First Drive: 2020 GMC Sierra HD Tows Well but Needs Interior Upgrade

August 26, 2019 by Jerry Hirsch, @Jerryhirsch

Recent automaker stunts using diesel and electric trucks to tow yachts, semi-truck combos and trains are fun but don’t have much real-world value.

Towing 30,000 pounds of metal with a 9,000-pound 2020 GMC Sierra HD diesel engine pickup is a better test of the everyday tasks trucks must perform.

GMC provided that opportunity at a product briefing and drive of its new-generation Sierra HD in Wyoming last week. The truck is a complete redesign from previous models. It has a purpose-built, beefier architecture from the also-redesigned 2020 Sierra half-ton pickup. The truck has a longer wheelbase and is taller than the model it replaces.


The new Sierra HD proved itself an able workhorse loaded with driver-assistance technology that reduces the stress of the often-daunting task of hauling trailers and heavy loads.

2020 GMC Sierra HD

The 2020 GMC Sierra HD proved its towing mettle during a drive in Wyoming, hauling seriously large loads, including 30,000 pounds of metal. (Photo: GMC)

The combined weight of the 2020 GMC Sierra HD and load in that one test is equivalent to half of a loaded big rig and trailer. That sounds intimidating, but the truck accelerated assuredly, steering through turns without wobble or strain and braking as expected. (Anyone towing a big load must remember to allow more space to brake.)

Hauling smaller loads such as an 11,000-pound Keystone Alpine RV was a breeze. The truck felt even more planted and secure running bobtail while carrying a 2,000-pound load of logs in the bed.

The new truck’s capability starts with its Duramax 6.6-liter turbo-diesel engine. An option for the Sierra HD and its sibling, the Chevrolet Silverado HD pickup, it offers high torque, high power and low noise under most conditions. However, the engine occasionally chatters on grades and under strain, the powertrain’s only drawback. It added a bit of a growl towing a box trailer loaded with 14,000 pounds of cement to the Idaho border. The Duramax produces up to 445 horsepower and 910 pound-feet of torque. A newly designed, smooth-shifting 10-speed Allison automatic transmission rounds out the powertrain.


The robust engine is the heart of the truck, but new technology also makes towing easier.

GMC’s ProGrade Trailering system offers a class-leading available 15 camera views. The best feature stitches the images together to provide a real-time “transparent” view to what is behind the trailer. It allows the driver to see if a vehicle is tailgating or wants to pass, or if lane-splitting motorcycles are coming up behind the truck. This supplements larger, door-mounted trailering mirrors.

2020 GMC Sierra HD

The ProGrade Trailering system in the Sierra HD provides 15 camera views that can show a real-time “transparent” view of what’s behind the trailer. (Photo: GMC)

The higher trim levels have blind-spot monitoring that extends along the trailer line and helps alert the driver to potential hazards. They also have another helpful safety feature: forward-collision alert with automatic emergency braking.

There’s an optional available 15-inch diagonal head-up display that offers useful trailering information, including vehicle speed, navigation information and an inclinometer display for the road grade. But the view can wash out with certain eyeglass lenses or sun positions.


Another option is the iN∙Command control system that integrates with the truck’s touch screen to allow the driver to monitor and control select functions of compatibly equipped trailers. The driver can start the air conditioning or heater to condition the trailer as the truck approaches its destination. The app can turn on lights, start a generator and execute other functions.

2020 GMC Sierra HD

Towing this 11,000-pound Keystone Alpine RV, the Sierra HD barely broke a sweat. (Photo: Jerry Hirsch/

The new diesel Sierra HD is optimized for towing in just about every way. It can tow up to 35,500 pounds and has a gross combined vehicle capacity of 43,500. But it is not perfect.


General Motors, GMC’s corporate parent, is positioning the brand as an upscale truck. The average transaction price of GMC’s Denali trim line is north of $54,000. That sandwiches between the average transaction price for Mercedes-Benz and BMW vehicles in the U.S. A full 98 percent of diesel Sierra HD crew cab truck sales hit at least $60,000.

The interior doesn’t match any luxury brand makes and is far behind the top trims of rivals Ford and Ram. A Ram Laramie Longhorn trim level, for example, offers finely stitched leather interior with wood accents. Tooled buckles fasten the seatback pockets in the second row. A 12-inch touch screen anchors the cabin. Acoustic glass reduces road noise.

2020 GMC Sierra HD

The 2020 GMC Sierra HD’s interior is made for rugged use, the manufacturer says. (Photo: GMC)

The Sierra Denali doesn’t come close. The center console and 8-inch touch screen look like they come from a Chevrolet Malibu sedan. There’s leather, but it is far from rich and supple. Hard plastic abounds. The few wooden accents feel and look like plastic. The GMC Denali interior needs a complete redesign. It doesn’t match the effort put into the mechanics of the truck, and it certainly is not luxury.


GMC designers say upgrades are coming. But they also point out that whether the HD is pulling a giant RV to the lake or pulling into a construction site, the truck is designed to work. That means the interior also must be mud- and blood-proof. The trick is finding the perfect compromise between rugged and luxurious.

It’s a valid point. More than 93 percent of GMC Sierra HD buyers purchase the truck to tow. The biggest segment tows a large camper or fifth wheel. And half of the buyers pull 8,000 pounds or more.

If that’s the new diesel Sierra HD’s most important mission, the truck passes the test.

Editor’s note: To facilitate this report, attended an event at which GMC hosted travel and lodging.

Ryan ZumMallen January 22, 2019
The redesigned 2020 GMC Sierra HD relies on towing technology and an off-road variant to stand apart in the intensifying heavy-duty pickup truck segment.

One Response

  1. Steve Nash

    $54,000 for the Denali? Prices I’m seeing is over $20,000 above that. Am I missing something?


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