I'm having the same problems and it ended up being the t stat.

 

hey man what are the tranny temps at? do you have your converter locking up any while driving? i would check the fans. bypass the harness and try it. where is the tranny cooler mounted. take off the hose from the coolant bottle to the top of the rad and drill it out. flush the system. check for sludge. this will be a start. if you want bring it by and we can test it out dude.