I have a 1994 LT1 six speed vette. The clutch was slipping in the higher gears and higher rpms. I bought a single mass clutch and flywheel conversion kit from Eklers. This included the throw out bearing. While I was gonna be in there anyways a picked up a rear main seal too. Had the new parts installed and discovered a bad shake /shudder when slowly releasing the clutch in first gear. and reverse. It shifts through the gears just fine, it just does it when starting from a stopped position. Took it apart again. Noted uneven wear marks of the flywheel face. Brought it to a friend of mine who has a machine shop. We dial indicated the flywheel and discovered it was out by 5.5 thousands. We also indicated the hub but it was very close about .500 of inch out. Put it the lath and resurfaced it to near perfect. Put it all back together. Cleaned the hell out of it with brake cleaner and bolted up the trans. Took it out for a test drive and it is still doing it. Any ideas would be greatly appreciated.

 

I have this shuddering issue in 1st and reverse as well. Anybody know what may be the problem?

 

Hello? Anyone with any answers?

 

You can check the clutch facing to see if it has any contaminants on it.

 

Clutch chatter is nearly always caused by a weak spring in the pressure plate. Very common problem with rebuilt pressure plates, and cheap made in China equipment.
Typically gets worse as it gets hotter.