The Breakdown

The 2020 GMC Sierra HD might not be class-leading in horsepower or torque, but its technology makes it arguably the best truck to tow with. It’s the best it has ever been, and if you need to make towing easy and comfortable, this is your truck.
Overall
Pros
Excellent towing technology / Strong engines / Easy to use infotainment system / Attractive exterior / Optional Carbon Pro bed / Unique tailgate design
Cons
Interior materials could be better / Not class leading for horsepower or torque / More expensive than its Chevy Silverado cousin

GMC has a new truck for 2020, just like its sister brand Chevrolet. I drove the GMC Sierra HD in Bend, Oregon, not long ago and found it to be an excellent HD pickup. 

The GMC Sierra follows much of the same playbook as that truck, so you might expect me to say it’s just as good. I’m not going to say that. The GMC is better. If only slightly. GMC managed to take essentially the same truck as the Chevy and make it just special enough. 

My Time With the Vehicle

The company invited me out the Jackson Hole, Wyoming, to drive the new 2020 Silverado HD, the 2020 Silverado 1500 Duramax (a review of that truck will come at a later date), and the new 2020 Acadia AT4. I got to spend the better part of two days in the truck. Towing, off-roading, and hauling all over. 

The GMC Sierra trickled down to fifth place overall in trucks below the Ford F-Series, Ram Pickup, Chevy Silverado, and Toyota Tacoma. This is for all versions of the trucks and not just the heavy-duty trucks.

GMC sells higher priced machines and manages to mostly cater to a more affluent customer. The Sierra’s unique offerings and its place in a more premium space of the truck market make it a very important truck for the segment. 

What Is It?

2020 GMC Sierra HD towing a trailer

The 2020 Sierra HD fits into the heavy-duty truck segment. It’s designed for buyers who have heavy loads to tow and haul. The Sierra HD’s max conventional towing capacity is 20,000 pounds when properly equipped, max fifth-wheel towing capacity is 35,000 pounds when properly equipped, and payload capacity is 6,532 pounds when properly equipped. 

Those aren’t the highest numbers in the segment, but they’re more than enough for the vast majority of buyers. 

When you look at the Sierra HD in terms of how it compares with the others in the segment, it’s a bit of an outlier in that the company purposely focuses on more affluent buyers. GMC sees itself as the only premium SUV and truck brand. The company is the only one out there catering specifically to the premium market. 

Despite this, Ford, Chevy, and especially Ram all offer high trim levels of their trucks that are right on par with the Sierra HD and arguably more luxurious and premium in some cases. This comes down to marketing. GMC says it’s a premium brand, even if I were to say it was not, they still would claim to be higher in the food chain, but the lines get blurred. 

In the end, all you need to know is that this is a nice truck built for people who want something with a little more prestige than a Ford, Chevy, or Ram. 

The Trims, Configurations, and Powertrains

2020 GMC Sierra HD aT4

GMC like Chevy and the rest of the competition offers the Sierra HD in 2500 and 3500 variants. The truck can be had with a regular cab, double cab, or crew cab. You can get two or four-wheel drive and get the vehicle in a dually if you would like. 

As far as trim levels go, there’s the base Sierra, SLE, SLT, AT4, and Denali. The AT4 is the off-road version of the truck. It’s essentially the Chevy Silverado Trailboss of the GMC range and brings considerable off-road equipment to the model while still providing ample towing prowess. 

In the GMC Sierra HD, you have the choice of two engines. They are the same choices as the Chevy Silverado HD. There’s the 6.6-liter V8 gasoline engine that makes 401 hp and 464 lb-ft of torque. There’s also a Duramax 6.6-liter V8 turbodiesel that makes 445 hp and 910 lb-ft of torque. This is the engine everyone wants and should want. 

The Exterior

2020 GMC Sierra HD

One of the GMC Sierra HD’s best qualities is its exterior styling. The truck is truly handsome in an age when most HD trucks look like a big ass air conditioner on truck-sized wheels. Ford and Chevy have distinct—but I think ugly—styling right now. Ram is doing better, but GMC takes the cake. 

The exterior of the HD is bold and handsome. The exterior design folks at GMC told us that the beltline of the vehicle was actually brought down to improve sightlines. It also looks better to me. The top of the bed, too, was brought down to improve sightlines and make it easier to tow things like a fifth wheel without having to worry about damaging the top of the bed accidentally.

It’s a purposely crafted design that’s also handsome. GMC left the sides of the doors smooth so you can put your company logo on the side of the door easily. They could have got all funky and did some creases there but chose not to. 

When I look at the GMC, I appreciate the level of restraint. Sure, the big chrome grille on the Denali model can seem a little gaudy, but other than that, this is a classy HD truck. 

