• 2015 GMC Sierra All Terrain HD

General Motors has been making trucks since the dawn of the twentieth century and while the trucks have greatly evolved over the last 100 years, they have continued to be strong, purpose-built workhorses. Though the Sierra name has long been associated with GMC’s trucks as a trim level, the name finally became the truck’s model name in 1999 with the introduction of the GMT800 platform. Starting in 2014 (2015 for the HD versions), the GMC Sierra and its corporate twin, the Chevrolet Silverado, have become near luxurious with rich interiors while their capabilities have increased thanks to the new high-tech versions of the familiar 4.3-liter V-6, 5.3-liter V-8, and 6.2-liter V-8. The 2015 GMC Sierra All Terrain HD is ready to do battle with the Ford F-Series Super Duty FX4 and the Ram 2500 Power Wagon with its V-8 Duramax engine, 4G WiFi connectivity and Allison transmission.

GMC announced today the new All Terrain trim package for the HD 2500 and 3500 trucks that will match the capabilities of the Chevrolet Silverado’s Z71 off-road package. Rancho twin-tube shocks, thick coil springs, and wide leaf spring packs help the GMC All Terrain HD to both hit the mud and haul extreme loads either in its bed or hooked to a trailer.

The truck gets the same two engine and transmission options as the rest of GM’s HD lineup: the standard mill is the do-it-all 6.0-liter V-8 or the available 6.6-liter Duramax turbodiesel V-8. The big gas burner mates to the Hydra-Matic 6L90 six-speed auto while the Duramax gets the respected Allison 1000 six-speed automatic.

Besides the additional greasy bits under the skin to help with off-road performance, the All Terrain also comes with a laundry list of upgrades that make it a premium contender. GMC bathed it’s body in chrome bits like running boards and 20-inch alloy wheels while its interior gets a host of techno upgrades like 4G LTE connectivity for Wi-Fi hotspotting, GMC’s IntelliLink infotainment system, and Siri Eyes Free for iPhone users.

Click past the jump for the full rundown on the 2015 GMC Sierra All Terrain HD

  • 2015 GMC Sierra All Terrain HD
  • Year:
  • Make:
  • Model:
  • Engine:
  • Horsepower @ RPM:
    360 @ 5400
  • Torque @ RPM:
    397 @ 3000
  • Displacement:
    6.0 L
  • 0-60 time:
    8 sec.
  • Top Speed:
    110 mph
  • Price:
  • car segment:
  • body style:


2015 GMC Sierra All Terrain HD High Resolution Exterior
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2015 GMC Sierra All Terrain HD High Resolution Exterior
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2015 GMC Sierra All Terrain HD High Resolution Exterior Wallpaper quality
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Falling just below the top-dog Denali trim, the All Terrain still gets many of the Denali’s exterior upgrades. A massive chrome grille with LED and HID jeweled headlights, and a chrome-accented front bumper helps lead the GMC’s way. Chrome-capped towing mirrors, chrome door trim, and chrome running boards help dress up the Sierra’s flanks, while a body-color rear bumper and chrome nameplate emblems keep the rear end looking sharp.

The All Terrain edition gets the same exterior upgrades as the standard HD and half-ton GMC and Chevy trucks. Integrated bumper steps and under-rail bed lighting are among the carry-overs.

Perhaps the most innovative feature of the new All Terrain is the integrated backup lights housed within the side mirrors. The twin LED lights help brighten the area between the front windows and the tailgate for safe nighttime backing. This would come in especially handy when backing a trailer up in tight quarters after dark. Clever.


2015 GMC Sierra All Terrain HD Interior
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Inside, the GMC Sierra All Terrain HD is a familiar environment similar to the all-new 2014 Sierra 1500 truck that debuted last year. The upgraded cabin is much more user friendly and GMC constructed it using much better materials that have better fit and finish than any other GM truck product. While that’s not a hard benchmark to pass, the quality of the new trucks’ interiors is leaps ahead of the outgoing models’.

Since the All Terrain package is its own special deal, the truck’s interior has several badges to remind you what you’re driving. A unique gauge cluster and door seal plates are just two of the stand-alone parts.

Since GMC’s slogan is ‘Professional Grade,’ buyers can fit the truck with loads of tech items that make running a business on the go much simpler. Built-in 4G LTE connectivity with Wi-Fi tethering is available while GMC’s IntelliLink infotainment system offers navigation, voice recognition, and Bluetooth connectivity. What’s more, like the other GM full-size trucks, the Sierra HD comes with five USB ports, a 110-volt standard house receptacle, and at least three 12-volt plugs to keep things charged and running. The center console also gives owners a place for standard size hanging folders.


