Tim,

My own suggestions, having rebuilt my own transmission 3 times before 
finding the actual problem, is to check the rings on the oil pump, see 
if one is broken, which can indicate a problem with the end play 
adjustment.  Also check for wear on the backing plate in the oil pump, 
low pressure can cause all sorts of shifting wierdness.  I found the 
linings supplied in the rebuild kit were thinner than the originals, 
so I kept the old ones.

Dennis is right about the torque converter... crud can cake on inside 
it that's impossible to get out for the DIYer, but will slowly release 
back into circulation.  I would look into getting it flushed out at a 
tranny shop, if I had it to do over again.  It would have cost me $15, 
they have special equipment to flush it right.  It's VERY difficult to 
find a rebuilt TC for a late model van.  The first one I brought home, 
having traded my old one, wouldn't clear the housing.  The next one 
fit, but the letter stamped on it indicated it was from a mid 80's 
vehicle.  While it fit and continues to function, I think there is 
more slip in it than my original, the engine turns about 200rpm faster 
on the highway.

Dan Fuller
'90 Carat