With the exception of its sparkling optional 20” chrome wheels, the 2015 GMC Sierra 2500HD Denali takes on a more understated look and presentation than the jazzier cowboy western store top trims of other brands. It has body color bumpers and just enough chrome to say its top of the line.
While it’s all dressed up, functional hot-buttons here are the integrated steps in the rear bumper which make it easier to get up into the box. The Denali also comes standard with the tubular side steps, front tow hooks and fog lamps.
There are also power folding heated mirrors which are likely a pretty good idea if you are parking in tight quarters. And being the HD class pickup it is with four-wheel drive it also has a pretty high riding profile as you would expect with plenty of ground clearance.
Moving inside, the Denali continues the understated approach to high-end pickup truck luxury. You wont find garish colors and belt buckles on the console here, instead a business like tone that says top of the line a bit more softly.
The dash is wrapped in soft touch materials with contrast stitching, genuine aluminum trims and just enough wood-grain to warm up the look. Our tester had a monotone jet black interior but you can also option a two-tone treatment with tan hides.
Those leather seats are heated and cooled up front with the driver getting memory settings. In the rear the heated leather bench can fold upward with a 60/40 split which allows for additional cargo storage of tall items.
The cockpit is well laid out with important controls located within easy reach such as the integrated trailer brake controller. The instrument cluster has two traditional dials and a customizable center screen with virtual gauges.
You will find the tilt and telescoping steering wheel is heated in addition to having controls for most audio, cruise control and driver menu functions. Huge storage options are found in the center console which also has 110V outlets and all manner of connectivity options including USB.
Front and center is the 8” touchscreen top-end Bose audio and navigation system with Intellilink. The menus are very easy to use and navigate even while on the go. The system also boasts a 4G LTE WiFi connection which can accommodate up to seven devices within 50 feet of the truck. Nice.
With the optioned driving aids, there is GM’s Safety Alert Seat which gives you a friendly vibration when you need to be told you are straying from your lane or coming up on something too close. It has left and right side alerts depending on where your lack of attention is.
Under the hood is the optional 6.6 liter Duramax V8 turbo-diesel. While not the most powerful on the market, it is very close with 397 horsepower and 765 lb-ft of torque. That power is delivered to the ground through an ultra heavy duty Allison six-speed automatic transmission.
Weighing it at nearly 7,400 lbs, all that power doesn’t translate to a high-performance driving experience as it relates to power. With the weight of two Camaro’s, the truck still has pep, but takes some prodding to get moving.
Towing is really much of what optioning this engine is all about. With its prodigious torque it can tow up to 17,100 lbs as ours is configured and has a maximum payload of 2,793 lbs. That means for instance it could tow a trailer loaded with two trucks just like it.
On our washboard back-road, the Sierra exhibited moderate shudder and shake as is to be expected in a pickup truck. As ours was optioned with the off-road suspension and Rancho shocks, it was stiff riding and had little give for the rougher stuff, which in practical terms is good. It’s not meant to ride like a crossover SUV.
Rolling at a good clip I was able to experience the interaction of the Stabilitrak stability control system. Going around these gravel corners the rear of the truck wants to swing out, but as soon as I felt that feeling, the system stepped in gracefully and predictably keeping it in line.
On the highway the ride is of course smooth and solid, with a firm planted feel. With all the sound deadening afforded for the diesel engine it is quiet as can be in here at speed. This translates to a comfortable place to spend many miles.
Living with the Sierra 2500HD is surprisingly easy. Even though it is a very large and heavy vehicle, its four-wheel disc brakes are strong enough to keep it manageable around town in stop and go traffic.
The suspension and steering are nimble in a way that makes it no more difficult to handle than most sport utility vehicles and the standard rear-view camera makes parking lot gymnastics a snap.
We achieved 17 mpg during our week with the 2015 GMC Sierra 2500HD Duramax. This was a combination of about 50% city and 50% highway. Our best highway mpg was 22.5 which is very good for a vehicle this large and heavy.
Overall, the truck earned a four out of five star rating for our week.