How long would a rebuilt transmission last if I had a good mechanic?

I have a 1986 Toyota Pick up and the transmission is about to blow. I dont want to spend a lot of money but I don't want to get rid of the truck either. If I have a really good mechanic, how long should I expect the rebuilt transmission to last?|||if done right it will last as long as a new one.|||as long as a new one|||Generally about 140,000 mi.and it also depends on proper maintanence.Rough driver may be less.|||If done right it will last a long time.|||There is no way to answer that question seriously it could honestly last 2hours or ten years even though the mechanic did everything perfectly. There's no guarantees just warranty's.