2024 GMC Sierra HD: High Luxury Meets High Limits

• New Denali Ultimate expands luxury standard for heavy-duty trucks
• Revised diesel V8 makes 25% more torque and sets higher towing limits
• Ten-speed transmission now standard for both gas and diesel engines
• Part of the fourth Sierra 2500HD generation introduced for 2020

What's under the Sierra HD's hood?

An updated 6.6-liter diesel V8 massaged for 25% more torque and even loftier tow limits. It makes 470 horsepower and 975 lb-ft of torque, both healthy bumps from today's rating of 445 hp and 910 lb-ft of torque. GMC says the gains come from a more efficient turbocharger design, new electronic control unit (ECU) programming and revised cylinder heads.

The stronger diesel also helps increase the towing limit for the 2500HD and 3500HD models, which rises to 20,000 pounds for conventional trailering. For gooseneck and fifth-wheel towing, the limits increase to 22,500 pounds for 2500HD models and 36,000 pounds for the 3500HD.

Even models with the standard V8 gas engine get a towing boost, with double- and crew-cab models adding about 1,500 pounds of capability. A larger grille design with increased airflow and cooling helps, no doubt, but some credit is due to the 10-speed automatic Allison transmission that now comes standard with the gas V8, replacing an aging six-speed unit. The 10-speed features smaller steps between gears, allowing the engine to remain near its peak power for longer.

How's the Sierra HD's interior?

The new Denali Ultimate trim promises new extremes in cosseting and comfort, with full-grain leather covering seats, door panels, dash top, and most any other touchable surface, save for the open-pore wood accents. The headliner, visors and windshield pillars will come wrapped in microsuede, while front passengers will rest on 16-way power-adjustable, massaging front seats. A sunroof, digital rearview mirror, 15-inch color head-up display and Kicker audio system will also come standard, while a 12-speaker Bose system will be optional.

How's the Sierra HD's tech?

The Sierra HD's higher tow ratings are complemented by a mix of trailering safety and convenience features. Drivers will now be able to use adaptive cruise control when trailering, with the system able to compensate for additional drag and longer braking distances. Blind-spot monitoring is also extended to areas around a trailer, and new sensors will be able to tell if vehicle and trailer weight exceed the truck's gross combined weight rating.

Anyone who's towed before knows spatial awareness is crucial, and to that end the Sierra HD offers up to 14 camera views. The Transparent Trailer View uses cameras at the back of the truck and trailer to effectively make the trailer disappear from the screen display, offering a better real-time perspective of objects around the truck and trailer. In the 2024 Sierra HD, this feature is upgraded to work with gooseneck and fifth-wheel trailers.

Other helpful views include a close-up of the hitch receiver, a cargo bed view and a full-length side view when attempting lane changes with a trailer. All of these angles can be run through an optional 13.4-inch touchscreen display that offers split-screen capability and anchors an infotainment system that include wireless Apple CarPlay and Android Auto smartphone connectivity and Google feature integration. A 12.3-inch digital gauge display will also be available.

Today's Sierra HD comes with most standard driver assistance features, including automatic emergency braking and lane departure warning, but for 2024, pedestrian detection is included. The optional Pro Safety Plus package adds rear cross-traffic braking and trailer area blind-spot monitoring. 

Edmunds says

Some truck buyers want high limits and high standards of luxury. GMC delivers with the new heavy-duty Denali Unlimited.