2015 Chevy Silverado, GMC Sierra heavy duty trucks unveiled

Thu, 26 Sep 2013

Proving just how important trucks are in the Lone Star State, General Motors has chosen the State Fair of Texas to reveal its new heavy-duty trucks from Chevrolet and GMC. Looking to take some of the wind out of the sails of the 2014 Ram HD and 2015 Ford F-Series Super Duty, the 2015 Chevy Silverado HD and 2015 GMC Sierra HD will have plenty to brag about when they go on sale in the first quarter of next year.

The bragging starts right up front with two available engines. The standard engine is a Vortec 6.0-liter V8 that produces 360 horsepower in the 2500HD and 322 hp in the 3500HD to go along with 380 pound-feet of torque in all applications. The true benefit of this powerplant is that buyers can opt for it to run on straight gasoline, E85 FlexFuel or even compressed natural gas (CNG). For maximum towing and even more flexibility, the 6.6-liter Duramax turbodiesel B20-capable V8 is the way to go, with its carryover 397 hp and 765 lb-ft of torque. Though the max towing abilities of 23,200 pounds (with a fifth-wheel trailer) are less than the 30,000-pound rating of the new Ram, the GM HD trucks offer better conventional trailer towing (19,600 pounds) and payload (7,374 pounds) than rival heavy-duty trucks...for now. The Duramax is paired with a six-speed Allison automatic transmission, while the gas engine gets GM's six-speed Hydra-Matic – no manual transmissions are offered.

Including the engines, GM continues to offer a broad range of configurations (more than 150, to be exact) including three cabs, two cargo bed lengths, numerous trim levels and, of course, the choice of single- or dual-rear wheels on the 3500. The HD trucks have faces that are similar to their half-ton counterparts, with the exception of a larger grille and bigger for improved air flow, and like the current HD offerings, the new Silverado HD and Sierra HD DRW models feature a one-piece bed design incorporating the fender extensions.

Some unique-to-GM conveniences available on these HD trucks include the rear corner step bumper, optional in-bed LED lighting and the EZ Lift-and-Lower tailgate, features first made available on 1500 models. The Sierra HD will be offered in the top Denali trim level, but it doesn't look like Chevy buyers will be able to get an HD version of the newly introduced Silverado High Country.

For more information, check out the press releases from Chevy and GMC posted below.

Silverado HD: Engineered to Make the Tough Jobs Easier

• Built strong, with best-in-class payload and conventional towing
• Built smart, with advanced chassis controls for more confident towing
• New cabs and interiors for all-day comfort, on the job and on the road
• Diesel, gas and CNG power available on 2500 and 3500 models

DETROIT – The new 2015 Chevrolet Silverado HDs are engineered to be stronger, smarter, and more confident than ever.

"Heavy-duty pickups are tools that people use to tow heavy trailers and haul big loads," said Jeff Luke, executive chief engineer. "A great tool like the new Silverado HD pickup doesn't just get the job done, it makes the work easier, and helps you feel more confident tackling the really tough jobs."

Updates for the 2015 model year include:
• All-new exterior styling with enhanced cooling air flow, which enables Silverado's 6.6-liter Duramax turbo diesel and 6.0-liter Vortec V-8 to better maintain full power, even under heavy loads and high ambient temperatures
• Integrated cruise control, Auto Grade Braking and Diesel Exhaust Braking (on diesel models) that help make tough towing easier
• A 6.0L bi-fuel V-8, which can run on either gasoline or compressed natural gas, will be available on regular-cab, crew-cab and new double-cab Silverado 2500 and 3500 models.
• Standard StabiliTrak with Trailer Sway Control on all models including 3500 duallys.
• All new cabs and interiors that provide increased space and comfort, with extensive storage space tailored to the way customers use full-size trucks.
• Chevrolet MyLink, which provides powerful connectivity for work or family with simple, intuitive controls.
• New 6.5- and 8-foot boxes with standard CornerStep bumpers, EZ Lift and Lower tailgates, and other features that make cargo handling easier.

