I am converting a LT1 T56 to fit the LS1 engine. The tag reads 1386-009 so I believe its a 94-95.I bought the conversion kit from Rockland gear. I had the transmission vertical and measured for endplay, shimmed down to 0.02" and when I put it horizontal on my bench, then input shaft now seems to hit a bind once per revolution, at the exact same spot. When it hits the bind, it seems like the input shaft actually moves upwards to get past it. I have taken the midplate off more times than I can count, shimmed multiple different times trying to go from nothing to too tight but its always still there. I went back to the LT1 input shaft and midplate and when that is installed, it spins perfectly fine.

Any thoughts on what else I can look for? I have attached a few pictures and videos. Is the snap ring behind the blocker ring supposed to look like that? As well as the small chunk out of the bevel behind the input shaft? (looks machined so I figure it is, but just want to make sure).
Thanks for any insight, new to T56 world and pulling my hair out.

 

Here is a video of me turning the input shaft at a high rate, with a good clunk every revolution.

 

Here is a video I took when I had no shims on the input shaft. It seems when putting pressure to the lower left (if looking at the input shaft from the rear of the engine), it clunks the worst. When putting pressure on the upper right, it seems to spin freely. This seems to change when I shim it, as putting pressure in the upper right doesn't seem to help as much.

 

Check the input shaft for a knick in the tooth near the top. For whatever reason, these input shafts are very touchy to the smallest imperfection or small dings. 99% of the time, touching it up with a small file or angle grinder with a 80 grit pad on it will take care of the issue. Sometimes, the knick or ding is so small, it's hard to even catch visually. I would take a mental note of where the bind is when rotating it, make a mark on the shaft and see if you can reference it once you remove the input shaft to inspect it.

 

Thanks AMP - you were correct. There was a pretty sizable knick in the input shaft, as well it look like the next tooth over wasn't machined as much as the others. I have touched it up a bit and it's better but still not gone. I am going to get some gear marking compound today and see if I can tell where a high spot is.

I have also sent you a PM, just in case my method doesn't fix it.

 

Got the new input shaft in last night, turns like butter. Glad it wasn't something that I had screwed up. Thanks for your quick diagnostics AMP-D.

 

Glad it worked out.