Am getting ready to purchase a new truck. I at one time had a 2003 Chevrolet 2500HD with the 6.0, I always felt like the motor had enough power but the 4-speed transmission just couldn't keep up. On the new HD's they have not only upped the power in the 6.0 engine but are now also putting the 6-speed transmission in them. Does anybody have any experience with this transmission? Any MPG figures? I don't think I can justify a diesel when you consider the extra money up front PLUS the extra money at the pump. Any advice would be appreciated.