2020 GMC Sierra 2500HD Review

The big bruisers of the GMC truck lineup, the 2020 GMC Sierra 2500HD and 3500HD, have been redesigned for more towing capability and more passenger comfort in a work-ready, full-size heavy-duty pickup. The Sierra HD is available in five trim levels with short and long bed options, dual rear-wheel and single rear-wheel configurations, and either a 6.6-liter gas V8 or a 6.6-liter Duramax diesel V8 engine.

The previous-generation Sierra HD maxed out towing-wise at less than 24,000 pounds so the new Sierra HD is considerably more than competitive with the upcoming the Ram and Ford F-Series heavy-duty trucks.

Smooth city! We tested the 2500 laden, empty, and hauling both a fifth-wheel and a bumper-mounted trailer and the ride quality was almost unchanged no matter what you threw in or behind the big Sierra. Throttle response was predictable, with minimal lag between the pedal and forward motion. The 6.6-liter Duramax and its accompanying Allison 10-speed transmission are well-matched and surprisingly quiet. Braking is made easier while towing through the use of an exhaust brake on the diesel. Despite the truck's size, maneuverability is good thanks to the large optional tow mirrors, big windows, low door height and multiple camera angles.

Interior design is not General Motors' current strength. Like the related Silverado, the Sierra interior is bland at best and dated at worst. What it lacks in visual appeal, though, it makes up in functionality and comfort. The seats are large and adjustable. The cabin is enormous, yet all necessary controls are within easy reach of the driver. The materials are soft and inoffensive, if not particularly thrilling. The infotainment and safety technology is easy to understand and quick to respond. The multi-color head-up display is a useful tool on the truck, especially when towing, as it allows the driver to make use of the tow cameras on the center screen while watching for navigation instructions without having to toggle between apps.

If a heavy-duty truck isn't practical, what's even its reason for being? In terms of usability, the Sierra HD is every bit the professional it's marketed as being. Despite its massive size — the Sierra HD has both a longer wheelbase and a taller overall height than the outgoing truck — the HD is easy and comfortable to drive without a load, and more impressively, it's easy and comfortable to drive with one. The ProGrade trailering system, which offers up to 15 views of the truck and trailer to aid in driving and parking, is astounding. While we wouldn't quite claim that it makes trailering stress-free, it certainly makes it safer for a beginner and offers extra reassurance for an expert. Camera angles include a side view that moves with the truck to help on curves, a transparent trailer view to see how many angry locals are lined up behind you, and the ability to add an in-trailer view to check on your tie-downs or camper cabinets.

GMC will be offering off-road-capable AT4 models across its range, and the Sierra HD is not an exception. On top of unique exterior and interior trim, the Sierra HD AT4 will be equipped with an off-road suspension, skid plates and a locking rear differential. For driver aids, the AT4 trim includes selectable off-road mode for the traction control system, along with hill descent control and hill start assist. The same cameras that help out with towing will use Surround Vision at low-speed for avoiding obstacles, and the 15-inch head-up display will project an off-road inclinometer as well.

For customers with regular towing needs, the GMC Sierra 2500 and 3500 HD trucks offer the physical capability plus some unique technology that can make the long haul safer for owner and crew.