it's right there for you to fix. If it's not and it's in the engine, then you're already a step in the right direction.

[macipusy]

When the noise goes away at 4K it seems that at that rotation that frequwncy of the sound dissapates.

It actually has not been making any noise in the last 2 days...i've been driving nice. Today I got on it in 1st and 2nd and still no noise...strange but good for now

I was thinking of pulling the tranny out since I have never done it and wanted to learn.

If the noise comes back I will tear it apart and see what the problem is.