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2020 GMC Sierra HD Review

Pickup trucks have become lifestyle accessories. The Class 2A Ford F-150, the Ram 1500, the Chevrolet Silverado and the GMC Sierra are among the best-selling vehicles in the country. The HD versions of these trucks, which are technically Class 2B and Class 3, are tools for serious work, specifically towing and hauling. After a 2019 redesign of its class 2A trucks, General Motors has overhauled its Class 2B and Class 3 pickups and will now sell an all-new 2020 GMC Sierra HD.

What’s New for 2020?

The GMC Sierra HD is all-new for 2020, with updated powertrains and a fresh exterior and interior design. In fact, it doesn’t share a single part number with the outgoing 2019 Sierra HD modelsSee the 2020 GMC Sierra 2500 models for sale near you or See the 2020 GMC Sierra 3500 models for sale near you

What We Like

  • The available class-leading maximum trailering of 35,500 lbs
  • Improved handling, both laden and unladen
  • The 6-function MultiPro tailgate, which is available on all trim levels

What We Don’t

  • The interior design lags behind those of competitors, especially in the base examples
  • A push toward the premium comes with higher prices

How Much?

The Sierra HD will be available in five trim levels: Sierra HD (starting at $40,000), SLE HD (prices TBA); SLT HD (prices TBA), AT4 HD (starting at $57,700), and Sierra Denali HD (starting at $63,700).

Fuel Economy

Sierra HD models have gross vehicle weight ratings (GVWR) over 8,500 pounds and are not subject to EPA fuel economy tests or ratings.

Standard Features and Options

The Sierra HD comes with a naturally aspirated (non-turbocharged) 6.6-liter V8 engine with direct gasoline injection. The engine is tuned to produce 401 horsepower and 464 lb-ft of torque. A 6.6-liter V8 Duramax turbodiesel engine is also available ($9,750 to $9,890). It uses common-rail direct fuel injection to churn out 445 hp and 910 lb-ft of torque. Rear-wheel drive is standard, and 4-wheel drive is available and even standard on the AT4 and the Denali.

Gas models get a Hydra-Matic 6-speed automatic transmission, while diesel models get a new 10-speed Allison automatic transmission. Configurations include the Regular Cab, the Double Cab and the Crew Cab (standard on the AT4 and the Denali). There is also the option of a standard bed or a long bed for an additional $200. Single rear wheels are standard on 2500 and 3500 models, and dual rear wheels are available on the 3500 models. Wheel sizes range from 17 inches to 20 inches, depending on the trim level. The front suspension is short-long-arms independent with torsion bars, while the rear suspension is a solid axle with a 3-stage, multi-leaf spring setup. Steering is hydraulic power-assisted and recirculating-ball-type with optional digital steering assistance. Four-wheel disc brakes with anti-lock braking systems (ABS) are standard.

Exterior features include LED daytime running lamps, headlamps and taillamps. LED fog lamps are also available. Both bed sizes include cargo-bed-side steps, integrated CornerSteps in the rear bumper and 12 fixed tie-down points. The 6-function MultiPro tailgate is available on the Sierra HD and the SLE HD, and standard on the SLT HD, the AT4 HD and the Denali HD.

GMC focused on the new AT4 HD trim level and the Denali HD at the launch event we attended in Jackson Hole, Wyoming. The AT4, a trim level which debuted on the Class 2A 2019 Sierra last year, is an off-road-capable model that comes with specific enhancements, including an off-road suspension with Rancho Shocks, skid plates and an Eaton locking rear differential, 18-in wheels (with 20-in wheels available) all-terrain tires, a traction control system (TCS) with off-road mode, hill-descent control and hill-start assistance, a 15-in heads-up display with an off-road Inclinometer, and an HD Surround Vision camera views for low-speed looks at terrain.

The interior gets a darkened trim on the steering wheel, center stack and sill plates and a Jet Black color scheme with Kalahari accents and live stitching. The seating is leather appointed with mini perforated inserts and embroidered AT4 badging on the headrests as well as all-weather floor liners. The exterior gets AT4 badging, dark chrome exterior finishes, front and rear bumpers in the body color, a rugged textured grille in black chrome finish and red vertical recovery hooks. Standard technology features include the ProGrade Trailering System, Onstar, 4G LTE Wi-Fi, SiriusXM Radio, USB ports, keyless open and start, remote start, and rear-seat reminder.

