probably the harness to the E.C.M. that tells the damn thing when to shift. I had to replace the bunk where the wires go into the 4L80E on the motor home. my tranny fluid was running out through the wires. might want to check that out.

I know a lot about a lot of things BUT I still have a lot to learn.
Life is what you make of it. So, why not make a working machine to make it easier.