I would look at your wheel alignment angle. If it is leaning too much the rear trailing arm may be rusted. It is a common problem and the cure is to replace the trailing arm. If it is needed a used arm can be sourced from a southern or western car and the installation is anywhere from 150 to 300 labor.

Good luck!

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.