if you don't mind I am going to tag along on this thread. I have a 2002 focus that I just bought. my tranny works it just is a little rough shifting on occassion. I believe we have the same tranny a 4F27E. I plan on changing my filter and then pumping out the rest of the fluid and replacing it........it sounds like you have a good mechanical grasp so excuse me for asking the obvious question..........Did you check the tranny fluid?
2002 Focus ZX3, Zetec 2.0, Auto, 106k. RECENT WORK= 5w-20 , Coil, T-stat housing and flush, Autolite APP5364, new steering Rack, full tuneup, tranny filter swap and fluid exchange. SOLD(Grandma gave my kid her Camry. I really liked the zx3 )