i have a 10 speed RR behind an 8. 3 cummins. the only time i use all the gears is when i tow something real heavy,say 50,000lbs. the rest of the time i skip gears,trust me,it sounds cool to say you have a 10 speed,but your truck will be slow going through the gears,stick with a 5/6 speed,you will be happier.
Randy