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First Drive of the 2020 GMC Sierra HD AT4: For the Substance… and the Style

Jackson Hole, WY – The automotive industry as a whole has been roiled by uncertainty in the last few months. Sales are on the decline in several segments, traditional car segments are getting turned upside down and terms like electric mobility and zero emissions are on everyone’s lips.

The truck segments haven’t escaped the upheaval: Not only is Elon Musk committed to producing a Tesla pickup, but new players plan to crash the party as well. Then there are Ford (in alliance with Rivian) and GM, both of which have clearly indicated their intention to add fully electric trucks to their lineups.

Up in the rarified air of the big-guy workhorses, though, it remains, for now, business as usual. HD, or Heavy Duty, trucks are as yet unaffected by the growing popularity of electrified vehicles across the industry - protected in a sense by their much-superior capabilities.

At present, there are no evident short-term plans among Ford, Ram or even General Motors to introduce electric motors into any of their HD products.

Photo: V.Aubé

Like its cousin at Chevrolet, the 2020 GM Sierra HD has been renewed from front to back for the next model-year. Not only that, but the truck designed first and foremost for big works is getting an AT4 variant, as GM continues to roll out the special version across its line of GMC trucks.

The manufacturer’s Canadian division invited a few Canuck journalists to come and meet the new 2020 Sierra HD in the U.S. state of Wyoming, in and around Jackson Hole to be precise. Here are the impressions I came away with after a day of happy trucking.

A totally new Sierra
The folks at GMC didn’t hold back with this new generation of the HD pickup. Everything is new – or almost, I should say, since the roof is taken from the GMC Sierra 1500 introduced last year. For the rest, the big pickup is utterly different from the previous generation, which, you might recall, used the same cabin for the 1500 and bigger models.

Photo: V.Aubé

No longer. The engineers wanted to deliver more space to passengers climbing aboard these pickups built to tow much bigger weights. The new 2020 GMC Sierra HD is also longer and taller and features a longer wheelbase. Surprisingly, despite the fact that the Sierra is taller up front, the bed is actually lower to the ground, by one inch. This adjustment was necessary to make loading cargo onto the truck easier; it also makes it easier to attach a fifth-wheel hitch.

The AT4 version comes with a massive black front grille, with the three G-M-C letters splayed dead-centre across the front. There are red tie-hooks in front, and the truck rides on exclusive black and chrome wheels. The wing contours are also more rugged in comparison with those of the Sierra 1500. For the rest, the GMC Sierra HD AT4 is just as massive and dominant on the road as the other Sierra HDs.

An office on wheels
With more usable space on board – we tested only the bigger-cabin versions – the Sierra HD is a very inviting place, even if climbing aboard requires a little, well, climbing. Fortunately there’s the practical footboard as well as a handle on the A pillar.

Photo: V.Aubé

Once seated, it’s easy to find the right driving position thanks to the power-adjustable seat and the adjustable steering column. There’s no shortage of space in the first row, and it’s just as good behind, where the bench can be folded up to allow for protecting larger objects from the elements.  

You could find fault with the relatively small size of the infotainment system’s screen; the 8-inch screen does look a little puny compared to the Ram HD’s available 12-inch screen. But hey, a screen is not what a truck is all about!

The dashboard is fairly traditionally arranged, with a multitude of buttons clustered in the centre as well as on the left side, some of which are for playing with the drivetrain configuration of the truck. And since this is a General Motors product, the gear lever is still mounted on the steering column, freeing up a lot of space on the central console. This allows for the presence of an induction-charging pad for smartphones, USB ports, two cup-holders and a central storage bin able to swallow up a 13-inch laptop.

Photo: V.Aubé

The ultimate test: At the wheel of a beast
Over and beyond the appearance, the comfort features and all the other functions and doodads the GMC Sierra HD comes with, the litmus test is how it is to drive the thing. Is it good or is it not?

The manufacturer is well aware that most buyers of an HD truck will use it to pull stuff, at least occasionally. But a good work truck also has to be able to transport a heavy load in its bed. Our road test thus started with a truck equipped with a new 6.6L V8 gas engine, good for 401 hp and a respectable 467 lb-ft of torque. The 2020 Sierra HD with that unit is wedded to a 6-speed automatic transmission, while the driver gets to choose the configuration of the drivetrain: 2WD, 4WD, slow 4WD or even Auto, which manages the configuration according to need without human intervention.

We set out with 2,800 lb worth of tree trunks in the bed, and while the Sierra HD AT4 certainly surpassed the official fuel consumption rating during the exercise, when it came to accelerations or passing manoeuvres, it showed no signs of labouring under the strain.

Photo: V.Aubé

We also got to test out a double-wheeled 3500 HD truck, to which was attached a trailer full of tailgates belonging to competitors’ trucks (this in connection with a marketing campaign GMC designed for its MultiPro tailgate) and metal sheets.

With a towing capacity of 40,000 lb (43,500 lb with a regular cab), the pickup drove like it had nothing bigger than a fly on its tail. For sure, with so much extra weight, accelerations are less electrifying and merging into highway traffic and braking both require more planning, but that’s so for all heavy-duty trucks.

Our day of happy trucking wrapped up with a stint at the wheel of the GMC Sierra HD AT4 equipped with a 6.6L turbodiesel V8, as we pulled a load straight into downtown Jackson. This unit generates 445 hp and mammoth torque of 910 lb-ft, thanks in part to a 10-speed automatic transmission taken from the catalogue of supplier Allison, new for 2020.

Photo: V.Aubé
Photo: V.Aubé

Though we didn’t get to try the pickup free of any load attached, this first encounter at least allowed to see how well-suited this powertrain is for big jobs. For those who need to pull heavy loads, the diesel option is the obvious first choice, even if it costs an extra $11,195 to get it.

I should also mention that the “transparent” camera function is really practical, especially for a towing novice like me. Being able to remove this huge mass from one’s line of sight – at least when you use the central console screen – makes a lot easier to pass on the highway or park the vehicle.

The 2020 GMC Sierra HD AT4 is such a versatile vehicle that it’s hard to cover everything in a single review. Like its competitors, this American truck can be had in a multitude of different configurations to fit varied needs of its customers. The renewed pair of engines is very well-adapted to the truck’s chassis, and the model edges closer to perfection than ever before.  

Of course, you have to be ready to swallow the minimum of $72,098 required to get yourself one of these trucks in twin cab AT4 version. The same version but with the Duramax diesel engine costs $92,113 or more. These are huge sums, but if you’re going to want to be able to tow your house, for example, you need the right gear to do it!

Photo: V.Aubé