Did it start after the new disks were fitted???
You have to clear all the rust and muck off the mating surfaces of the disks.
Not a flat spotted wheel where you have fallen into a pot hole. Know you said they have been swapped around but did you do fronts to back????
Have the wheels balanced on the car???
Have no idea really just things I would check to eliminate, before getting into the drive shafts, which I wouldnt know what end to look at!!!!
Best of luck with it, hope you solve the prob.
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