I have an '86 GT with 140,000 miles. Today, the rear end started making a scrubbing sound similiar
to having too large tires. I recently had the rear end lubricant changed including a friction modifier.
Could my clutches be worn out ? The car has not been abused.
An old trick with the 8 and 9 inch traction lock rears was to drive in a tight figuare 8 for a few laps, maybe half dozen. Not fast, just steady laps. Did not not always clean up the noise, worth a try.
It could also be a bearing, hope fore the best.
Or could be a prius stuck in your wheel well.
Sorry, couldn't resist.