Getting their grand reveal today at the Texas State Fair, the 2015 GMC Sierra 2500 and 3500 Heavy Duty pickups and their upline Denali siblings have been given a wide-ranging revamp that parallels the changes made to their corporate cousins, the 2015 Chevy Silverado 2500/3500 HD. While their all-new-for-2011 platform elements carry forward, the 2015 Sierra HD makeover process has given them a new look, new refinement and additional capability that includes enhanced towing and payload numbers. 

As now, the 2015 Sierra HD set will be available in Work Truck, SLE and SLT models as well as premium Denali trims. Regular cab and crew cab are being joined by a new double cab configuration that replaces the current extended cab, and buyers will be able to choose either an 8-foot or 6.5-foot (crew cab only) bed. The exterior recasting embraces visual cues seen on the all-new 2014 GMC Sierra/Sierra Denali 1500 pickups but creates a look that's even bolder than their lighter-duty counterparts and more aerodynamic than the current Sierra HD family. While SLT and Denali models sport even more distinctive LED lighting elements and trim-specific brightwork/body color accenting, all Sierra HDs feature enhanced engine/underhood cooling capabilities that allow GMC's hardest working pickups to perform at their absolute best regardless of ambient temperatures or load conditions. 

That kind of focused improvement also is evident in the new Sierra HD's cab design, which, like the 1500 series, now consists of nearly 67 percent high-strength steel for added rigidity and uses triple-sealed inlaid doors that help lower drag and interior noise levels. Rear seat access on all stretch variants also has been improved, thanks to front-hinged rear doors on the double-cab and longer rear doors on the crew cab. A similar kind of enlightened upgrading process was applied to the redesigned beds on the Sierra HD. In addition to gaining a convenient CornerStep bumper and built-in hand assists that ease access, the SLE, SLT and Denali all come with integrated bed tie-downs, under-rail LED auxiliary lighting and an EZ Lift-and-Lower tailgate while offering a factory spray-in bedliner.

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Like its exterior remake, the redesigned passenger compartment in the 2015 Sierra 2500/3500 HD family borrows much from the 2014 Sierra 1500. Beyond a more premium look and feel, that stylish and functional transformation brings a tidier dash configuration, better control layouts, a bi-level glovebox, numerous stow spaces, better overall isolation plus new seats that provide more comfort and afford nearly two inches of additional rear legroom on crew cab models. At Denali level, the feature set expands to include additional soft-touch surfaces and real aluminum trim as well as an exclusive 8-inch customizable driver display in place of the baseline gauge cluster, an 8-inch Color Touch navigation radio with Intellilink, Bose premium audio, leather upholstery with heated/cooled front buckets and five standard USB ports.

On a more directly functional front, the 2015 Sierra 2500/3500 HD upgrading program also reaps impressive tangible benefits in the hauling and trailering realms. Although there are virtually no changes to super-stout frame with fully-boxed rails and duty-keyed suspension elements that underpin all Sierra HD configurations, every model - including dually variants -- now has StabiliTrak with Trailer Sway Control and hill start assist. They also feature better integration of the cruise control and Auto Grade Braking (or Diesel Exhaust Brake) that helps maintain more consistent speed and diminishes brake wear while towing in hilly terrain. All but the Work Truck also come with a rear-view camera and front/rear park assist. These new GMC HD pickups also will be available with segment-exclusive safety features including Forward Collision Alert, Lane Departure Warning with GM's Active Safety Seat, and Front and Rear Park Assist. 

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Standard engine in all 2015 Sierra HD models is the familiar 6.0-liter Vortec V8 that makes 360 horsepower and 380 lb-ft of torque. Capable of using regular gasoline or E85, it's backed by a 6-speed automatic transmission in both rear-drive and 4-wheel drive models and can be upfitted with a bi-fuel option that allows it to run on CNG (compressed natural gas). Those needing more capability can step up to the equally well-proven 6.6-liter Cummins Duramax turbodiesel that develops 397 horses but 765 lb-ft of torque. It's paired with an Allison 1000 6-speed automatic that features tap up/down shifting and a Tow/Haul mode. While engine output stats haven't changed, the improved cooling capability of these new Sierra HD models does contribute to significant increases in other key numbers relative to their 2014 counterparts. Maximum payload rises from 7,222 to a best-in-class 7,373 pounds while the Sierra HD's top conventional towing figure now jumps from 18,000 to 19,600 pounds, also a best-in-class figure. Finally, the maximum fifth-wheel tow spec rises from 22,500 to 23,200 pounds. 

The 2015 GMC Sierra 2500 HD and 3500 HD pickups and their Denali offshoots are set to arrive in dealer showrooms during the first quarter of 2014. Pricing and other packaging details will be released closer to their actual on-sale date. 

More Pickup Trucks...

The Ford Atlas Concept hints at what you'll see in the 2015 F-150 redesign

The 2014 Chevy Silverado/GMC Sierra 1500 pickups have earned NHTSA 5-star safety ratings

The Toyota Tundra gets a comprehensive mid-life revamp for 2014


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