Originally Posted by DPS
We've been seeing this problem lately on LGT's and late model WRX (push style clutches). The noise is even worse on LGT's that install the WRX flywheel/pressure plate combo. The noise is coming from the clutch fork vibrating against the slave cylinder pin. It can easily be misdiagnosed as a bad throw out bearing. The trick is to drill a small hole on the clutch fork and install a spring to give the clutch fork a slight pressure against the slave cylinder pin (similar to pull style clutches).
Have you been seeing this on stock vehicles as well? I don't hear the noise very often though, mine is the heavy vibration in the clutch pedal, I heard the squeaking noise noise only that one time when the problem really ticked up a while back.