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If locking up under load, it's probably not brakes and rear parts best inspected before further damaging whatever's wrong?
Has someone watched Pinion @ Shaft for movement while shifting from drive to reverse?
Have you ever had the car moving around under its own power or a roller since you got it?
I know you've listed parts here in the past but what cars/parts are you looking to unload now.
Keep rockin'!
~ Pete
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