2015 GMC Sierra All Terrain HD Exterior
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Under the GMC’s hood lies two engine choices: the standard 6.0-liter gasoline V-8 and the available 6.6-liter, Duramax, turbodiesel V-8. Both engines offer good amounts of power for towing and hauling, though the Duramax diesel is the better choice for those towing heavy loads regularly.

The 6.0-liter V-8 cranks out 360 horsepower and 397 pound-feet of torque, and mates to the Hydra-Matic 6L90 six-speed automatic transmission. A 3.73 or 4.10 axle ratio helps put the power to the ground. The 6.6-liter Duramax, on the other hand, pumps out 397 horses and 765 pound-feet of torque. The Allison 1000 six-speed trans sends power to a 3.73 final-drive ratio.

Obviously the Sierra All Terrain HD comes standard with four-wheel-drive. With that comes upgraded suspension bits that help the truck manage rough terrain that would otherwise snag lesser trucks. Aluminum skid plates protect vital parts underneath the truck while twin-tube Rancho shocks help keep the truck riding above any obstacles. 2500 HD models come with their own set of unique, 18-inch, chrome cast-aluminum wheels to help set it apart while the 3500 trucks with dual rear wheels get its own wheel option.

An electronic, two-speed transfer case lies at the heart of the four-wheel-drive system. It offers 2WD, 4WD high, 4WD low, and an Auto mode. The options give the driver the ability to select the perfect setting for the ground ahead. Also standard is the tried-and-true Eaton G80 automatic locking rear differential that seamlessly locks the rear wheels together if it detects a preset amount of slip.

6.0L VVT V-8 – gas/E85 or bi-fuel Duramax 6.6L turbo-diesel
Engine type OHV gasoline or bi-fuel V-8 with variable valve timing OHV turbo-diesel with Piezo-actuated fuel system and variable-vane turbo
Horsepower (hp / kW @ rpm) 360 / 268 @ 5400 (2500HD)
322 / 240 @ 4400 (3500HD)
397 / 296 @ 3000
Torque (lb-ft / Nm @ rpm) 380 / 515 @ 4200 (2500HD & 3500 HD) 765 / 1037 @ 1600
Transmission Hydra-Matic 6L90 6-speed auto. Allison 1000 6-speed auto
Final drive ratio 4.10 or 3.73 3.73


2015 GMC Sierra All Terrain HD Emblems and Logo Exterior
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GMC has yet to release the pricing details on the Sierra HD trucks nor the All Terrain HD model. However, starting with a similarly equipped Chevrolet Silverado 2500 HD, Crew Cab, short box, 4WD in LTZ trim whose price starts at $49,225, we’d venture to guess the GMC 2500 All Terrain HD in the same configuration would start around $52,000. Adding options, of course, always increases the truck’s cost. Count on a $7,000 bill for upgrading to the Duramax.


Ford F-350 FX4

2014 Ford F-Series Super Duty Exterior
- image 524376

Ford’s FX4 package includes many of the same off-road goodies available with the GMC’s All Terrain package, but is available on nearly every trim level of Super Duty. Even a stripped out single cap truck can come equipped with the FX4 Off Road package while costing nearly half as much as the loaded-out Sierra All Terrain HD. Conversely, A F-350 King Ranch can be had with the FX4 package and comes close to matching the GMC’s price point.

A base model F-250 Super Duty starts out just over $30,000 and goes upwards of $70,000 with all the option boxes checked.

Ram 2500 Power Wagon

2014 Ram 2500 Power Wagon High Resolution Exterior
- image 548237

The Power Wagon is in its own league, offering the best off-road performance available in a heavy-duty truck. It comes standard with a 12,000-pound Warn winch integrated into the front bumper, hard-core solid axles front and rear, and an electronically operated front sway bar disconnect for added wheel articulation.

While the Power Wagon is unmatched in its off-road abilities, both the Ford and GMC offer better towing and hauling capacities. It all comes down to what the intended purpose of the truck is and how much money you have to spend.

The base price for the Ram 2500 Power Wagon starts at $45,690.


2015 GMC Sierra All Terrain HD High Resolution Exterior Wallpaper quality
- image 553032

The Sierra All Terrain HD package offers customers a more off-road-biased truck with strong underpinnings for hard-core work. The truck’s major downfall is precisely what makes it so attractive — its almost too nice to use as a work truck. Those looking for a less expensive solution but still need the Sierra’s hauling capacities should look at the Chevy Silverado Z71.

