With as many miles as the car has on it -- you would most likely be looking at a transmission rebuild.
Agreed. My old 94 Camry V6 had the same issue and it turned out that the transmission was shot. I had it replaced, but a few months later it started to shift hard from 3rd to 4th. So, I wouldn't say that a trans rebuild is not an option. My point here is just think twice before buying someone's problem, especially if this problem is expensive and difficult to fix.