2020 GMC Sierra 2500HD AT4 Duramax: 2020 Pickup Truck of the Year Contender - TruckTrend Network

It's no secret we're fans of GMC pickups. In fact, up until now, GMC has been the only repeat winner of our coveted Pickup Truck of the Year award (2016 and 2018). So with the all-new Sierras (1500 in 2019 and 2500/3500 in 2020), we had high hopes for delivering a third Billet Piston trophy. We weren't shocked when the Sierra 2500HD AT4 came really close to nabbing the prize this year.

Photo 2/15 | 2020 Gmc Sierra 2500 At4 Duramax Drive

The biggest difference between the GMC Sierra 2500HD and Chevrolet Silverado 2500HD is exterior styling. Unlike the light-duty trucks, these share a bit more sheetmetal in common. However, front and rear end design is totally unique to each brand. And, unsurprisingly, our judges heavily favor the new GMC styling over that of its cousin. Add in the fact that our tester came to us outfitted in AT4 trim, which provides body-color accents and those infamous red tow hooks, and it's easy to see how the Sierra garnered more points.

Under the hood was GM's carryover L5P Duramax diesel engine. While the Duramax has less torque than the competition on paper, it's difficult to tell in the real world. Thanks to the new 10-speed Allison 10L1000 transmission, the Sierra uses its 445 hp and 910 lb-ft of torque to tow and haul just as good, if not better, than HDs with four-figure torque ratings. The truck's selectable exhaust brake works exceptionally well at slowing even the heaviest of loads, and the 10-speed Allison holds gears well in tow/haul mode. Aiding in towing even further is the same suite of cameras and 15 camera views that were outfitted to the Silverado 2500HD LTZ.

Photo 3/15 | 2020 Gmc Sierra 2500 At4 Duramax Mud

Most of our judges appreciated the truck's exterior styling, enjoying the body-color accents that come as part of the AT4 package, along with the unique 20-inch wheels. The interior was well appointed as well, with custom leather-trimmed AT4 seating surfaces, a multi-color head-up display, rear camera mirror, and every safety system currently offered by GM on an HD pickup.

This interior was also likely the reason the Sierra 2500HD AT4 fell short of the top podium spot. Dash layout is the same as the light-duty 1500 pickups and nearly universally loathed. On their own, the new interior and dash aren't terrible, but when compared with that of the competition, it's easy to see just how short GM fell in its attempt at updating. The Bose audio system is OK, but not great, and the same can be said for the truck's 8-inch IntelliLink infotainment system. And while the design of the seating surfaces was pleasing to the eye, their firmness was less than appreciated by many of our judges' posteriors.

Photo 4/15 | 2020 Gmc Sierra 2500 At4 Duramax Off Road

Also confusing to our staff was the lack of off-road content provided by the AT4 package. On the Sierra 1500, checking the box for AT4 brings with it a 2-inch lift, 18-inch wheels, Goodyear DuraTrac off-road tires, and unique Rancho shocks. The HD trucks get none of this. In fact, AT4 is little more than an appearance package pasted on the classic Z71. This isn't to say it's at all incompetent in the dirt, but it did befuddle several of our judges.

Off-road, the truck performed OK. The more all-weather-oriented tires provided little grip and the 20-inch wheels left us worrying about sidewall punctures. What the truck did have was an automatic locking rear differential, the same G80 GM has used for decades. While the differential works to provide traction when the rear tires are spinning quickly, it does little to help when going slow. We'd love to see the AT4 package include a selectable locking differential in the future.

Photo 5/15 | 2020 Gmc Sierra 2500 At4 Duramax Interior

Photo 6/15 | 2020 Gmc Sierra 2500 At4 Duramax Interior Seats

At the end of the week of testing, the GMC Sierra 2500HD AT4 scored well enough in each category to find itself less than half a point from nabbing the trophy. The 2500HD AT4 was the test favorite of many judges, and a few simple improvements would make all the difference.

WE LIKE: Clean exterior design, impressive drivetrain, advanced technology.
WE DON'T LIKE: Poor interior styling, lack of off-road content.

2020 GMC Sierra 25000HD AT4

Base Price: $69,185
Price As Tested: $76,960
EPA Fuel Econ (City/HWY/Comb): N/A
Engine: 6.6L V-8 turbodiesel
Horsepower: 445 @ 2,800 rpm
Torque: 910 lb-ft @ 1,600 rpm
Transmission: 10-speed automatic
Accel 0-60 MPH: 8.03 seconds
Quarter-Mile: 16.35 seconds
Braking 60-0 MPH: 148.34 feet
Accel 0-60 (Payload): 9.12 seconds
Quarter-Mile (Payload): 17.05 seconds
Braking 60-0 MPH (Payload): 142.84 feet
Accel 0-60 (Towing): 16.24 seconds
Quarter-Mile (Towing): 21.35 seconds
Weight: 8,081 pounds
Tested Fuel Econ (Average/Best): 14.25 mpg/16.08 mpg
*2,800 pounds of payload **10,000-pound trailer weight