  • Leave it
    • Almost too nice to use hard
    • The 6.0-liter V-8 is getting old
    • Better off-road values found with Ford
Mark McNabb
Mark McNabb was a contributor at TopSpeed from 2013 to 2018. Growing up, Mark always had a mind for tinkering on random items throughout his home and dad’s garage, including a 1953 Ford Mainline and 1971 Corvette Stingray.  Read full bio
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Press Release

GMC today introduced the 2015 Sierra All Terrain HD, a refined, off-road-inspired execution of the brand’s capability that blends exclusive design features with the versatility of 4WD. It goes on sale this summer.

2015 GMC Sierra All Terrain HD High Resolution Exterior Wallpaper quality
- image 553032

“The new 2015 GMC Sierra HD lineup helps customers tackle tough jobs more comfortably, and with the new All Terrain HD, they can do it with greater style,” said Duncan Aldred, vice president of GMC Sales and Marketing. “Equally comfortable whether it’s a night on the town or traversing a remote job site, it has all the capability that customers demand from a GMC heavy-duty truck on the job.”

The new Sierra All Terrain HD is available on 2500HD and 3500HD double cab and crew cab models, and is offered with SLE or SLT trims – all with 4WD, of course, including an electronically controlled transfer case. Also included is the Z71 Off Road package, with Rancho twin-tube shocks, hill descent control and a skid plate.

Sierra HD’s 6.0L gas engine is standard and the Duramax turbo-diesel is available.

The All Terrain’s exclusive design features include a chrome surround on the grille, exterior graphics, aluminum underbody shields and unique 18-inch six-spoke chrome cast-aluminum wheels. Twenty-inch chrome aluminum wheels are available on 2500HD, while 3500HD models also include adjustable outside camper mirrors with a chrome cap.

2015 GMC Sierra All Terrain HD High Resolution Exterior
- image 553033

Additional exterior content includes light-emitting diode signature headlamps, body-color bumpers (chrome bumpers available), chrome mirrors covers and body side moldings and chrome front-lower bumper plate. Inside, a carbon fiber-inspired theme distinguishes the All Terrain from other models and includes the ALL TERRAIN logo on the instrument cluster. A rearview camera system also is standard.

The new All Terrain HD also includes the latest connectivity technology, including IntelliLink and new OnStar with 4G LTE and standard built-in Wi-Fi hotspot. Enhanced features for IntelliLink include Text Messaging Alerts for smartphone users with Bluetooth profile (M.A.P.), which reads incoming texts through the vehicle’s speakers, and Siri Eyes Free for iPhone iOS 6 and iOS 7 users to enhance connectivity and convenience.

New OnStar with 4G LTE connection provides a mobile hub for drivers and passengers to stay connected. The hotspot is on whenever the vehicle is on and comes with a three-month/three-gigabyte data trial.

Additional new and enhanced features introduced on the 2015 Sierra HD lineup include:

CornerStep rear bumper, EZ Lift and Lower tailgate, standard locking tailgate, standard upper tie-downs and other features that make cargo handling easier
Standard StabiliTrak with Trailer Sway Control on all models
Integrated cruise control, auto grade braking and diesel exhaust braking, for greater driving control and reduced brake wear on grades
Enhanced cooling airflow, which enables the Duramax turbo diesel and 6.0L gas engine to better maintain full power, even under heavy loads and high ambient temperatures
New Duralife™ disc brake rotors that offer up to double the service life (late availability).

2015 GMC Sierra All Terrain HD High Resolution Exterior
- image 553034

New, heated, power-adjustable trailering mirrors are offered on SLE and SLT – including All Terrain – and Denali (late availability), including segment-first back-up lamps. The large mirrors feature 51 square inches of flat mirror surface positioned over a 24.5-square-inch non-heated or power-adjustable convex mirror surface. A new auxiliary back-up lamp is integrated in each mirror to enhance trailer visibility when backing up, as well as an amber auxiliary clearance lamp. The SLE trailering mirror is black and can be extended and folded manually. The SLT/Denali mirror has a chrome cap and adds a power-folding feature.

The 2015 Sierra HD also offers segment-exclusive safety features such as forward collision alert, lane departure warning with an active safety seat, and front and rear park assist. Head-curtain and seat-mounted side airbags are standard on 2500HD and available on 3500HD models.

2015 GMC Sierra All Terrain HD High Resolution Exterior
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All models are backed by GMC Pro Grade Protection, with two years of scheduled maintenance – including diesel exhaust fluid – a three-year/36,000-miles bumper-to-bumper warranty and a five-year/100,000-mile powertrain warranty.

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