When I first disassembled my RAM 500 I found the flat washer behind the compressor nut was a very loose fit on the inside dia. It was loose enough that it was detected during the balancing procedure. I replaced it with a washer that i reamed to the exact O.D. of the shaft.

You probably have a different problem but check the washer too.

I used the WREN 54 balancing procedure in the kit instructions. I touched up the balance of the compressor a little bit and my engine is now smoother than from the factory.

Sid Gates