I traded in my 2004 2500HD with 6.0 and 4.10 for a 2015 3500HD with 6.0 and 4.10. Like said above, the RPMs will get up there on the hills, but with the cab of the 2015, you can barely hear the engine and transmission. My 2004 was much louder. I pulled 11,000# with both trucks and had no problems. The reason I own the 3500 is for towing and if I wasn't happy towing with my 2004, I certainly wouldn't have bought the same thing eleven years later. Everybody tries to tell you, you can't do it without a diesel, but that's not true. The Chevrolet 6.0 is a great motor.
Bruce