hi. I have a 1996 Explorer where the transmission wont allow the vehicle to move more than 1" per second(for. or rev.). It has 175000 miles on it, so a rebuild is needed, but i prefer a used or recently rebuilt unit from web. Is this a common problem that may be externally fixed, or is a used/rebuilt unit my best chance(it cost me 2k so 1500=trans is too much, primarily back-up vehicle)? Thanks (auto trans r voodoo)