Well this seems interesting to me... Since when do people put Lucas oil in automatic trannys? Or do they now have a special brand for automatics?
To me it doesn't sound like a tranny issue at all. I mean, in some strange way it could be a problem, but I bet its the motor. Give the whole thing a well rounded tune up. New plugs, wires, change oil and filter, change air filter, change tranny fluid and filter, (do not add anything else to it this time) change PCV valve, change fuel filter... Hmmm, thats all I can really think of right now off the top of my head real quick here.
But I would try all that before going and spending a ton of money on a new/used tranny.