• Review 2020 GMC Sierra AT4 Duramax

Review: 2020 GMC Sierra AT4 Duramax

Great engine, great utility, ride meant for dirt

Evan Williams By: Evan Williams October 6, 2020

Fuel economy is finally starting to become a bit of an issue for the nearly half of buyers picking a full-size truck every year (or at least it was before gas dropped back below a dollar at the start of the year). The perfect truck might not use any gas at all, though this GMC Sierra 1500 is probably not exactly what those words brought to mind.

Not an electric truck, though the market is just years away from filling up with those (isn’t it always?), this one’s a diesel. A fuel-sipping, smoke-free, torque monster, it has the chance to make the likes of GM’s own 6.2L V8 (and the 3.5L twin-turbo V6 of the gorilla in the segment) obsolete.

This particular truck brings a whole lot of GMC’s latest along with it. First, it’s GMC’s new AT4 trim that tries to marry Denali luxury – with less flash so it better fits in at the worksite or office – with increased off-road capability and the slight lift that was going to be added once the ink was dry on the contract anyway. It also gets GMC’s fancy Multi-Pro tailgate that goes beyond gimmick to add usability as big as the box, which happens to be carbon fibre to shave weight and to be almost indestructible. Lastly, this one’s a new 3.0L inline-six Duramax diesel married to a 10-speed automatic.

That 277 hp, 460 lb-ft new engine is a $3,245 option over the 355 hp 5.3L V8 and $350 more than the 420 hp 6.2L V8. And yes, it’ll require you to head over to the slightly smellier diesel pump. But it offers 3.2L/100 km combined better than the 5.3L AT4 on paper, and in the real world this truck managed low 9s in a mix of high-speed hilly back road (think 90 km/h and loads of braking and acceleration) and city driving, with that two-inch lift and chunky mud-terrain tires. That’s about half the fuel consumption of any gas full-sizer I’ve driven, and they would normally get a more fuel-sipping drive route.

Review 2020 GMC Sierra AT4 Duramax

None of that would matter if this was a traditional smoky, rattly diesel, but it’s not. As smooth as any gas truck, with an even smoother 10-speed auto and just a hint of diesel clatter that’s more welcome than intrusive, this might just be the best driveline in any current pickup. With push-start, there’s no watching for a glow plug light, the truck does everything itself.

Which makes it a shame that the lift and off-road suspension tuning (and those tires) don’t do the ride any favours. Yes, if you spend your time on dirt roads doing your best Petter Solberg impression (make that Pete Solberg?) then the ride is wonderfully soft, but on the highway it’s jiggly. The ride is as bumpy on smooth pavement as it is on bad roads because the suspension seems to always be looking for something to do. If you don’t need the M/T rubber and stick to pavement, then don’t bother with AT4, get a loaded up SLT or deal with the extra flash of Denali.

GMC has loaded this truck with cameras, including optional trailer-attached cams (15 views total), and when it comes to manoeuvring and parking this barge, they’re extremely helpful. They’re GMC’s party trick (shared with Chevrolet), and the ability to see “through” your trailer could be a lifesaver. Too bad you can’t use the trailer cam and the NAV system at the same time, the way you’d want downtown. GMC’s standard (and only) 8-inch infotainment system is super smooth, and one of the quickest and most user-friendly around (with easy shortcuts to map, music, and home screens), but it doesn’t have the real-estate Ram’s 12-incher offers so you’re limited to one or the other. The big, colour, head-up display will show directions, but it’s not the same as a map. Apple CarPlay and Android Auto are standard, and there are USB A and C ports, but wireless charging is extra.

The screen sits in a massive expanse of plastic, and while all of the buttons are truck-friendly, meaning easy to use with work gloves on, the plastic surrounding them feels low rent for a truck sneaking up on $80,000. Especially the (optional) seat heat and ventilation buttons which feel one hard poke away from disappearing into the abyss inside the dash. Massive headroom and a rear-seat with more hidden cubbies than seats and legroom that rivals a stretch limo makes this cabin an otherwise exceptional space to spend time. Power outlets front and rear, plus minivan quantities of cup holder add to the family truckster appeal.

Review 2020 GMC Sierra AT4 Duramax

GMC’s list of driver aids is lengthy, but most fall to the options list. Even on this high-spec trim, a camera mirror and hitch-view are standard, but getting parking sensors, lane change and blind-spot alert, rear cross traffic, and adaptive cruise will require a couple of option bundles and more than a couple of thousand dollars. Towing for the diesel is a few thousand pounds lighter than the gas options thanks to the weight of the engine and GM wanting max economy, but still within a hair of 10,000 lbs.

This is an impressive package, the optional CarbonPro bed and MultiPro tailgate add meaningful utility, and I’ve already fawned over the diesel engine. GMC also knows that plenty of buyers want meaty rubber and a slight lift, so they’ve made it available off the lot. Driving a rig like this, it’s easy to see why the full-size truck is the new family sedan, but unless you really do plan on spending extended time in the dirt keep the diesel and the tailgate but drop the off-road bits. You’ll be more comfortable, and your wallet will probably be happier.

The vehicle was provided to the writer by the automaker. Content and vehicle evaluations were not subject to approval.

2020 GMC Sierra 1500 Pickup Crew Cab 4×4

BODY STYLE: Four-door crew cab short bed pickup
DRIVE METHOD: 4×4 with 10-speed automatic
ENGINE: 3L inline-six turbo-diesel (277 hp, 460 lb-ft)
FUEL ECONOMY: Fuel Economy (diesel) 10.5/9.1/9.9 L / 100 km city / highway / combined
TWO RATING: 4,445 kg
PRICE: MSRP $63,098, $75,738 as tested
WEBSITE: www.gmccanada.ca