OK, I have a TH 400 trans, 406 chevy engine, 73 Nova rear all in a 37 Chevy. When I accelerate or decel from either first to second, or second to first there is a clank (like a double clanking) sound. It sounds like it is coming from the transmission or front u-joint area, but the car is short so is hard really to tell. Obviously I can run beside the car and listen from the outside. I have had the car on stands (actually still is) and I cannot find any thing. U-joints seem tight, I pulles the diff cover and all looked good in there. it only does it going from 1st to 2nd on the upshift or from 2nd to first on the downshift. Does not matter how hard or how easy the accel is.

Any ideas? Is there somethign in the trans that could be the issue, but that would allow the car to drive perfect other than that clank.

Brett