New exterior design for enhanced cooling, reduced wind noise

Silverado HD's all-new exterior communicates strength and capability, while also enhancing aerodynamics for improved efficiency and reduced wind noise, It also improves cooling for more consistent power under tough conditions.

"The passion we have for trucks is reflected in every line and powerfully sculpted machined surface of the HD Chevrolet," said Tom Peters, design director. "From the dramatic sculpture of the one-piece structural bumper, to its muscular hood and side profile, the design reflects a function-driven solution."

The design of the 2015 Silverado HD is as much about brains as brawn. New inlaid doors, which fit into recesses in the body side, help reduce wind noise for a quieter cab. The smallest details of the body, such as the roof and tailgate spoiler, were tuned in a wind tunnel to smooth airflow over the truck for reduced noise and improved aerodynamic efficiency.

Because HD pickups are frequently used for towing under adverse conditions, engineers paid particular attention to airflow for both engine cooling and the engine air intakes. Starting with air inlets sized to reduce drag and improve efficiency, engineers tested cooling airflow in the wind tunnel and on the road to make sure the engines could maintain power on long upgrades at high ambient temperatures. Careful sealing of the front end also ensures that air entering the engine intake remains cool, for optimum performance under tough conditions.

"It is one thing to generate big power numbers in cool weather, and quite another to maintain power and torque when towing up a long grade on a blistering summer day," said Luke. "We think customers will appreciate all of the work that went into the cooling for the new Silverado HD when they get a chance to really put it to the test."

Integrated controls for easier towing

The new Silverado HDs are also designed to bring new levels of confidence to tough towing through further refinement of Silverado's available Cruise Control, Auto Grade Braking, and Diesel Exhaust Brake. The integration of these features helps the 2015 Silverado HD maintain a set speed up and down grades, even when towing a heavy trailer in mountainous terrain.

"The customer sets the desired speed, and the truck will do the rest – increasing or decreasing power, downshifting to increase engine braking, and engaging the exhaust brake on the diesel engine," said Luke. "You feel much more confident and in control, because you aren't constantly working to stay a step ahead of the truck and trailer."

To activate the Auto Grade Braking on either gasoline or diesel Silverado HDs, the driver presses and holds the Tow/Haul button in the shifter for three seconds. The transmission will then automatically downshift when needed to enable engine braking to help slow the vehicle.

In addition, on Duramax diesel models, the driver can also engage the Diesel Exhaust Brake, which uses the variable vanes in the turbocharger to smoothly and quietly create additional backpressure in the engine to help slow the vehicle. The combination of the exhaust brake and the automatic transmission downshifts helps the driver maintain the desired speed, even on long, steep highway downgrades.

StabiliTrak with Trailer Sway Control is now standard on all Silverado HDs, including 3500 dually models, providing additional security to the drive.

Built strong, with rugged truck hardware

The foundation of 2015 Silverado HDs is a family of fully boxed frames, which use large cross sections, hydroforming and high-strength steels in key areas. The stiffness of the frames contributes to improved handling and ride comfort, while the strength of the frames enhances payload and towing capability.

The Silverado HDs independent front suspension is specifically engineered for HD pickup use, with forged steel upper control arms and precision machined cast iron lower control arms. Torsion bars are tailored to the weight ratings of the trucks, ad allow easier trim height adjustment to account for the weight of snow plows or other accessories.

Rear springs are asymmetrical leaf springs, which balance ride and load carrying, and improve control of axle hop. The steel springs, three inches wide, have been proven to perform year after year under the toughest conditions.

Payload and towing capabilities of the 2015 Silverado HD are increased from 2014 models:
• Maximum available payload is 7,374 pounds, the best for any HD pickup, up from 7,222 pounds.
• Maximum available conventional towing is 19,600 pounds with the available factory hitch, up from 18,000 pounds and also best in class.
• Maximum available fifth-wheel towing is 23,200 pounds, up from 22,500 pounds.

