This is the small, common, pilot bushing in the back of the crankshaft. It is important to make sure there is minimum clearance here, if sloppy, the 1st motion shaft will wobble thus causing the trans. front cover scrolls to wear. It sure helps to use our front cover with a seal installed to eliminate fluid leakage. See part #RCT-429.
This bushings size is .624 OD.
Pilot Bushing - Small - "A" series