At the beginning of the day the vehicles are spotless, their 18-inch wheels, dark-finish exterior trim and purple tow hooks on distinguished show. A few hours later they’re filthy, splattered with filth and dripping muddy water. That is, in any case, precisely how the 2019 GMC Sierra AT4 is supposed for use. It’s a bundle designed for Sierra patrons 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 firm’s 636-acre proving floor has loads of house for romping round within the mud and filth, in addition to numerous paved services for testing all the things from on a regular basis autos to Class 8 vehicles. But as you can inform from our video, the “proving grounds” felt extra like “playground” on my go to. Ready for the filth AT4 is a brand new trim stage for the 2019 GMC Sierra that amps up its off-pavement skills. The truck receives a 2-inch suspension raise complemented by Rancho shock absorbers, the aforementioned Eaton G80 locking diff and both 18- or 20-inch wheels, the previous of which will be outfitted with Goodyear Wrangler Duratrac mud-terrain tires. In different phrases, all of the varieties of upgrades off-roaders would possibly need so as to take their truck out into the woods.
The AT4 comes customary with a 5.3-liter V8, which is rated for 355 horsepower and 385 pound-feet of torque and is mated to an eight-speed computerized transmission. Buyers can improve to a 6.2-liter V8 with 420 hp, 460 lb-ft and a 10-speed computerized. And AT4 patrons 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 5.3 V8 and 15 hp/9 lb-ft for the 6.2 V8. But you will really need that choice for the boisterous, rumbly sound it produces underneath heavy throttle.
Other options embody hill descent management, customary four-wheel drive, dark-finish exterior trim, a body-color grille and bumper, vertical-oriented purple restoration hooks, “Kalahari” seat inserts and rubber ground mats. The AT4 can also be one among solely two trim ranges (the opposite being the glitzy Denali) that will probably be provided with the Sierra’s elective CarbonPro carbon-fiber mattress. GMC has mentioned it is going to roll out the AT4 remedy to different fashions in its lineup, although we’ll have to attend to see what the subsequent mannequin will probably 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.
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No roads, no downside I began out by tackling a handful of obstacles that Eaton makes use of particularly to check car functionality. A giant ditch, for example, is meant to flex a truck’s body and likewise requires beneficiant method and departure angles in order to not scrape physique components. I simply drove the AT4 out and in of the ditch with out situation, the truck’s 2-inch raise serving to and the immense gearing benefit of the four-wheel-drive system’s low vary making ascending the opposite aspect a breeze. Blasting by a deep mud pit was simple 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, should 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 aspect. (Another 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.) Next, clomping up a hill shaped of massive rocks was, if not snug, not notably harsh because the Rancho shock absorbers smoothed out large up-and-down motions. Here I used to be notably grateful for the AT4’s skid plates and the truth that, in contrast to the truck I drove on the street, these ones haven’t got working boards that would snag on obstacles. The Sierra’s intelligent MultiPro tailgate is obtainable on the AT4.
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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 problem to the AT4. Nor did clambering up a technical hill strewn with large rocks in opposition to which I hoped to keep away from smashing the truck’s fog lights. But 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 displaying steering, roll and incline angles. The 360-degree digital camera system has a dozen or present vantage factors, together with ones pointing immediately on the truck’s corners so you’ll be able to see precisely the place you are positioning the tires. That’s good to have on a truck that is this lengthy and large. Still civilized for street use On the almost 2-hour freeway drive again house 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 street, even at neighborhood speeds, however the suspension and steering have been simply as stable and stable-feeling as an everyday Sierra. What was noticeable, nonetheless, was that different motorists may inform this truck was particular: More 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.
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The solely main demerit is EPA scores 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. Still, these numbers are par for the course with large 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 rapidly add up. My truck had an as-tested worth of $65,475. Options embody upgrading from the 5.3- to the 6.2-liter V8 ($2,495), a $995 sunroof and a $1,595 Performance Exhaust package. My truck additionally featured the $3,280 AT4 Premium bundle, which provides an 8-inch infotainment system with navigation, wi-fi telephone charging, an influence rear window, parking sensors, blind-spot monitoring and aspect steps. The $745 Driver Alert Package 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 digital camera, and it is simple to see how the truck’s sticker worth can escalate. The GMC Sierra AT4 shouldn’t 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. However, as taking part in 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 wish to do on the weekend. Better nonetheless, the AT4 remedy does 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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