Does your car have a roof rack?
I have had a Dana 60 rear axle with drums on my VW roof rack. A 1/2 ton frame should weigh about the same. And if you had a car with the roof racks spread out a good bit, like a station wagon or a suburban it should be sturdy enough.
Don't rent something if you don't need to.
Even if your car had a trailer hitch and a roof rack you could make a simple prop to go up from the hitch and support the rear end of the frame?
