2015 GMC Sierra HD

The new-for-2015 GMC Sierra HD and similar Chevrolet Silverado HD models appear to be at the top of their games. But with the rest of the big-league truck group (i.e. Ford’s Super Duty and Chrysler’s Ram 2500/3500) also running flat-out, complacency is not on the options sheet for anyone.

If Detroit’s heavy-duty truck pitches are any indication, buyers in this league are most concerned about hauling, towing and power capacities. The manufacturers’ respective stats in these categories permeate virtually all of their print, broadcast and Web advertising as if achieving numerical superiority represents the sole difference between success and failure.

Well, there’s a lot more too it than that.

Truckers both professional and otherwise are loyal to their chosen brands for a variety of reasons, and motivating them to switch allegiances is at best a difficult proposition. A few extra horsepower here or a 100 more pounds of carrying capacity there won’t easily sway this crowd. Still, the primary players are continually seeking an advantage, which has led to continual strengthening of these beefy brands over the years.

For GM fans, selecting a Sierra HD over a similar Chevrolet Silverado HD mostly boils down to styling preferences since both pickups are virtually identical under the skin. In the Sierra’s case, the grille is more of an in-your-face affair that perhaps conveys a clearer sense of brute strength than the Chevy Silverado’s.

The usual regular cab and crew cab styles return in base, SLT and SLT trim levels. The previous extended-cab version has been replaced by a new double-cab with rear doors that are conventionally hinged at the front but aren’t as wide as the crew cab’s rear doors.

For 2015, both available 66- and 96-inch cargo boxes have been strengthened and the rear bumper has built-in recessed steps at each corner for easier bed access.

Returning again is the loaded-to-the-max GMC Sierra Denali in 2500 and 3500 (three-quarter and one-ton) crew cab models. These premium luxury haulers come with Cadillac levels of premium content that includes leather seating surfaces with heated and cooled front seats, 8-inch touch-screen with built-in navigation system and a premium Bose audio package. Denalis also display chromed honeycomb grilles that differentiate them from rank-and-file Sierras.

Note that the Denali’s base sticker price is $19,500 above the base HD’s $33,600 MSRP.

The carryover powertrains start with a 6.0-liter gasoline V-8 that delivers 360 horsepower and 380 pound-feet of torque. It can be optioned with a compressed-natural-gas fuel system, although you lose 59 horsepower and 47 pound-feet of torque in the process.

For that hard-core grunt work, the optional 6.6-liter turbo-diesel V-8 is rated at 397 horsepower and 765 pound-feet of torque.

Both engines use six-speed automatic transmissions: a GM-developed Hydramatic for the 6.0; and an Allison unit for the turbo-diesel.

GMC mates its “smart exhaust brake system” to the turbo-diesel that, when the vehicle is coasting, holds compressed exhaust gasses inside the engine’s cylinders, creating resistance, which in turn slows down the truck without touching the brakes.

The result is less wear and tear on the brake hardware and greater control for the driver, especially when hauling or towing heavy loads downhill.

Also standard is a Trailer Sway Control program that reduces a trailer’s tendency to wobble about, while hill-start assist prevents the HD from rolling backward when on an incline.

Regardless of engine or load/towing capacity choice, all 2500 and 3500 HDs can be optioned with four-wheel-drive.

As for those all-important stats, the 2015 HD’s maximum hauling capacity has increased to 7,374 pounds from 7,222 and conventional towing capacity has been upped to 19,600 pounds from 18,000. Fifth-wheel-capacity is now rated at 23,200 pounds (formerly 22,500).

As with all GMC pickups, the level of content, body and powertrain customization for the HD line is practically limitless, guided only by your specific needs and budget.