2020 GMC Sierra HD front

You can say similar things for the AT4 off-roader. The truck features more of a blacked-out aesthetic. I’m not one to say that black equals rugged like some people, but I do think the back looks good. GMC didn’t go over-the-top as Ram does with the Power Wagon, again it’s a bold and somewhat sophisticated look. The AT4 has a little more attitude, but it doesn’t scream at you. It features goodies like off-road suspension, Rancho Shocks, skid plates, Eaton locking rear differential, 18-inch wheels, Michelin all-terrain tires, traction select system, hill descent control, hill start assist, and HD surround-view camera views for seeing the vehicle surroundings at low speed. 

There are two elements of the GMC Sierra’s exterior that you really need to know about. The first is the company’s MultiPro Tailgate and the CarbonPro bed. The MultiPro Tailgate is a Unique tailgate that offers six different functions and can be fitted with a Kicker audio system. 

The CarbonPro bed is the first carbon fiber bed in the industry. It’s supposed to be stronger than steel or aluminum. I think it’s great, but it won’t be an inexpensive thing to replace if it does get damaged. 

2020 GMC Sierra HD carbonpro bed crack

GMC gave us a chance to beat the heck out of the bed with bats, golf clubs, cinder blocks and more. I managed to break a golf club on the bed and in the process put a tiny crack in the bed (pictured above). Other folks attempts to damage the bed proved futile. It’s one seriously tough bed. 

These two special features set the GMC apart, especially in terms of GM products. They’re exclusive to GMC.

The Interior

2020 GMC Sierra HD AT4 Interior
Image provided by GMC

The interior is where GMC struggles—this is true of Chevy, too. I don’t know who does the interior design for GM’s products, but they need to really study the competition and take some notes. 

This is specifically true when it comes to interior materials. I would love for GMC to put real wood trim in. Fake wood cheapens the whole cabin. Also, I don’t know where GM gets some of its cheaper looking plastics, but it features them in all of their brands and vehicles. 

Maybe GM has a good partnership with the company supplying these materials. Maybe it seems like a great idea to put these low-quality plastics in all vehicles to cut costs. It isn’t, especially in the GMC Sierra. It’s supposed to be a premium truck. Cheap plastic pieces on the doors and center console are a bad idea and are the chief contributing factor to me questioning whether this is really a luxury vehicle. 

The GMC Sierra HD should have real aluminum and wood trim. There will still be plastics because everyone uses plastics these days, but the paper-thin flip-up covers on the auxiliary power outlets have to go, the cheap-feeling fake wood plastic trim needs to disappear, and the center console should be a thing of beauty. Leave the cheaper materials to Chevy where it belongs. 

Towing Technology

2020 GMC Sierra HD
Image provided by GMC

The GMC Sierra HD comes with the company’s ProGrade trailering technology. This tech is available on Chevrolet’s trucks and GMC’s light-duty trucks, too. It includes a class-leading 15 different camera views.

All of these views help make hitching up and towing a trailer extremely interesting. You can use these trailering views while you’re going down the road to see in blind spots and directly behind the trailer. The most interesting view is the transparent trailer view. In this view, the camera on the back of the trailer (sold as an accessory) and the cameras to either side of the trailer stitch together a view, making it look like there is no trailer behind the truck.

2020 GMC Sierra HD
Image provided by GMC

It takes a little getting used to at first to use the cameras to their fullest extent, but once you get used to them, the camera views make towing even giant trailers extremely easy.

In addition to the trailering views, there’s also an app that can interface with your RV if you have one that features the iN-Command control system from ASA electronics. GMC worked with the company to help make this happen. You can turn on the RV’s AC unit before you get to your campground, deploy awnings from the app, and do other basic functions like turning on lights.

The Rest of the Technology

2020 GMC Sierra HD Denali Interior
Image provided by GMC

The GMC Sierra also comes with a slew of other driver technology and an updated infotainment system providing access to Apple CarPlay, Android Auto, Bluetooth connectivity, OnStar services, and a whole lot more. There’s also an automatic electric park brake, park grade hold assist, an integrated trailer brake controller that works with the smartphone app, hill start assist, hill descent control trailer sway control, adaptive cruise control is coming.

The truck will also get a new 15-inch color heads up display that’s configurable. It’s really handy and showcases navigation turn-by-turn directions, speed information, lane information, and more. It’s one of the best out there and can be adjusted for height and whatnot, too.

Overall, the GMC technology is good and on-par with the segment. The HUD is a nice thing that sets it apart a bit, but its the trailering technology—specifically the camera views— that are a true game-changer.

How Big Is It?

2020 GMC Sierra HD towing

The GMC Sierra HD is, as you’d expect a big truck to be, extremely large. The truck measures 250 inches with the crew cab and standard box and 266 inches with the long bed (about 22 ft long). It feels big on the road, but not unwieldy. GM has done a good job of making its big trucks easy to manage. Also, the technology helps a lot. 

