I just got back with my dads truck on a 2000 mile trip through the rockies its a 2011 dmax with allison trans. 4x4 z71 ltz pulling a 12000 lbs+ gear fifth wheel. Trust me you'll love that truck. Its a monster. Does your truck have the exhaust brake? It worked great in the mountain passes.
Congrats on the new tractor too!
My truck does have the exhaust brake and even without towing anything I can tell it's going to be awesome. GM trucks have been good to me and I have no reason to believe this one wouldn't be a pleasure to own too. My last truck was a virtual twin to this but with the 6.0 gasser and it towed like a dream. I can only imagine how nice this will tow with all that extra power on tap.