The ride is harsh empty (but not like a F450 F550). The suspension is great with a load. The gas engine tows well - I pull horses, boats and campers. The fuel economy is 13-14 empty (highway) and 6-8 towing any trailer (2000-8000 lbs)
Update - after 38000 miles including over 15,000 towing heavy trailers I give this truck a great rating. It loves its fuel - but it is a reliable workhorse. Never a complaint and a flawless service record! Not a single issue.
First of all Edmunds doesn't give the Duramax / Allison option to review. That is what mine is so it might not compare to other reviewers. The some of previous reviewers must have been driving a completely different truck then I was. Some of those reviews just didn't make sense to me. This is an awesome truck. It's more "luxury car" like then any truck I've ever driven. My wife enjoys driving it because she has great visibility and it is so easy to handle for the "beast" that it is. It easily handles my 37 ', 10,000 lb bumper hitch travel trailer with a 900 lb Harley loaded into the truck bed. You actually don't even know all that load is back there.
I have a 2015 gmc 3500 dually with the durmax. I also put 24 inch 18 wheel style wheels with larger tires. My truck rides great and i had as much as 21 mpg on the hwy. I average about 15mpg but i do a lot of stop and go and sitting in Atlanta traffic. I have a 26 foot trailer and when i pull it it doesnt even feel any different. I had a ford f350 prior and i had nothing but issues. I also have new a ls460 but i rather drive my truck.
Bought this truck brand new. Needed a dually for towing. Thought I couldn't go wrong with a new Denali diesel. Was I wrong. Digital steering assist whines in the steering column when at idle. Ridiculous for a $70k truck. I also have cabin noise issues. I can hear the ticking of exhaust coming from dash area on driver side. Not well insulated for outside noises. And just last week noticed I have about 2 inches of play in the steering wheel. Hard to control at highway speeds. Gm has been terrible to deal with. They say everything is normal for this truck. Completely unexceptable. Traded my Ford F-350 for this.....big mistake. I am pursuing lemon law on this truck. Has been in dealer 3 times for same issue. Going in again to see if they can fix. Gm doesn't have a fix therefore it's normal. That's not gonna fly.
*Just to update. Took my truck in again for issues listed above. As expected GM has no fix for problems. They agreed the digital assisted steering is noisy but they don't know how to fix so they chalked it up to a normal characteristic of the truck. Really bad service. I'll be going back to a Ford soon. Never had an issue with my F350's.
Tranny kicks after coming to a complete stop,dealer says its gas slushing in tank. B.S Towing a load you get a bad viration that you feel on gas petal .not confortable driving over 60 mph to much vibration. To much electronics freezes radio once in while. When you have weight in bed approx 1000lb lifts front end it make your front end rattle.dealer said that was normal...every problem is normal.