I have a T-5 box out of an 85 or 86 v8 (came from a 91 Iroc, but the tag says otherwise) camaro in my sonoma pickup, which I have just finished installing. I'm using a Howe racing hydraulic throwout bearing setup and a 11" clutch. My problem is, after filling the tranny (mobil 1 synthetic) I'm getting a squealing noise, sounds like a bad bearing, coming from the bell housing. Does not change with the truck in or out of gear, under load or not, goes away above ~2500 rpm and gets quieter, but doesn't go away, when the clutch is depressed. Anyone heard anything like this before?

 

If it does it when the clutch is pushed in, the car is in gear, and sitting still, then it's not the transmission.

Sounds like something having to do with the throwout bearing.