i didnt know about that gasket wikki. next time i take the tranny apart im definately getting one...

as for your shift, i think your assumption is right with one of the piston seals slipping. they are a HUGE pain to reinstall, and get the seals and everything to fit up and stay. once you do it a couple times though it gets easy lol.

if you need anything drop me a line on AIM, im always on there.