I purchased a '05 GTO 11 months ago and from day 1 have had problems. At 1500 miles I had it in for it's first service and asked them to check a noise I heard from the rear end. No satisfaction. They deglazed rotors to no avail. At 5000 miles same noise, they resurfaced rotors...no bueno. At 5700 miles they told me it was normal brake noise..HA!!HA!!! Finally took it to my own mechanic and opened a file with Pontiac. My mechanic diagnosed it in 45minutes. Pinion gear going out. Pontiac told me to take it to another dealer, which I did, and they agreed it needed to be rebuilt. I told them I wanted a new differential AND new rotors. At about the same time they came out with a TSB telling the dealers not to rebuild but to replace the differentials on all GTO's that have pinion gear problems. 26 days out of service for this problem and 4 times in the shop and the problem will finally be fixed this Monday when a new shipment of dana rear differentials comes in from Australia. Too many times in the shop for me and I'm now trying to get GM to buy the car back from me with the help of a lawyer and the "lemon law" here in CA. Anyone else having the same problem? The wait for 30 days for the new differential to come in tells me they have a MAJOR problem with these.