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2020 GMC Sierra 1500 Duramax Diesel

2020 GMC Sierra 1500 Duramax Diesel

GMC’s Sierra 1500 came out as a new model in 2019, and it’s a seriously good model. General Motors created a heck of a pickup for both the Chevrolet and GMC brands and each brand has its own unique spin on the vehicle. 

While the Chevy Silverado and GMC Sierra share a lot of the same parts, components, and tech, GMC does have a couple of things that set it apart from its bowtie brethren. This makes it worthy of your attention and consideration. 

My Time With the Vehicle

GMC flew me out to Jackson Hole, Wyoming, to drive the new 1500 Duramax version of the truck as well as the Sierra HD and write some reviews. I got to spend two days with the HD and the 1500 Duramax. 

While my time in the 1500 Duramax wasn’t quite as extensive as it was with the HD, I will say I definitely had enough time to evaluate the truck properly. 

The GMC Sierra sits in fifth place overall in truck sales. It now sits behind the Ford F-Series, Ram Pickup, Chevy Silverado, and Toyota Tacoma. This is for all versions of the Sierra (HD and otherwise). 

Despite this, the company seems to be doing well due to the fact that the GMC brand caters to more affluent customers. It’s an important truck for the segment. 

What Is It?

2020 GMC Sierra 1500 Duramax Diesel

The 2020 Sierra 1500 is a light-duty, full-size pickup truck. It’s designed for buyers who need a truck that can do everything—tow, haul, get groceries, etc. The new diesel version of the truck adds another flavor to the recipe. 

The truck with the Duramax diesel can tow up to 9,100 pounds and it can haul up to 2,240 pounds. The truck is as much a workhorse as it is an everyday driver. 

GMC calls itself a premium automaker. It says it’s the only premium SUV and truck manufacturer in the country. While it does cater to a more affluent customer, I see few differences between the GMC products and the higher trim level pickups from other automakers. 

There is a little more prestige with the GMC brand, but the Sierra 1500 doesn’t feel all that much more luxurious or special than trucks from Chevrolet, Ford, and Ram. 

The Trims, Configurations, and Powertrains

2020 GMC Sierra 1500 Duramax Diesel

GMC, like Chevrolet, offers its 1500 truck in regular, double cab or crew cab. You can get two or four-wheel drive, and there are six different trim levels: Sierra, SLE, Elevation, SLT, AT4, and Denali. The Denali trim level is the luxurious one and the AT4 trim level is the off-roading trim level. 

When it comes to engines, there are a lot of choices. GMC offers a 2.7-liter turbocharged four-cylinder, a 4.3-liter V6, a 5.3-liter V8, a 6.2-liter V8, and finally the 3.0-liter turbo diesel straight-six. Depending on the engine you’ll get either a six-speed automatic, and eight-speed automatic, or a 10-speed automatic. 

I drove only the Duramax diesel engine. It comes with a 10-speed automatic transmission and makes 277 hp and 460 lb-ft of torque. It also manages 23 mpg city, 30 mpg highway, and 26 mpg combined. The gas mileage is impressive but not as good as Chevrolet, surprisingly. 

The Exterior

2020 GMC Sierra 1500 Duramax Diesel

In terms of the exterior, I wouldn’t say the GMC Sierra 1500 is as good looking as the HD pickup. That truck just looks better with its lower beltline and lower bed height. However, the GMC looks far better than the Chevrolet Silverado. Chevy’s truck is too edgy and busy of a design for me. 

GMC’s Sierra is more subdued and a little more mature in the styling department than Chevrolet’s truck. This is especially true when you look at the AT4, which is the off-road trim level. GMC did a good job of making the truck look a little more aggressive, but it didn’t go full whacko crazy with the styling. The designers give it blacked-out accents and more or less left the rest alone. In short, the GMC is one of the best-looking full-size pickups on the market. 

Two other parts of the exterior I need to discuss are the carbon fiber bed and the MuliPro tailgate that GMC has. The tailgate offers six different ways it can be used and is a serious innovation. It looks cool and offers functionality no other truck can match. 

The carbon fiber bed is another GMC exclusive. GMC had us journalists beat the crap out of one of the beds with baseball bats, bricks, and golf clubs. The golf club was the only thing that did any damage, you can read more about that in my Sierra HD review. Basically, the carbon fiber bed is extremely tough. However, I wonder how difficult and expensive it is to replace if it were to be damaged in an accident. 

The Interior

2020 GMC Sierra 1500 Duramax Diesel
Image from GMC

As you might expect, the Sierra struggles in the interior department. The cabin is ergonomically fine, but from a styling and interior materials standpoint, it’s lacking. 

Interior materials are the true issue here. As I mentioned in my review of the Sierra HD, the cheaper plastics, fake wood trim, and fake metal in some cases has to go. GMC is supposed to be a premium automaker, and it needs to have premium level materials throughout the entire cabin. 

Right now, there are a lot of good things in the cabin. The seating upholstery is good, many parts of the dash look handsome and offer good quality materials, but the center stack, center console, and doors all have cheap plastic on them. If you cut out the cheap plastic and replaced it with something else, you’d have a true premium truck.

Towing Technology

2020 GMC Sierra HD
Image from GMC

GMC’s Sierra can be had with the company’s ProGrade trailering technology. This technology is designed to make towing as easy as possible. It works well. 

There are 15 different camera views. All of these views help make the truck easier to drive when towing a trailer. The one that’s most impressive is the transparent trailer view. It stitches together a special view using the rear-view camera and the side cameras to make it look like the trailer has almost disappeared. It’s especially handy with big-box trailers or a camper. 

