2021 GMC Sierra 2500HD

GMC has been building heavy-duty pickups since 1914, but the name Sierra 2500 was introduced in 1988 and given the HD (Heavy Duty) label in 2001. It is mechanically identical to Chevrolet’s Silverado 2500 HD, differing only in styling, interior trim levels and maximum payload (the Chevrolet’s is 205 pounds higher).

The Ford F-Series dominates the full-size pickup landscape, but neither Ford nor Ram break out their heavy-duty truck sales statistics from their half-ton (1500) models. Chevrolet and GMC do, however, and it’s safe to say that heavy duty trucks, meaning three-quarter ton 2500-labeled models and 1-ton 3500s, make up about a quarter of the pickup market. 

Buyers in this class have five choices: Ford’s F-250 Super Duty, Chevrolet’s Silverado 2500 HD, the RAM 2500, GMC’s Sierra 2500 HD and Nissan’s Titan XD.  Customers demand towing capability, passing power, long range between highway fill-ups, ground clearance, interior comfort and exterior styling that advertises size and brawn. The GMC Sierra 2500 HD, all-new in 2020, delivers on most of that, with the interior being its weakest point.

The Sierra 2500 HD starts out at $40,695 including destination fees, roughly mid-pack against the competition. That’s a basic work truck with a single cab, seating for three and painted steel wheels. Single-cab customers can only buy a work truck or SLE model, all other 2500 HDs are Double or Crew cab models. Double cab models have a choice of 6.8 or 8.2-foot beds in base, SLE or SLT models. Crew cabs get both of those beds, but all five trims (base, SLE, SLT, AT4 and the top-dog Denali).

That last model begins at $67,690, within a few hundred dollars of most of the other makes’ top-line models, but it can get very expensive when you start ticking option boxes. For example, the Denali Ultimate Package, which adds a rear camera mirror, a head-up display and a power sunroof, is an extra $2,270. Wheel upgrades run up to $2,995. The one we tested stickered at $78,755.

In between the extremes are SLE ($48,895), which adds rear air vents, remote keyless entry and the MultiPro tailgate. It also unlocks options like an HD rearview camera, a two-speed transfer case and many convenience packages. The SLT ($57,895), which adds an HD rear vision camera, a two-speed transfer case and digital variable steering assist. 

Above that is the off-road themed AT4 ($60,795), which adds a ProGrade trailering system and an off-road package as well as making some extra-cost options available that simply aren’t available on lower trims. AT4s also get mild styling tweaks including blackout trim and red tow hooks. This is truck for work, but the AT4 is dressed for play too.

There are two available powerplants, the standard 6.6-liter gasoline V8, which offers 401 horsepower and 464 pound-feet of torque, and the optional 6.6-liter turbodiesel V8 we sampled. The diesel does not come cheap, up to nearly $11,000 on some models when ordered with integrated power take off (for accessory devices common on work trucks), but it does pack 445 horsepower and a trailer-smiting 910 pound-feet of torque.

Good acceleration, a smooth-shifting 10-speed automatic common to both engines, a firm yet supple ride and relatively quick steering make driving in city traffic less of a chore than it can be in some other plus-size vehicles. On the open highway, the GMC is an effortless cruiser unladen, and can lug up to 14,500 pounds with the gas V8 and 18,500 with the diesel. Both numbers are solidly competitive. The extra-large mirrors and cameras on the top-of-the-line Denali 4WD Crew Cab we drove helped navigate tight spots.  

In just over 100 miles of combined city street, urban freeway and mountain backroad driving, we saw actual mileage of 14.5 mpg combined. The EPA doesn’t rate trucks like this, but what data we have suggests the GMC, and its Chevrolet sister, return slightly below average MPG for the class.

Where the GMC shines is in towing assist systems. The optional ProGrade Trailering System (standard on SLT, AT4 and Denali) includes an in-vehicle app with pre-departure checklists, trailer light testing, customizable trailer profiles, trailer tire pressure monitoring and a theft alert. Also available is a camera system with 15 different views as well as a jack-knife alert and a trailer length indicator. It requires some dealer-added accessories but is the best of these systems on the market.

The GMC Sierra 2500 HD Crew Cab’s standard bed has a maximum payload of 3,760 pounds. Though mysteriously 205 pounds less than its Silverado 2500HD cousin, that’s still better than most competing crew cabs. Double and regular cab models encounter more robust rivals from Ford and Ram, however.

At the top trim level for all the manufacturers, the customer gets a crew cab truck with features and amenities once found only in luxury cars. Ford and RAM have leapfrogged both GM on truck interiors, with high-def digital gauge clusters and expansive infotainment screens, as well as an abundance of soft-touch materials. The pricey Denali doesn’t feel as rich or as modern as the top Ford and Ram models. 

Inside the crew cab, GMC Sierra 2500 HD is the clear winner (a tie with the Chevrolet) in front seat space, with at least two inches more head room and fractionally more legroom than Ford, Ram or Nissan. Rear seat headroom for all five is within a fraction of an inch. These are big trucks inside and out.

The Sierra’s Infotainment systems are also a moving target within trim lines. The base work truck has an AM-FM radio and a couple of USB ports. SLE models can get an eight-inch touchscreen as an extra-cost option, but only as part of a package, starting at $2,330. On the SLT and above, the eight-inch screen is standard, though certain options are again costly. Navigation is standard on the Denali but part of a $4,600 package on the SLT and $2,075 on the AT4. GM’s infotainment setup is user-friendly and easy, at least.

Safety systems are available on all the trim levels, but at extra cost. On the base model, two packages—the $890 Driver Alert Package I (front and rear park assist, lane change alert with side blind zone alert, rear cross-traffic alert, and perimeter lighting) and the $615 Safety Confidence Package (forward collision alert, automatic emergency braking, front pedestrian braking) have to be purchased to get an incomplete suite of safety features. Note, that’s regular cruise control. The adaptive kind isn’t available.

In SLE and SLT trims, the $890 Driver Alert Package I is the same as on the base model, but there’s also the $595 Driver Alert Package II, which includes lane departure warnings, forward automatic emergency braking and collision alert, a following distance indicator and a safety alert seat with haptic feedback. Those same packages are available on AT4 models. 

Every one of those extra-cost safety systems is standard on the top-of-the-line Denali. It’s worth noting that many of the 2500 HD’s competitors also charge for this gear, but it seems like more could be included on a $70,000 vehicle when adaptive cruise comes standard on a $23,000 Honda Civic.