2020 GMC Sierra 2500HD

By June 15, 2020

The 2020 GMC Sierra 2500 Series HD is a testament to the brand’s experience and expertise in the realm of heavy-duty full-size trucks. This Sierra HD is bigger, brawnier, and more technologically advanced than any preceding GMC truck.

The new Sierra HD has grown in size and interior dimensions, and the styling—for the first time distinctive from that of the light-duty Sierra—further exemplifies the sheer mass of the truck.

Technology and active-safety features were a focus on the new Sierra HD, and available equipment includes blind-spot monitors, lane-departure warnings, and automatic emergency braking. Also available is a rearview camera mirror and a multi-angle backup camera that allows for easier reversing maneuvers with a trailer.

The raft of available safety equipment and the large size of the Sierra HD should put to bed any concerns about crashworthiness. Still, shoppers should be aware that official crash-test data is not available for trucks of this class, as they do not need to be federally tested.

The same goes for gas mileage. The EPA is not obligated to rate heavy-duty trucks for fuel efficiency, as their size and weight exempt them from testing. Suffice to say the Sierra HD is not exactly a fuel miser.

A 6.6-liter gas V-8 enters the Sierra HD lineup this year. This new engine makes 401 horsepower and 464 lb-ft of torque. A 6-speed automatic sends that power to the ground.

The 6.6-liter Duramax diesel V-8 shares the same displacement as the gas engine but turns out 445 horsepower and 910 lb-ft of torque. It comes into 2020 unchanged, but its partner in crime is now a 10-speed automatic made by Allison.

Maximum towing capacity is now over 35,000 pounds with a fifth wheel, up significantly from last year. With conventional hitch, the Sierra HD can pull 20,000 pounds.

Model Lineup

All prices reflect rear-wheel-drive models and the cheapest bed and cab configuration. All prices also include any applicable destination charges.

The Sierra HD trim hierarchy doesn’t stray far from how the standard Sierra is broken out. That means the base HD is known simply as the Sierra, priced at $37,395 before any options. That money buys a spartan truck, with a 7.0-inch touchscreen, Apple CarPlay and Android Auto capability, LED lights, and single-zone climate control among its few notable features. A vinyl bench seat and vinyl floors are standard, as are manual windows and locks.

Stepping up to the $41,995 SLE adds remote keyless entry, power windows and locks, cloth upholstery, a leather-wrapped steering wheel, and cruise control.

The $52,595 SLT trends towards luxury with an 8.0-inch touchscreen using an upgraded infotainment system, heated front seats with 10-way power adjustment, leather upholstery, a heated steering wheel, and remote start.

For $59,895, buyers can get the off-road oriented AT4. This model is exclusively offered with Crew Cab and four-wheel drive, and includes special suspension modifications such as long-travel shocks, all-terrain tires, and an off-road mode. Amenities include heated and cooled front bucket seats, a rear-seat armrest with console, and perforated leather upholstery.

The $65,895 is the fanciest Sierra HD in town. It gets Bose audio, 20-inch wheels, genuine wood trim, heated outboard rear seats, and numerous active safety features like lane-departure warnings and automatic emergency braking.


For the first time ever, the GMC Sierra HD shares almost no styling cues with the related Chevrolet Silverado HD. The taillights and general rear-end motif remain similar between the two, but otherwise the Sierra HD enjoys styling that is all its own.

That’s to the Sierra’s benefit, as the GMC stylists have penned a more attractive look than what came out of the Chevrolet studio. The front end of the GMC is purposeful and brazen in a way truck buyers love; it means business and wants the world to know it. A big, squared-off chrome grill and angular C-shaped LEDs amplify the attitude.

The Denali and AT4 both take the Sierra HD’s style one step further. The Denali adds traditional luxury cues like heapings of chrome trim, a chrome-mesh grille, and big chrome wheels. The AT4 skews off-road, with a blackened grille, bumper-mounted recovery hooks, and black 17-inch wheels with brushed chrome edging. Both packages are distinctive and attractive.


The Sierra HD has a finely crafted interior, especially low-trim models. Move higher up the food chain and the busy design and average materials won’t wow shoppers the way a Ram 2500 Laramie Limited or F-250 Platinum will.

Plenty of storage is available throughout the interior, with lots of nooks and cubbies to stash things in. The front console will swallow a laptop with ease.

The base vinyl seats won’t be found in any living rooms, but the leather bucket seats are comfortable, supportive, and generously sized. The 43 inches of front leg room should be ample for even the tallest drivers and passengers.

If they somehow don’t fit up front, send them to the rear, where the 45 inches of rear leg room on Crew Cab models is touted by GMC as class-leading. Head room and shoulder room are equally expansive, and there’s no shortage of space for as many as six passengers. Denali models even come standard with rear outboard heated seats for true pampering.

Cargo capacity is not an issue for the Sierra HD, which can tow up to 35,500 pounds and haul up to 7,450 pounds in its bed. Every trim gets a dozen tie-downs, each with a 500-pound rating, and LED bed lighting is available. Nifty bumper steps make it easy to access the bed, and the new six-way tailgate that is standard on the higher trims includes a bed step to easily walk right up into the cargo area.

Base models use a 7.0-inch touchscreen, but the 8.0-inch unit that is standard on SLT models and up is fast and intuitive. It won’t match the Ram’s 12-inch screen for wow factor, but it handles infotainment duties without any of the pain some systems inflict on their users.

Driving Impressions

The Sierra HD drives as big as it looks. From behind the wheel, the sheer mass of this truck might intimidate those who aren’t used to piloting full-size pickups. A big turning radius, nearly 22 feet of total length in its longest trim, and a high, commanding ride height give the Sierra HD the feel of a big rig. Seasoned truck buyers will likely love it.

All that size doesn’t spell good things for handling. The Sierra HD is best nursed through corners rather than hustled. It is happiest at the hands of an unhurried driver who’s chugging along the interstate.

Handling is an afterthought with these trucks, however; the real reason anyone buys one is for capability. In that, the Sierra HD delivers. The new 6.6-liter V-8 is strong and powerful, and it tows and hauls enough weight that there’s no reason to spend $10,000 for the diesel option unless you’re regularly pulling some serious tonnage.

The Duramax 6.6-liter turbodiesel is nonetheless a popular upgrade among buyers, and its savory 910 lb-ft of torque is likely a big reason why. It now mates to a 10-speed automatic transmission, which is the first of its kind in the HD truck segment. Most HD pickups soldier on with familiar and proven 6-speed automatics. The additional gears should help with gas mileage on the highway, though the EPA doesn’t release official fuel efficiency figures for these vehicles.

A plethora of available tech can make the task of parking or trailering with the Sierra HD a far less nerve-racking affair than it might otherwise be. Our favorite feature is the multi-angle camera that has the ability to essentially render any trailer invisible. It is able to look through and past the trailer to see the road behind as well as the blind spots to the sides of the trailer. It makes backing up to a trailer as well as towing with one easier than ever, even for the novice.

Final Word

The 2020 GMC Sierra 2500 HD is an excellent option in a very competitive segment. Standout powertrains, nifty features, and an attractive new design all should help the Sierra HD continue to woo buyers who need the utmost in capability. We’d get an SLT for its luxury touches but relatively reasonable price.


—by Anthony Sophinos, with driving impressions from The Car Connection

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