During rebuild, when installing the 2-3 (or the 1-2) clutch apply piston, it's a bugger trying to get the piston into the cylinder, and very easy to maul or turn the lip on the seal. Bad seal = poor/slow clutch engagement. Just a thought.
Last year I had the trans out again and took the direct drum apart and it had a rolled inner piston lip seal. I had that fixed, I don't have a piston compressor, at a trans shop and put it back together. It shifted better, but not like it should.
