In the beginning of the day the vehicles are spotless, their 18-inch wheels, dark-finish exterior trim and crimson tow hooks on outstanding show. A few hours later they’re filthy, splattered with dust and dripping muddy water. That’s, in spite of everything, precisely how the 2019 GMC Sierra AT4 is supposed for use. It is a bundle designed for Sierra consumers who plan to take their truck off-roading, and a romp across the trails at Eaton’s proving grounds in Marshall, Michigan, reveals that the AT4 is greater than as much as the duty.
Eaton opened its gates to a gaggle of journalists driving GMC Sierras as a result of the provider manufactures the AT4’s locking rear differential. The corporate’s 636-acre proving floor has loads of house for romping round within the mud and dust, in addition to varied paved amenities for testing all the pieces from on a regular basis automobiles to Class Eight vehicles. However as you’ll inform from our video, the “proving grounds” felt extra like “playground” on my go to.
Prepared for the dust
AT4 is a brand new trim degree for the 2019 GMC Sierra that amps up its off-pavement talents. The truck receives a 2-inch suspension carry complemented by Rancho shock absorbers, the aforementioned Eaton G80 locking diff and both 18- or 20-inch wheels, the previous of which may be outfitted with Goodyear Wrangler Duratrac mud-terrain tires. In different phrases, all of the varieties of upgrades off-roaders would possibly need in an effort to take their truck out into the woods.
The AT4 comes commonplace with a 5.Three-liter V8, which is rated for 355 horsepower and 385 pound-feet of torque and is mated to an eight-speed computerized transmission. Consumers can improve to a 6.2-liter V8 with 420 hp, 460 lb-ft and a 10-speed computerized. And AT4 consumers can even go for a efficiency air consumption and exhaust package that’ll unlock much more energy: an additional 12 hp and 6 lb-ft on the 5.Three V8 and 15 hp/9 lb-ft for the 6.2 V8. However you will actually need that possibility for the boisterous, rumbly sound it produces below heavy throttle.
Different options embrace hill descent management, commonplace four-wheel drive, dark-finish exterior trim, a body-color grille and bumper, vertical-oriented crimson restoration hooks, “Kalahari” seat inserts and rubber ground mats. The AT4 can be considered one of solely two trim ranges (the opposite being the glitzy Denali) that can be supplied with the Sierra’s elective CarbonPro carbon-fiber mattress. GMC has mentioned it would roll out the AT4 therapy to different fashions in its lineup, although we’ll have to attend to see what the subsequent mannequin can be. (The Canyon midsize pickup truck appears a possible candidate.)
Suspension upgrades and new tires make the AT4 higher suited to journeys away from the suburbs.
No roads, no drawback
I began out by tackling a handful of obstacles that Eaton makes use of particularly to check car functionality. A giant ditch, as an illustration, is meant to flex a truck’s body and in addition requires beneficiant strategy and departure angles in order to not scrape physique elements. I simply drove the AT4 out and in of the ditch with out subject, the truck’s 2-inch carry serving to and the immense gearing benefit of the four-wheel-drive system’s low vary making ascending the opposite facet a breeze.
Blasting by means of a deep mud pit was straightforward too. The Eaton differential got here in helpful right here. It self-locks the rear axle as quickly as one wheel spins 100 rpm quicker than the opposite — which, given how a lot the truck slipped and slid and kicked up mud, will need to have been just about immediately. A “low traction” warning flashed on the head-up show however with out a lot fuss, the truck powered out the opposite facet. (One other journalist did get caught within the mud pit and needed to be towed out by a Caterpillar earth-mover, however we are able to most likely ascribe that to operator error.)
Subsequent, clomping up a hill fashioned of massive rocks was, if not snug, not significantly harsh because the Rancho shock absorbers smoothed out massive up-and-down motions. Right here I used to be significantly grateful for the AT4’s skid plates and the truth that, not like the truck I drove on the highway, these ones do not have operating boards that would snag on obstacles.
The Sierra’s intelligent MultiPro tailgate is obtainable on the AT4.
The so-called Woods Route is extra like what you would possibly discover out in real-world off-roading, with a slender path that wends between timber and up and down small hills. Slippery leaves and patches of mud from current snow soften posed no actual trouble to the AT4. Nor did clambering up a technical hill strewn with massive rocks towards which I hoped to keep away from smashing the truck’s fog lights. However the sure-footed Sierra frankly turned the entire thing right into a non-vent, so plentiful was its grip and so ample its floor clearance.
An elective coloration HUD show has a particular off-roading mode exhibiting steering, roll and incline angles. The 360-degree digicam system has a dozen or present vantage factors, together with ones pointing straight on the truck’s corners so you’ll be able to see precisely the place you are positioning the tires. That is good to have on a truck that is this lengthy and broad.
Nonetheless civilized for highway use
On the practically 2-hour freeway drive again residence from Eaton’s course, the Sierra AT4 confirmed little proof it had been modified for off-pavement excursions. The knobbly tires did thrum on the highway, even at neighborhood speeds, however the suspension and steering had been simply as stable and stable-feeling as an everyday Sierra. What was noticeable, nevertheless, was that different motorists might inform this truck was particular: Greater than as soon as I noticed different Sierra or Chevy Silverado house owners craning their necks and doing a double-take on the AT4.
The Sierra AT4’s cabin options new seat inserts and an easy-to-use infotainment system.
The one main demerit is EPA rankings of 15 miles per gallon metropolis and 19 mpg freeway, even with the V8 providing cylinder deactivation and stop-start — and with premium gas really useful, no much less. I discovered solely the gentlest cruising proper on the pace restrict would get me near the freeway quantity. Nonetheless, these numbers are par for the course with massive vehicles like this.
Pricing and choices
The 2019 GMC Sierra AT4 begins at $53,200 earlier than vacation spot or choices, and the latter can shortly add up. My truck had an as-tested worth of $65,475. Choices embrace upgrading from the 5.Three- to the 6.2-liter V8 ($2,495), a $995 sunroof and a $1,595 Efficiency Exhaust package. My truck additionally featured the $Three,280 AT4 Premium bundle, which provides an Eight-inch infotainment system with navigation, wi-fi telephone charging, an influence rear window, parking sensors, blind-spot monitoring and facet steps. The $745 Driver Alert Package deal II provides precollision braking with pedestrian detection, lane-keep help and computerized excessive beams. Tack on a pair extra options, just like the surround-vision digicam, and it is simple to see how the truck’s sticker worth can escalate.
The GMC Sierra AT4 will not be a go-anywhere rock-crawler, just like the Chevy Colorado ZR2, or a high-speed desert blaster, just like the Ford F-150 Raptor. Nevertheless, as enjoying round on Eaton’s course proved, it is a lot succesful for the type of mild-to-moderate off-roading that an actual proprietor would possibly need to do on the weekend. Higher nonetheless, the AT4 therapy would not considerably compromise the truck the remainder of the time, making it a stable selection for anybody who desires to take the GMC Sierra past the pavement.
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