Optional packages include the $4,215 AT4 Premium Package, which comes with a universal home remote, a rear power-sliding mirror, a GMC Premium Infotainment System with navigation, an 8-in HD color touchscreen, voice recognition, Bluetooth audio streaming, Apple CarPlay and Android Auto, Bose Premium Sound, wireless charging, LED roof marker lights, front and rear parking assist, lane-change alerting with side blind-zone alerting, rear cross-traffic alerting, 20-in wheels and black assist steps. The $2,125 Technology Package includes HD Surround Vision, a rear camera mirror, a bed-view camera, a multi-color head-up display, and a multi-color 8-in digital driver information center.

Denali HD models come with the whole bag of chips — with practically every box checked. Still, you can add the Denali Ultimate Package ($2,870) to add HD Surround Vision, a rear camera mirror, a bed-view camera, a multicolor heads-up display and a power sunroof.


Driving a big pickup truck can lend a sense of security and safety, but it’s important to remember that all that mass can be deadly in encounters with vehicles, pedestrians and animals. ABS, TCS, Stabilitrak with trailer-sway control and hill-start assist, airbags, and teen-driver mode are standard. Additional safety and driver assistance systems are available on most trim levels and standard on the Denali. One example is the Driver Alert Package I, which comes with front and rear parking assist, lane-change alerting with side blind-zone alert, and rear cross-traffic alert. There is also Driver Alert Package II, which includes forward-collision warning, lane-departure warning, automatic emergency braking, Intellibeam headlamps, a following-distance Indicator, and a safety-alert seat.

Behind the Wheel

There’s so much to take in with such a big, complex truck like the Sierra HD. At the launch event we attended, all of the trucks available were either AT4 HD or Denali HD models equipped with diesel engines. We drove them with empty beds, with beds loaded with tree trunks, with gooseneck trailers attached and with bumper-pull trailers attached. In terms of comfort and convenience, the Sierra HD excels. It is easy to drive, quiet and roomy inside.

There’s little or no diesel engine clatter, and — with or without a load in the bed or trailer attached — the truck handles very well and rides smoothly despite its big size. The available torque from the diesel is impressive, and the 10-speed transmission makes use of it in every gear. It wouldn’t be a first choice for casual commuting because of its size, but the driving experience is a pleasure. A long trip in the Sierra HD would be a nice cruise.

If you tow a trailer, as GMC tells us that at least 90% of Sierra HD owners do on a pretty regular basis, there’s a ton of available technology to make your life easier. The Prograde Trailering System can be set up with up to 15 camera views, including the magical transparent-trailer view, which synthesizes multiple camera shots into a single moving image that gives the illusion of seeing right through the trailer. It’s not perfect (motorcycles and distant vehicles are very difficult to pick out), but it is comforting to be able to tell what’s behind you while you drive down the road.

Other extremely useful views make hooking up a trailer much easier, and you can even mount a camera inside your trailer to check on your cargo during a trip. Expert trailer haulers may scoff at the assistance, but most owners will greatly benefit from the package. A trailering app can even interface with certain brands of trailers to control and monitor trailer functions like HVAC or water and waste management.

Other Cars to Consider

2019 Ford Super Duty Starting at $33,150, the Super Duty got a complete makeover for 2019 and offers some stiff competition for the Sierra HD.

2019 Ram HDStarting at $33,645, the Ram HD also got a redesign for 2019 and may have the nicest interior of the bunch.

2020 Chevrolet Silverado HD Starting at $36,500 and riding on the same platform as the Sierra HD, the Silverado has many of the same available features and benefits but no MultiPro tailgate yet.

Autotrader’s Advice

The 2020 GMC Sierra HD is a serious truck with impressive capabilities. It arrives at a time when the competition is fierce and advantages are hard-won. Once you calculate your towing and hauling requirements and your desire for advanced and luxury features, you can see which HD truck suits your particular needs. It would be a heavy-duty job to make a bad choice in this class. Find a 2020 GMC Sierra 2500 for sale or Find a 2020 GMC Sierra 3500 for sale

To gain access to this information, Autotrader attended an event sponsored by the vehicle’s manufacturer.


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