I am about to buy a 1986 caddy deville in mint condition, it runs awesome. They said that it is because of the tranny it stalls up even the slightest hill, could it be? I don't know. Please help me out ASAP

sounds like it's starving for fuel.

yeah, i'd agree. if it shifts fine on a level surface, i can't see how that'd be the case. perhaps the tcc solenoid is sticking, so it loses power going up a hill and can't downshift.