I have owned this car since it was new, I bought in April of 2010. It suited my needs to a tee. However I have always complained about the clunkiness of the driveline. When shifting from park to drive it would clunk, not real loud but enough to call attention to itself. I would also notice some clunking when it automatically downshifted. Not all the time but on occasion. This car has a sport mode transmission that works like a busted fanny, I never used it because it is stupid. In any case I repeatedly complained to the dealer about the clunking noises that he, of course, could not identify or find. He kept saying that the differentials needed servicing so like a fool I fell for it and had them serviced. To no avail. Finally I figured that this was normal in the All wheel drive systems of Cadillacs, being a half-assed system. Well on said date I was traveling west bound on I74 in Indiana SW of Indianapolis when boom, I lose all power to the wheels. I was doing about 70, the speed limit. Fortunately the traffic was light and I managed to pull to the shoulder. Well it turns out that the center differential gear had stripped. I surmise that this was never a good part in this car and should have been replaced when I first complained about it. Now that the car is just out of warranty I had to shell out 3 grand to have it fixed. Now that its fixed the car has never run better, it apparently runs like it should have. BTW the center differential gear is a sealed system requiring no service. Warning to people interested in Cadillac AWD systems, run away from them as fast as you can. If you are pent on an AWD car look at Audi or Subaru.