The trailering technology can take some getting used to, but once you do, you’ll love the tech. Also, GMC has partnered with ASA so that it can interface with the company’s iN-Command control system. This system connects with an RV and allows you to control the RV’s systems from the truck. This means you can be rolling down the road and turn on your RV’s AC unit before you get to your campground. 

The Rest of the Technology

2020 GMC Sierra 1500 Duramax Diesel
Image from GMC

In terms of the rest of the technology in the truck, GMC hasn’t skimped on much of anything. There’s a high-quality infotainment system that provides drivers with access to 4G LTE Wi-Fi, Apple CarPlay, Android Auto, Bluetooth connectivity, OnStar services and more. 

The truck also gets a multi-color heads-up display that measures three inches by seven inches. You get information like your speed, the speed limit, turn-by-turn navigation, cruise control status, and lane position. GMC isn’t lacking when it comes to technology in this truck. 

How Big Is It?

2020 GMC Sierra 1500 Duramax Diesel

In its largest configuration, the GMC Sierra measures 241.3 inches in length, 81.2 inches in width, and 75.5-inches in height. 

That’s right in line with Ford, Ram, and Chevrolet’s pickup trucks. It is a little larger than some of the competition, but it doesn’t feel it on the road. One thing to note is that full-size trucks (all full-size trucks) are almost too large to fit in most people’s garages these days. 

Before you run out and buy one, think about the size of your garage or parking area and make sure it will fit. If it won’t consider a midsize truck, there are plenty out there and many offer good towing and hauling numbers. 

Does It Work?

2020 GMC Sierra 1500 Duramax Diesel

Yes, it does. The GMC 1500 Duramax Diesel does its job. I got to tow right around 8,000 pounds up and down mountain roads and had no issues. The 10-speed automatic transmission is quite good. 

Your specific 1500, should you buy one will have a handy sticker inside the door telling you how much the truck can handle. Because these are VIN specific, you’ll know exactly for your specific truck.

I also got to take an AT4 version of the truck through a pretty rigorous off-road course put together by GM. The truck handled a tall rock climb and giant muddy bog area with ease. The AT4 is essentially GMC’s version of the Trail Boss. It comes with a two-inch lift, updated suspension, Rancho shocks, 18-inch wheels, hill descent control, traction control, and Goodyear Wrangler DuraTrac tires.

The truck works as an everyday vehicle, too. The cabin is comfortable and the truck easy to maneuver on the road. There’s plenty of room for storage, and the infotainment technology and driver aids work well. 

My only real complaint is the fact that some of the interior materials look and feel cheap. This is something that was less of a problem in the Chevrolet Silverado. I still mentioned it, but it’s less of a problem. GMC is supposed to be a premium automaker, and its interior materials need to reflect this, especially in the Denali trim level. 

Does It Justify Its Price?

2020 GMC Sierra 1500 Duramax Diesel

The GMC Sierra 1500 starts at $29,600. That’s for the base model with a regular cab. It is affordable. However, it’s on the upper end. This is expected for GMC as it’s supposed to be a little higher on the prestige scale than say Chevy or Ford. 

The diesel engine is a good addition to the truck and one that I think is probably worth it. GMC charges $2,495 more than the 5.3-liter V8 engine for the Duramax. This is a pretty big chunk of change, but it’s not an outrageous amount. The engine is smooth, powerful, and much more efficient than the V8. If I were buying, I’d think about forking over the extra money. 

GMC also charges less for the upgrade than the competition. Ford and Ram both charge more for the diesel. 

Then we have the question of should you buy the GMC or Chevy? This is a tough one. For the non-diesel crowd, it’s easier. All you have to ask yourself is if the Chevy is too ugly for you. You should also ask if you’re interested in the MultiPro tailgate (the answer should be yes) and the carbon fiber bed (the answer should be no). 

In terms of the diesel curious, you need to ask yourself the questions above and if three mpg matters to you. Chevy’s truck makes 33 mpg highway, which is better than GMC’s truck by three mpg. The choice is yours. Personally, I’d take the GMC over the Chevy. The MultiPro tailgate option is worth it to me to pay a little more for the truck.

What’s the Verdict?

2020 GMC Sierra 1500 Duramax Diesel

The GMC 1500 Duramax diesel is a fantastic pickup truck. It’s powerful, attractive, comfortable, and easy to drive even if you’re towing a heavy trailer behind it. The model has some interior bugaboos, but otherwise, there’s very little to complain about. 

Is it the best full-size truck out there? Well, that depends on what you want and how you use your truck. However, I will say that it’s better than it has ever been before and the MultiPro tailgate and diesel engine helps make it pretty special. 


  • Base Price: $29,600 (for base non-diesel truck)
  • Price as Tested: Various models tested
  • Drive Type: 2×4 and 4×4
  • Engine: 3.0-liter turbo diesel straight-six
  • Transmission: 10-speed automatic
  • Power Output: 277 hp and 460 lb-ft of torque
  • EPA: 23 mpg city, 30 mpg highway, and 26 mpg combined
  • Optional Equipment: List not provided with vehicles driven
2020 GMC Sierra 1500 Duramax Diesel
The Breakdown
The GMC 1500 is its best when a Duramax Diesel is under the hood pumping out gobs of torque and sipping fuel. The truck is refined, smooth, enjoyable, and tough enough for any light-duty jobs
Reader Rating0 Votes
Smooth, quiet engine
Plenty of horsepower and torque
Sips fuel
Comfortable and easy to drive
Quality infotainment system
Interior materials should be better
Not really any better than Chevrolet’s truck