On the Road Review: GMC Sierra 1500 AT4

If you could drive a full-size pickup truck that delivered 30-plus mpg, could tow up to 9,300 pounds and pump out 460 pound/feet of tire-twisting torque — all while whisking five people down the road in utter comfort — you might be tempted to think, where do I sign up! The reality is that this is possible from GM, Ford and Ram with their latest diesel-powered half-ton pickups. This week’s GMC Sierra is the latest example of what has become the norm.

Introduced last year in the Sierra and its Silverado sibling, the all-new 3.0-liter Duramax turbodiesel is a clean-sheet design based on an aluminum block. A straight six-cylinder layout, while the Ram’s EcoDiesel and the Ford’s Powerstroke are both 3.0-liter V-6 engines, the Duramax employs variable geometry turbocharging and a stratospheric 36,000 PSI common rail injection system to record the highest horsepower in this class, 277 hp, and the second highest torque numbers. For comparison’s sake, the Duramax’s torque output equals the optional 6.2-liter V-8’s 460 pound/feet — and that diesel torque arrives low in the rev range and lasts almost up to the truck’s lofty 5,100 rev-limiter. The Sierra was always quiet, but when pushed, the engine note is remarkably similar to the 6.6-liter Duramax V-8.

Combined with the 10-speed automatic co-designed with Ford, the Sierra’s EPA estimates are 23/30 with 2WD, while our heavily outfitted AT4 Crew Cab is listed at 22/26 mpg with 4WD. In real-world use, fuel economy hovered around 25 mpg with a high of 31 mpg — darned impressive numbers for almost three tons of work/play pick-’em-up truck, as well as fuel economy that exceeds our previous experience with Ford’s new F-150-hybrid.

And unlike the steep financial kick required to jump from gas engines in the heavy-duty pickups to diesel power, the 3.0-liter Duramax requires only $995 more than the 5.3-liter V-8 that is customary in many Sierra pickups. This is making more sense by the minute.

GMC is making the Duramax available in all but base SL model pickups, plus, it is available on the latest Yukon and Denali trimmed SUVs.

Showing off the refined powertrain is the latest AT4 trim level, the counter to Chevy’s Trail Boss series. Using X31 off-road suspension components (skid plates, 2-inch chassis lift with larger Monotube shocks, Goodyear Wrangler DuraTrac tires, limited slip rear diff, electric 4WD shifter, tow package and hill descent control), the AT4 also adds excellent non-skid running boards tucked up against the sill plates, trailer brake controller, plus front and rear tow hooks.

GMC also sent our Summit White AT4 ($54,300 base, rising to $64,430 as shown) equipped with the Multi-Pro tailgate mated to the CarbonPro composite pickup bed ($1,070) that features 12 anchor points, LED lighting, power outlets, rear speaker system, plus a cab-mounted camera and LED light.

While there are inherent advantages to the CarbonPro bed, it is lighter, won’t dent or rust, the MultiPro tailgate is a mixed bag from this viewpoint. The electric release is handy, the various folding components do present load-carrying options, however, the whole package usually requires two hands to manipulate. It is heavy lifting it closed, and if you forget that your receiver hitch is attached you are going to get a nasty dent (or worse with the light and rear camera module at risk) in your fancy tailgate.

Critics will claim that the GMC is not as posh inside as the latest Ram or Ford cabins, or the info/entertainment screen is too small. GMC fans can counter that the intuitive and easily accessed plethora of conventional buttons, knobs and dials in the Sierra is vastly more convenient to use than touchscreens, while the list of standard and available amenities is just as expansive. Android/Apple compatibility is standard, while heated steering wheel, heated rear seating, heated and cooled front seats, plus a rear-view mirror that doubles as a camera are standard here and more available on other Sierra trims.

The Sierra ups the ante with its trailer-towing camera algorithms, excellent 15-inch Heads-Up display (class exclusive), plus all of the driving aids you can realistically use in the technology package.

In the end, GMC is offering a modern turbodiesel powertrain that performs superbly, and achieves a real 30 mpg, all in a nicely styled package that uses a conventional instrument panel in place of overbearing tech. The rear seat is spacious, the daily drivability is top-notch and the Duramax is going to really change driver’s impressions of what a half-ton diesel pickup is capable of.

Tim Plouff

Tim Plouff

Columnist at The Ellsworth American
Tim Plouff has been reviewing automobiles in the pages of The Ellsworth American weekly for nearly two decades.
Tim Plouff

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