2020’s best diesel pickup: The 2020 GMC Sierra Diesel

2020 GMC Sierra diesel

GM Canada provided a 2020 GMC Sierra diesel with a full tank of fuel for the purposes of this road test.

2020 GMC Sierra diesel

Rap sheet

  • 2020 GMC Sierra Diesel diesel Elevation trim
  • 3.0L six-cylinder turbo diesel engine
  • 10-speed automatic transmission
  • 277 hp and 460 torque
  • 7,200 lb GVWR, up to 9,000 pounds towing.
  • 8-inch touchscreen, Android Auto®, Apple CarPlay™, Bose® audio system.
  • Four-door, five-passenger seating.

Truck people are a loyal bunch, but the 2020 GMC Sierra diesel comes ready to challenge the beliefs of the life-long brand loyalist. For this truck nut, I have have typically fallen into the F-150 camp. Ram was the first to bring out a light-duty diesel in 2014 with their EcoDiesel, and it took Ford four years until their own 3.0L V6 became available. GMC is the last of the big Detroit three to put a mid-duty diesel into their half-ton truck line up. In the opinion of this typical Ford-follower, they saved the best for last.

Our tester was the new-for-2020 Elevation crew-cab setup with the standard 6.5-foot box. The Elevation trim slots the Sierra into the pricing sweet-spot with some of the most popular F-150 and Ram 1500 models. You’ll find most of your wish-list at the mid-level Elevation trim. Well-priced feature packages help round out what you want. As-equipped, our 2020 GMC Sierra tester is pretty much exactly how I’d spec a half-ton if it was my money on the line.

The meat and potatoes

Trucks at their hearts are vehicles of utility. There’s an irony in that most of them are bought by folks who daily them. Not to say they shouldn’t be daily driven, that’s just what we did. The 2020 GMC Sierra does well balancing the capability of a half-ton with the ride of a unibody SUV. Truck fans will still get the bulky ride that you expect, but it’s not harsh enough to be offputting to all your passengers, either. In fact, the 2020 GMC Sierra excels as an around-town vehicle, and that has a lot to do with the diesel (more on this later).

If you’re looking at this truck purely on paper, the 2020 GMC Sierra might seem like a losing contender. Of the big three diesel offerings, it has the lowest total and combined vehicle (GVWR, GCWR) weight maximums. In real life, that doesn’t mean a thing. As for those numbers, our test truck has a 7,200 lb GVWR and 15,000 GCWR. GMC gives it up to 9,000 pounds of towing capacity.

Rubber hitting the road

In a fortunate turn of events, we took the 2020 GMC Sierra diesel loan on the same week I tore down and built a fence. At the time of publication, there was a province-wide shortage of pressure-treated wood. Meaning, the truck got a hard workout driving from hardware store to hardware store. It’s a great real-life test to see how the 2020 GMC Sierra diesel performs as a practical truck, doing the jobs it’s meant to do.

Despite what it says on paper, the truck never lets this show. It was at the limit of payload capacity several times, hauling bags of cement, lumber, and construction rubble. At one point, we actually had it loaded to 75 kg (165 lbs) over GVWR. However, the frame or the engine didn’t seem to notice the weight. The ride was more bouncy than empty, but even still the Sierra handled and rode like a champ.

You’ll find then that the 2020 GMC Sierra diesel is every bit as capable as a payload and towing truck as the competitors. It’s more than enough for even the most ambitious urban construction work. Will it pull a behemoth fifth-wheel trailer? Not even close. But that’s not what a half-ton truck is for.

Glamor shots

After a week of hard work and hauling, the 2020 GMC Sierra diesel got a bath. This was a beautiful truck to have in the driveway. It’s a modern design that isn’t loud or obnoxious either. On the inside, everything is laid out cleanly and simply. There’s nothing here to wow you, but it’s also not a pain. It’s comfortable, modern, and practical; everything a truck interior should be.

Take a look for yourself.

2020 GMC Sierra Gallery

Image 1 of 204

The diesel advantage

What makes this 2020 GMC Sierra diesel special is the diesel engine. Arguably, the best use of a diesel engine is in a half-ton pickup truck. It’s not a surprise to see them in vehicles from the big three Detroit companies. But what separates this diesel from Ford and Chevy? Simple, all the cylinders are in a line. There’s nothing wrong with a V6, but the efficiency and smoothness of the inline-six take it to the next level.

Put out of your mind the images of large, dirty, rough rumbling diesel engines you may have driven in the past. Even under heavy loads or aggressive acceleration, the 2020 GMC Sierra diesel is silky smooth. The 10-speed automatic is so fast and smooth; it almost feels like a CVT. You don’t need pumped-in audio here, why cover up the beautiful sound of a diesel? Even my kids enjoyed driving around the neighborhood, just to hear the engine sounds.

Best of all, this truck is efficient. While the price of diesel at the pumps goes up and down, it’s still easy to see the benefits over the gas fuel engines. The numbers our 2020 GMC Sierra diesel got throughout the test were eyebrow-raising. Over a 160 km (100 miles) freeway trip, the 2020 GMC Sierra diesel netted 7.9 L/100 km (35.8 mpg). Overall, including heavy hauling, our final road test average came in at 9.2 L/100 km (30.7 mpg). That’s the same kind of mileage you’d expect from a crossover, maybe a sedan. A Crew-cab pickup? It’s a brave diesel new world we live in.

The best diesel half-ton in 2020

That heading says it all. For the vast majority of half-ton truck buyers, the 2020 GMC Sierra diesel, in this Elevation trim, is going to hit the sweet spot. You get daily mileage numbers that make much smaller vehicles blush. The diesel drivetrain is butter smooth, to the envy of other diesel half-tons on the market. And, unless your towing massive things, the smaller capability numbers won’t be noticed when you really need to make the truck work.

At the end of the day, the 2020 GMC Sierra diesel has made me question my F150 loyalty card. That alone says everything.

Dan Croutch
the authorDan Croutch
Dan is a freelance automotive and technology writer. He enjoys all things pickup trucks, classic cars, and minivans (really). The intersection of vehicles and technology fascinate him.