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The GMC Sierra AT4 Is a Surprisingly Agile Grunt of a Truck

The AT4 distinguishes itself with unique styling details, off-road shocks and tires, a locking rear differential, and a factory-installed two-inch suspension lift.

The AT4 is GMC’s premium off-road trim of the Sierra 1500 full-sized pickup. It distinguishes itself with unique styling details, off-road shocks and tires, a locking rear differential, and a factory-installed two-inch suspension lift.

Buy Now: $53,200 (base MSRP); $64,500 (as tested)

The Good: Robust engine. Quality transmission. Useful, intuitive tech.

Who It’s For: The affluent GM-inclined truck buyer who wants to hit a (very) wide open trail or appear like he or she is a person who may do so.

Watch Out For: Sheer enormity. Poor fuel economy. Usability with two-inch lift.

Alternatives: Other off-road oriented premium full-sized trucks in this general price range include:

2019 Ford Raptor ($52,855, base)

2019 Ram 1500 Rebel ($44,940, base)

2019 Chevrolet Silverado LT 1500 Trail Boss ($49,795, base)


Review: Driving a full-sized pickup in its natural environs on a product launch is one thing. Having a full-sized pickup invade your everyday life for a week is quite another. Even in large car-friendly Detroit, the GMC Sierra AT4 felt like a vehicle smuggled out from Brobdingnag. It’s a mammoth truck meant for bigger people, wider roads, more generous parking spaces, and larger turning radii.

The AT4 is the Sierra’s premium off-road trim. It’s GMC’s answer to Ford’s F-150 Raptor. The big changes are similar to the Silverado Trail Boss. It has a two-inch factory lift, Rancho shocks, and aggressive off-road tires. It has more than 10 inches of ground clearance. A low-speed terrain cam offers a fine view of the obstacles you can’t see or feel organically.

When there’s room, the AT4 does offer is an engaging drive. The 6.2-liter V8, producing 420hp and 460lb-ft of torque, is formidable. It’s paired with a spot-on 10-speed automatic transmission. The AT4 handles nimbly. The steering, for a truck, is precise. Its propensity to pick up speed quickly during a highway overtake can be alarming. I would opt for the upgraded Catback exhaust. A 6.2-liter V8 seems pointless if it’s going to sound civilized.

GM uses tech in its trucks well. Features are useful. Interfaces are intuitive. Camera angles and seat buzzers navigate you out of tight spots, which happen almost every time you park. The Multi-Pro tailgate gets too much hype since it’s one of the few distinguishing features between the full-sized flagship trucks. But, it’s well thought out. The dashboard offered every type of wired port I can think of as well as wireless charging.

I had a mixed reaction to the styling. GMC’s obsession with bold vertical stance is not my cup of Earl Grey, though I may be in the minority there. The body color grille and blacked out chrome offered some appreciated understatement compared to the blinged out Denali. The interior was clean and spacious. But, it also felt dated and too reminiscent of the Silverado for what amounts to a $60,000-plus luxury car. When you see what Mercedes did for half the price with the A-Class, GM could have offered more.

While the off-road tires do not affect the driving dynamics noticeably, the two-inch lift does impact the truck’s usability. The floor is two inches higher. I’m 5’11” and would have had to entire via flying leap without the step. The car seat for my 30-pound toddler was two inches higher. The workbench on the tailgate was two inches higher and too high for me. The roof is two inches higher, which (very) nearly caused me to scrape the roof in a low parking garage.

As you would expect, a full-sized truck with a 6.2L V8 won’t be resolving the climate crisis. EPA numbers for my tester were 15/19/17mpg. Per that estimate, the AT4 will quaff an extra $1250 per year of fuel over the average new car. I only averaged 13.3 mpg going about my business in cold-ish weather. It’s not an efficient way to get around town.

gmc sierra at4

The AT4 is large, quick, and capable. More of a surprisingly agile offensive lineman than rookie year Shaq. It’s not as excessive and purpose-built of an off-roader as the Raptor. But, the AT4 is more than a mere styling gambit, even if that is its role in the Sierra lineup.

Verdict: The athletic and versatile AT4 trim won’t disappoint Sierra buyers. This truck is potent on the tarmac and capable when you leave it. The AT4 is missing the Raptor’s immoderate pizzazz, however, and feels far too gigantic to be an off-road toy. Dedicated off-roaders may want to move down a class, drop some weight, save about $20,000, and buy a Tacoma, Gladiator, or Colorado ZR2.

What Others Are Saying:

“What was noticeable, however, was that other motorists could tell this truck was special: More than once I spotted other Sierra or Chevy Silverado owners craning their necks and doing a double-take at the AT4.” – Jake Holmes, Roadshow

“Let’s say it right now: no vehicle stretching six metres from stem to stern, and on a wheelbase pushing four metres, can claim ultimate go-anywhere talent. In some off-road scenarios, a full-size pickup is Just. Too. Big.” – Jeremy Sinke, The Globe and Mail

“On the road, the AT4’s extra height doesn’t negate the new Sierra’s surprisingly lithe feel. Maybe “lithe” is too strong a term, but comparatively speaking for a full-size truck, it changes direction with poise and doesn’t overwhelm. A rather small steering wheel helps in this regard, as does the improved rack it’s connected to for 2019. ” – James Riswick, Autoblog

2019 GMC Sierra 1500 Crew Cab 4WD AT4 Key Specs

Powertrain: 6.2-liter V8; 10-speed automatic; four-wheel-drive
Horsepower: 420 hp
Torque: 460lb-ft
0-60: 5.8 seconds (Motor Trend)
Curb Weight: 5,400 lbs
Fuel Economy: 15/19/17 mpg combined

Buy Now: $53,200 (base MSRP); $64,500 (as tested)

GMC hosted us and provided this product for review.

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