Jack the rear of the car up, remove the 4 bolts that hold the driveshaft to the rearend and drop it down, but leave the other end in the trasmission. grab the yoke (or where the 4 bolts were) and see if there is play....side to side, even make sure it doesn't wiggle. Make sure the pinion nut isn't loose.......or just take it back to the guy that did the rear and tell him it's noisy....It sounds like the gears aren't set up right.
02 yellow GT auto......SOLD.
Looking for another, stay tuned!