You will have trouble getting this truck in a typical garage. However, that can be said of all HD trucks these days. They’re all large, and the GMC isn’t really any larger than its competition. The tucks are big and meant to be. 

One note on size is that the carbon fiber bed that GMC has in its vehicle allows for excellent cargo volume even with the lower beltline. The company managed to make sure there was no extra space between the interior of the bed and the exterior of the truck’s body. By removing that space, the bed is truly cavernous. 

Does It Work?

2020 GMC Sierra HD front three quarter

I towed a 12,000-pound trailer up and down mountain roads, towed 30,000 pounds at one point around a small course, went off-roading at a 300-acre ranch, and hauled 2,000 pounds of logs up and down the mountains around Jackson Hole. 

So, does it work? Yes. Just like I expected. The GMC works as well in every regard as the Silverado. The engine options, technology, and much of the interior are all the same. It’s more attractive in my opinion and the MultiPro tailgate and optional Carbon-Pro bed help make the model more than most other pickups on the road. 

Is it perfect? Of course not. It suffers from many of the same minor pitfalls as the Silverado and fails at greatness if only slightly. The truck is good, darn good, and the one that I would probably pick if I had a large box trailer, horse trailer, or camper to tow. Still, there are some things I would gripe about. 

First and foremost is the cheap-feeling plastic inside the cabin. Most of the cabin materials are top-quality, but the cheaper pieces of plastic in this truck have to go. It’s a premium truck. It needs to lose the cheap fake wood (how about real wood?) and eliminate any cheap plastic in the cabin. 

Then there’s the question of if GMC’s truck is really a more premium product. It certainly caters to that audience, but the differences between GMC and Chevy feel small and I wonder if that’s really enough to justify GMC saying it’s a premium automaker. 

Again, these are nit-picks. This HD pickup is an excellent machine and a true beast. It tows heavy loads with ease and the camera system makes doing so easier and less stressful than ever before. 

Does It Justify Its Price?

2020 GMC Sierra HD front

If you’re reading this review and you like all the stuff mentioned above but don’t need a fancy tailgate, a carbon bed, or then buy the Chevy Silverado. It’s ugly, but you’ll save money going with the Chevy. 

The GMC Sierra HD in its most basic form is $37,195 for the 2500 regular-cab long bed. This is more expensive than the competition by about $1500 at the very least. As you climb the ladder the GMC stays more expensive. 

Most of the trucks I drove (there were several) were priced around $80,000. This is typical for a true HD towing machine these days regardless of manufacturer. These models came with some of the best technology in the business and most of the best features. 

So, if you want some prestige, a bit more of a luxury feel overall, better looks, and access to some fancy features like the CarbonPro bed and the Multi-Function tailgate, then the GMC may just justify its price. 

Personally, I’d consider saving some money by buying the Chevy. However, the Chevy is a true uggo, whereas GMC’s truck is handsome. The price delta might be worth it for that reason alone. Who wants to come out to an ugly vehicle every friggin morning? 

What’s the Verdict?

2020 GMC Sierra HD in a row

In the end, it comes down to what you want. If you just want supreme power and excellent towing chops with the best towing assistance technology in the industry, then you buy the Chevy Silverado. 

If, however, you want your HD truck with a bit more prestige, for it to not look like it got beat with an ugly stick and have access to fancy things like a carbon-fiber bed and a new tailgate design, then you buy the GMC. 

Then we have the AT4. The closest competitor here is really Silverado Trail Boss or the Ram Powerwagon. The AT4 is an interesting proposition. It’s a heavy-duty truck that doesn’t suffer much in the towing and hauling department and can off-road like nobody’s business. If you need a towing machine, but also plan on doing some hardcore off-roading, GMC has your truck. 

In the end, you have to be ready to shell out some serious dough for a heavy-duty truck these days no matter what brand you choose. In terms of GMC, you have to decide if the small things that set it apart are worth it. There’s no doubt the truck is impressive but is it impressive enough? That is a question that each person will answer differently. For me, it is. 

Specifications

  • Base Price: $37,195 (2500 regular cab, long bed)
  • Price as Tested: Prices varied but most were around $80,000
  • Drive Type: 2×4 and 4×4
  • Engine: 6.6-liter V8 or Duramax 6.6-liter V8 turbodiesel
  • Transmission: 6-speed automatic (gas engine), 10-speed automatic (diesel engine)
  • Power Output: 401 hp and 464 lb-ft of torque (gas engine), 445 hp and 910 lb-ft of torque (diesel engine)
  • EPA: NA
  • Optional Equipment: List not provided with vehicles that were driven.