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!
Best truck I ever owned
Love my GMC. Owned a Chevy and this absolutely beats it hands down. Never had any issues. Inside is very comfortable and can't imagine driving anything else
Unreliable mechanical and technical nightmare!
First GMC, last GMC. Buyers, run in the other direction from the 2021 GMC Sierra 2500HD Denali, or live with daily, expensive regret! This is the worst and most unreliable vehicle I have ever purchased (new), and I have had many new and used. Steer clear of this year, make, and model! Expect mechanical failures, issues and annoyances you will never get resolved despite numerous trips for diagnostics and repairs, even if the issues are known and popularized. And expect to have your vehicle in the shop for weeks-months annually for unsuccessful diagnoses. And good luck with getting quality dealership service, even if taken out of state to give other locations a chance. This truck has persistent ac and defrost issues over 1500 rpm from day 1 with no resolution, makes desert summers and any winter driving miserable. Your only saving graces are keeping towels on hand to “defrost”, and cooled front seats for hot days - when they work! So expect to drive under the speed limit or without pushing the truck too much on inclines if you want to have ac/defrost conveniences. Multiple sensor failures/errors - too many to mention. Recurring blown fuses and issues with trailering system - as in several times per month - dealerships “see the messages but can’t find a problem. Recommendations made - keep boxes of fuses on hand at all times. Repeat issues with braking system, even after service bulletin repair - brakes are slow to respond and most embarrassing squeaking ever heard. Also receive constant messages that “new brake pads are found”, with info screen saying there is 0 front brake pad life. One of my other least faves is that the camera system that is played up with the extensive angles is useless for the views you need the most - Misaligned reverse camera - off center, negating use of the camera for hitching. “Split” in camera view that appeared after first service appt to resolve the recurring screen blackout makes using the camera for centering vehicle between parking lines impossible - as you never know if the top part of the screen is accurate or the bottom. Dealership response - “we compared to others, and most have these same issues”. What?! Advisors feel this acceptable, “within spec”?! Zoom in on the photos of this make/model for sale - you will see this in most of them. Shaky steering column during ENTIRETY of every drive and loud rubbing when reversing and turning wheel to back out of spot or do 3 point turn - acknowledged by techs yet they “can’t find the issue”. Ongoing shutter error codes and check engine light - even with a service bulletin, if the light turns off before your appt (which occurs consistently), you are out of luck for repair. Truck chirps when going over bumps which is also embarrassing in parking lots, and it squeaks when you exit the vehicle - yet more anomalies acknowledged by the technicians but root cause/s unable to be identified. And then there is the occasional loud gear grinding when moving to 1st gear, the more often struggle of the transmission into 2nd and 3rd, and the vehicle lurching when trying to maintain slow speed in these gears while towing. The DEF and even fuel level gauges - completely unreliable; have had multiple mishaps at night in the boonies due to this (must keep DEF on hand at all times!). I have 5 roadside assistance packages that I subscribe to; yet none of them will help get this vehicle to a shop when you are stranded more than 10-20 mi away from a GMC dealership. So expect to pay much and often for your per mile towing rate for truck breakdowns. I could literally go on and on about the MOST stressful purchase I have ever made. You will find 95%+ of your issues either “cannot be reproduced” during your service appointments, are “within spec”, “can’t be figured out”, or “due to something different than your last visit” - in other words, this is how the game is played to disqualify the vehicle as an official lemon for lemon law purposes.