**NAVIGATION/GPS**, UNROOF/MOONROOF**, *ONE OWNER**, nd DVD PLAYER. Duramax 6.6L V8 Turbodiesel, llison 1000 6-Speed Automatic, nd 4WD. Creampuff! This handsome 2011 GMC Sierra 3500HD is not going to disappoint. There you have it, hort and sweet! Whether you're sitting in the driver's seat or standing next to this 3500HD Denali, ou'll be impressed how quiet the turbocharged Duramax 6.6L V8 is. Sure, t's still a diesel, ut the normal noises are significantly muted at idle. The engine is also quiet at highway speeds, here it's effortlessly strolling along under 2000rpm. New Car Test Drive said, ..If you want the capability of a big pickup with the least sensation of driving a big pickup, he Sierra HD deserves consideration. In a world run amuck for ever-larger trailers and powerplants, t's a sensible alternative for anyone who needs to haul heavy material but doesn't want a Class IV or V truck to do it...