Guys. Everyone needs to take a breath and calm down about the dealership. Since Mark is a friend. I called him. Here are the facts. The car was bought used from some third party. Neither Mark nor the owner knows the car's history so Mark said that he would carefully inspect the vehicle and discuss his observations with the owner. The car has a 3.73 rear end. It sings at 50 MPH. The wear on the rear tires is uneven and there is between 1/32 and 2/32s of an inch left before the wear bar indicates a need to change them. In other words about six percent left on the tires - not 60%. The tires are also as stiff as a board and are probably the original tires that came with the car. The floor pan is pushed up under both the driver's side and the passenger side of the car indicating some form of past problem. Since the wear is differnt on the tires side to side and the diff is singing at 50 MPH and the diff fluid looks like s**t, minimally a change of diff fluid seemed like a good idea. There is more to the story but I think those of you who jump in with negative criticism so quickly might consider checking the facts first.
So there are THREE sides to this one! Different perspective for sure...