2020 GMC Sierra 1500 AT4 Duramax: 2020 Pickup Truck of the Year Contender
A Perfectly Cromulent Pickup
Last year, we found a lot to like about the 2019 GMC Sierra 1500 AT4. Equipped with a brawny 6.2L V-8 and 10-speed automatic, it featured excellent styling, Olympic-sprinter reflexes, and a cushy highway ride. However, it was let down by a relative paucity of luxury features and uncontrolled suspension motions off-road. Well, we're happy to report that for 2020, many of our complaints about the AT4 have been addressed, and what's more, GMC now offers the truck with a stellar 3.0L Duramax I-6 diesel.
That Duramax is a huge reason why so many of us liked this truck. We've written it a thousand times already, but I-6s make better diesel engines (better engines period) than many other configurations thanks to their inherent balance and smooth torque delivery. To package the lengthy diesel under the hood of the -ton GMC required some clever witchcraft, like putting the camshaft's drivetrain on the back of the engine, rather than the front. But it all fits, and GM engineers have told us with a wink that Chevy/GMC pickups won't be the only place we'll find this diesel.
In towing, hauling, and regular use, the diesel is a perfect companion. It hustles down the dragstrip with acceptable speed, and turbo lag is all but nonexistent. It's also incredibly efficient, putting down the occasional 30-mpg stint on the open road. Those long freeway stretches also revealed the truck's impressively quiet and smooth ride, even over rough pavement.
Saddled with some weight, the engine and 10-speed transmission work well together, and the suspension doesn't lose all composure at the sight of a heavy payload. However, some of us wished the truck's tow/haul mode would provide more aggressive downshifts—we had to use the service brakes more frequently than we'd have liked when descending grades with a trailer in tow.
What's more, while we found last year's AT4 test subject to be a bit too bouncy in fast off-road driving, the new truck is substantially improved. GMC hasn't made much hay about it, but the 2020 model's revised suspension should be front-page news for the company. Somehow, whatever minor tweaks they made transformed the truck into something that can go toe to toe with a Ram 1500 Rebel. In fact, comparing diesel to diesel, we found ourselves liking the AT4 more since the front end's damping feels appropriate for the engine weight. We wish GM (and Ram, for that matter) would follow Ford in offering a selectable rear differential lock, but until then, the automatically locking rear diff in the AT4 works just fine. There's plenty of suspension travel and traction for a wide variety of off-roading situations.
Holding this particular truck back from being a true world-beater are two things: its interior and high price. We've spent a lot of time complaining about the modern GM pickups' interiors, so we won't harp too much. But suffice it to say, in their judging, our editors scored the relatively ancient Super Duty pickups more charitably than the 1500 AT4. Our tester also cost $10,000 more than the Rebel to which we often compared it, and in fairness it was a full-length crew cab, versus the Ram's truncated Quad Cab. But it still didn't feel like $10,000 worth of more truck, in spite of its comprehensive suite of driver aids and safety features (for 2020, GMC added adaptive cruise control to the roster).
But if you'll check the scoresheet, you'll note that even in Sixth Place, the GMC is only 2.8 points behind our winner and less than one point away from being a podium finisher. That's a testament to two things: how excellent almost every modern truck is and how much we loved the 2020 Sierra 1500 AT4 Duramax's fabulous engine and excellent suspension.