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GMC's Burliest Pickup – The Denali Sierra HD

GMC Sierra HD pickups can pull a titanic amount of weight, but their Herculean efforts don't stop there.

These big-power workhorses clean up well, too, offering shiny chrome exterior bits and a comfortable leather saddle for the inside. The Sierra 2500HD and 3500HD are the jumbo-shrimp of their half-ton counterpart, the Sierra 1500, reviewed separately.

These GMC pickups offer a higher level of luxury and finish versus Chevy's Silverado HD offerings.

A 401-hp 6.6-liter V-8 with a 10-speed automatic serves as the base powertrain, while an available 470-hp Duramax turbodiesel V-8 with 10-speed automatic transmission is a prerequisite for the Sierra HD's 22,500 pounds of maximum conventional towing.

Additional trailer assist features such as Transparent Trailer View, Trailer Side Blind Zone Alert, and available adaptive cruise control with trailering make the Sierra HD work smarter instead of harder.

What's New for 2024?

GMC's burliest pickup gets a light visual refreshing among larger changes such as a revised powertrain that offers more towing capacity and an all-new trim. The Sierra HDs get a revised front fascia with newly available LED headlights and taillights with sequential turn signals.

The 6.6-liter Duramax turbocharged diesel V-8's power and torque have increased to 470 horsepower and 975 pound-feet of torque respectively. The increased power has increased the towing capacity across the Sierra 2500HD and 3500HD lineup, with a higher max rating of 22,500 pounds at the hitch. The 401-hp 6.6-liter V-8 gas engine's six-speed automatic is replaced by the Allison-certified 10-speed automatic, previously exclusive for the diesel engine.

An all-new Denali Ultimate trim joins 2500HD and 3500HD and offers an even greater level of luxury than the popular Denali tier. Denali Ultimate, just as it does for Sierra 1500, adds leather-wrapped door panels, steering wheel, and A- and B-pillar handles. The 16-way power-adjustable front heated and cooled messaging front seats are also given intricate leather stitching with a topographic map of Mount Denali in Alaska.

These revisions are supplemented by new trailering technology, including adaptive cruise control with trailering, gross combination weight (GCW) alert, and GM's Transparent Trailer View is now also compatible for gooseneck and fifth wheel trailering.

The Sierra HD's standard driver assistance tech has also been expanded for 2024. Included in the addition of the AT4X off-road trim, there's also an AEV Edition that comes with steel bumpers, AEV 18-inch wheels, and stronger skid plates.

Engine, Transmission, and Performance

The Sierra HD comes standard with a gas-powered 6.6-liter V-8 that generates 401 horsepower and 464 pound-feet of torque. It pairs with a 10-speed automatic transmission and rear- or four-wheel drive.

The optional Duramax diesel 6.6-liter V-8 cranks out 470 ponies and 975 pound-feet of twist, and it works through an Allison-certified 10-speed automatic. You can also specify either a single- or dual-rear-wheel axle (known as a "dually") for 3500 HD models.

There's no arguing that the Duramax is a highlight of the heavy-duty Sierra, and it's a no-brainer for those who regularly tow substantial loads. The engine is surprisingly refined, and the transmission is very responsive. Together they help the 2500HD Denali achieve impressively quick acceleration times. The gigantic GMC also has an agreeable ride quality for its breed.

Interior, Comfort, and Cargo

Inside, the Sierra 2500HD and 3500HD have a huge dashboard that hosts user-friendly switchgear. Most models have a split-folding front bench that can be replaced with a pair of bucket seats and a full centre console. The Sierra's interior can also be optioned with a head-up display, a heated steering wheel, heated-and-cooled front seats, and wireless charging.

The new Denali Ultimate trim is as grandeur as it gets, with leather-wrapped interior pieces, Paldao wood trim pieces, and a soft microsuede headliner. The Sierra HD will please pickup-truck buyers who prioritize practicality and versatility.

Along with extensive passenger space in the crew cab, the GMC is littered with handy interior cubby storage. Its standard and long cargo boxes have built-in steps on both sides of the bed and the rear bumper has them at each corner. The box can be further customized with LED lighting, movable tie-downs, and a 120-volt outlet.

The heavy-duty Sierra's biggest showpiece is its innovative multi-function tailgate, which has six different positions that include a work surface and bench. It's a tailgater's dream come true.

Infotainment and Connectivity

Every Sierra HD has a standard touchscreen infotainment system with Apple CarPlay and Android Auto. While base models have fewer options, they can still be outfitted with a 120-volt outlet and a mobile hotspot.

Most trim levels have an 8.0-inch screen and additional charging ports. All systems include a set of rotary knobs and physical buttons that are easily accessible. The larger touchscreen can be upgraded with built-in navigation, a Bose audio system, SiriusXM satellite radio, and a rear-seat entertainment system.

A massive 13.4-inch infotainment touchscreen offers the most integrated experience with features like Google Built-in, split-screen navigation, and is wireless Apple CarPlay and Android Auto compatible. This display is standard on Denali and Denali Ultimate trims.

GMC also offers a smartphone app that can be used to remotely control trailer functions. Likewise, the truck's infotainment system allows users to store different trailer profiles to monitor maintenance.


A 13.4" diagonal tablet-style touch-screen—the largest in its class—customisable, high-tech centerpiece of the cabin.

Safety and Driver-Assistance Features

GMC has a comprehensive camera system that features up to 15 different viewing modes, including a "transparent" mode that allows the user to virtually see through an attached trailer as if it wasn't there.

For more information about the Sierra HD's crash-test results, visit the National Highway Traffic Safety Administration (NHTSA) and Insurance Institute for Highway Safety (IIHS) websites.

Key safety features include:

  • Standard forward-collision warning and automated emergency braking

  • Standard lane-departure warning

  • Available blind-spot monitoring and rear cross-traffic alert

Written by Austin Irwin & Eric Stafford Car and Driver - Adapted by Vas Comblas


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