Bought the vehicle with 97,000 miles on it. within 10,000 miles had to replace injector number three. First winter all three heating element’s went out. Took it down to have it serviced and the tech found a leak coming from the transmission upon further inspection. The seal before the torque converter was already bad and leaking after that was replaced. We hooked up to a toy hauler and went on a trip halfway through the trip the truck Started a slight shaking. When we got back, went to the dealership and they said I had bent a rear axle. This was a bumper hitch toy hauler. And came in at under 10,000 pounds so tell me how a 2500 heavy duty truck is supposed to pull anything if the axles under that small of weight. Back up camera has gone out intermittently a few times as well. I highly recommend looking at a different truck if you’re looking for a three-quarter ton. Also don’t be fooled by the Allison sticker. It’s not a true Allison transmission and probably will never hold up to the standard that Allison is known for. I I definitely will be trading it in.

This thing has been a nightmare since we bought it. We purchased it used in 24 with 100k miles. A few months later it blew a head gasket and had to have a new engine put in. Since then it's been chasing down intermittent, random check engine codes and losing coolant to which we can't find the source of. The multipro tailgate is a pain and only works half the time. Sometimes the radio freezes. "Service steering column lock" message intermittently. Clunking shifting and hesitation around 55mph. It goes on and on. Between our own pocket book and the extended warranty, over $30,000 has been spent in repairs. Yes, you read that right, 30k. Biggest piece of garbage ever.

I love my 2021 GMC Denali 2500HD. I have gotten more complements on this truck than any other vehicle that I have owned. I get great highway fuel milage average 19-26mpg,which is great for a heavy duty truck!