it sounds like your govorner is sticking in the tranny, or the valves are sticking. a good flush (done by a pro) may cure it, but you might need to partially dissasemble the tranny and repair the govonor/valve body. over full shouldn't make it stick in gear. also try adjusting the TV cable if yours has one. a chilton should tell you if it does, and if it is adjustbale and how. if you do a search i've written some on adjusting the TV cable. it might have slipped and is relativly closed.