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2020 GMC Sierra 1500 AT4 Diesel Review: An Odd Couple

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Auto123 review the GMC Sierra AT4 Diesel.

When you start analyzing the product offering for a given pickup model, it sometimes feels like you're in a restaurant with a menu offering 150 meal choices.

The sheer variety of combinations available to the buyer can be dizzying. This a criticism, more just an observation. And frankly if companies are throwing everything but the kitchen sink into their offerings, it's because the demand is there.

You want variety? Consider this: counting the four types of bodywork offered, the two drive trains, the six levels of finish in the catalog and the five engines offered, that makes 74 different combinations that can be mixed and matched. And that’s before you get to the options packages.

That’s, shall we say, a lot.

Of course some are more popular than others, but still. And, fortunately, some combinations are not offered or possible. For example, there are no AT4 versions in two-wheel drive configuration. That's a no-brainer in its case, actually, given that the mandate of the AT4 is to tear it up off the beaten track. Anyways this brings us to the version we tested recently, one equipped with the diesel engine. A rarer combination, this...

First though, a few words about GMC.

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GMC Sierra 1500 AT4 Diesel, three-quarters rear
Photo: GMC
GMC Sierra 1500 AT4 Diesel, three-quarters rear

Moving on up
For a long time, GMC was known for doing little else but offering copies of Chevrolet models. That was a bit unfair, but it was its image, one historically not unrelated to the brand's dealers and their accessibility in certain parts of the continent. Long story. However, over time, many buyers have come identify with one or other of the brands. For example, in some of corners of North America, GMC models are more popular than Chevrolet models.

Things have evolved in recent years, and we've seen GMC stand out more and more. Not that the basic elements of their vehicles don’t remain identical to Chevy’s, but much effort has been put into creating distinctive designs and introducing their own, distinct variants and trims.

The Elevation and AT4 variants are good examples of this. As for the GMC Sierra, its sales continue to grow. In the United states, the model had its best year ever in 2020, with 253,014 units sold. In a pandemic year. Here at home, it also saw its sales grow in 2020 compared to 2019 (51,512 units versus 48,846).

And the momentum should carry through 2021, especially with the Hummer EV about to drop.

GMC Sierra 1500 AT4 Diesel, front
Photo: GMC
GMC Sierra 1500 AT4 Diesel, front

The AT4
GMC launched this version in January 2019, and it was a hit right from the start, quickly capturing 20 percent of Sierra orders. In addition to its enhanced off-road capabilities, its unique styling cues clearly appealed to many. These include a unique grille, two-inch raised frame, distinctive tires and front tie-down hooks in look-at-me red.

As for configurations, the Sierra AT4 can be delivered with two types of bodywork, the crew cab with the either a short or a regular bed. With the first case, three engine choices are possible, namely a 5.3-litre V8, a 6.2-litre V8 and the diesel engine. With the second, only the last two are applicable.

The diesel
Before the Volkswagen scandal broke in September 2015, diesel engines were quite common in many corners of the industry. But since that moment, it’s been a freefall. The one exception is the full-size pickup truck segment, simply because there interest is still strong. Diesel offers added value for some buyers who, for example, pile on the kilometers per ton carried. Some just like to tow with a diesel-powered engine.

And there's the fuel-consumption consideration, of course. My week-long test drive of the Sierra AT4 Diesel resulted in a rating of 10.1L/100 km – pretty darn good for a vehicle of this size. Of course, buyers will do well to also consider the higher maintenance costs, as well as the expected longer life expectancy of a diesel powertrain when making their calculations and choices.

On that note, I defer to their needs and preferences. An AT4/Diesel combination may seem like a bad choice for some, while it could be the perfect match for others.

GMC Sierra 1500 AT4 Diesel, profile
Photo: GMC
GMC Sierra 1500 AT4 Diesel, profile

The drive
Behind the wheel, the presence of the diesel engine doesn't change the vehicle's behavior in any way, except that during harder accelerations, you can feel the difference between the hp of a V8 engine and the torque of a diesel engine. The model's inline-6 takes advantage of turbocharging to deliver 277 hp and 460 lb-ft of torque, and a towing capacity of 9,300 lb. A 10-speed automatic transmission connects the engine to the wheels.

For the rest, the Sierra AT4 delivers an experience marked by solidity and ruggedness. And of course, there’s the sense of invincibility as the truck reinforces your already-dominant position on the road due to its elevated stance.

As for the interior environment, it is, as you’d expect, characterized by tons of space, but also by functionality. We do continue to look forward to the day when GMC will seriously revamp its interior presentation to enhance appearance and quality. That there is the Sierra's main weakness, especially when you look at what Ford and Ram are doing.

GMC Sierra AT4 Diesel, interior
Photo: GMC
GMC Sierra AT4 Diesel, interior

The equipment includes all the expected and required connectivity features and amenities (heated seats, for example), but as mentioned you throw in different packages that enrich the offering. Our tester included the AT4 CarbonPro package, a $4,790 deal that brings a carbon-fibre composite solution to the body, as well as a sliding rear window, navigation, Bose audio system, wireless cell phone charging, 18-inch Goodyear Wrangler DuraTrac tires and a driver alert package.

The $2,520 Technology package also came with our tester. It features an HD peripheral camera with two angles for the trailer, digital rearview mirror, head-up display and 8-inch driver information screen on the instrument cluster.

A number of other packages are offered, each with some unique features. Note, however, that some items may be found in more than one bundle, some more expensive than others. The buyer has a lot of choosing to do.

GMC Sierra AT4 Diesel, second row
Photo: GMC
GMC Sierra AT4 Diesel, second row

The base price of our model was $63,098, but as tested it ran to $75,738 before shipping and preparation costs ($1,900). Yes, ouch in both cases. By the way, the choice of diesel engine costs you $3,245 extra.

And speaking of math, here’s a figure for you: GMC estimates total highway range on a full tank at 999.46 km with this model. Someone will have to explain to me how they arrived at such a precise figure. Could they not just have put 1000 km?

Notwithstanding the price, which likely won’t dissuade buyers of this type of vehicle anyways (they can always lease, or resell quickly), and aside from the diesel engine that doesn't seem to fit with this variant, the GMC Sierra AT4 is a super able pickup that’s easy to fall in love with. You have a good time behind the wheel and you’ll appreciate its practicality and go-anywhere ruggedness.

Another way to look at the price: this is a model you could easily hold onto for 20 years or more. Something to think about...

GMC Sierra 1500 AT4 Diesel, three-quarters front
Photo: GMC
GMC Sierra 1500 AT4 Diesel, three-quarters front

We like

Nice styling
Overall pleasant drive
Reasonable fuel consumption
Wide choice of versions
Multifunction tailgate

We don't like

The price
Interior presentation needs refreshing
Maintenance regimen that allows for no corner-cutting