Silverado HD is available in more than 150 combinations of cabs, bed lengths, powertrains, drivetrains and axle ratios, enabling customers to spec exactly the right truck for their towing and hauling needs.

The team that created the 2015 Silverado HD went to extremes to deliver a truck that would live up to Chevrolet's reputation for building the most dependable, longest lasting pickups, said Luke.

For example, GM's new full-size truck family will undergo more than 6 million miles of durability testing in the torture chambers at the Milford Proving Ground, over the deserts and mountains of Nevada and across the frozen flats of Kapuskasing, Ontario. That's equivalent to 240 trips around the earth. In addition, the trucks will accumulate more than 7 million real-world miles during final testing, bringing total test miles to more than 13 million.

New cabs and interiors for all-day comfort

The 2015 Silverado HD receives the same updates to the interior, cab structure, and door designs as the new Silverado 1500, which has received positive reviews for its quieter cab and roomier, more comfortable interior.

"Whether they use their truck as their office or travel cross country with a big trailer in tow, owners of HD pickups often spend long days behind the wheel," said Luke. "The quiet, comfortable, connected interior of the 2015 Silverado HD reflects an intense focus on the way truckers live and work."

The upright instrument panel, six-gauge instrument cluster and multiple storage options are tailored specifically to the needs of truck customers. Controls are functional, logically placed and easy to operate with work gloves on. For example, the available Integrated Trailer Brake Controller is mounted high on the left side of the instrument panel, where it can be easily adjusted, and it displays Gain on the Driver Information Center in the instrument cluster. The new Chevrolet MyLink, standard on all models except the base work truck, provides easy-to-use connectivity for the job site or the family vacation, with natural voice recognition and enough ports and power outlets to support multiple devices.

The new truck cab is stronger, with nearly two-thirds of the structure made from high-strength steel for a confident feel and improved safety. The cabs feature inlaid doors, which fit snugly
into recesses in the body sides for reduced turbulence and wind rush. Combined with new triple door seals, the doors help create a quieter interior.

The rear doors on crew-cab models are larger, and combined with revised seats, create approximately two inches more rear legroom, and enable easier entry and exit for back seat passengers.

A new double-cab model, which features forward-hinged rear doors, replaces the previous extended cab, and allows easier access to the back seat, especially in tight parking spaces.

Rugged powertrains for gas, diesel, E85 and CNG

The 2015 Silverado HD offers three powertrains specifically tailored for tough tasks and dependable service.

The proven Duramax 6.6L turbodiesel and Allison 1000 six-speed automatic transmission combination will continue to be available on both 2500 and 3500 Silverados.

Rated at 397 horsepower and 765 lb-ft of torque, the Duramax diesel features piezo-actuated fuel injectors for improved performance and efficiency, and a variable vane turbocharger that also acts as an exhaust brake to help control vehicle speed when needed on long downgrades.

The Allison 1000 transmission features a driver shift control with tap up/tap down shifting and a Tow/Haul mode that reduces shift cycling for better control and improved cooling when towing or hauling heavy loads.

The standard engine on all Silverado HDs is a 6.0L Vortec gas V-8 with continuously variable valve timing, matched with a six-speed automatic transmission. It is rated at 360 horsepower and 380 lb-ft of torque on 2500 models, and is specifically engineered for low-end torque. A version rated at 322 horsepower is standard on 3500s. Pickups with either version are E85 FlexFuel capable.

A bi-fuel version of the 6.0L V-8, with special hardened valves and valve seats to enable operation on gasoline or compressed natural gas, will be available in all three models of the new Silverado HD – regular-cab, crew-cab and double-cab.

Chevrolet will continue to work with a second-stage manufacturer to offer a single-source option for its CNG vehicles. The bi-fuel trucks are built with the specially designed engine, the fuel system is installed by GM's Tier One supplier, and the completed vehicle is delivered directly to the customer. This process makes ordering the bi-fuel option as seamless as ordering a truck powered by gas or diesel, and ensures the highest level of durability, reliability and safety.

Smart solutions for cargo management

The pickup box is made from roll-formed steel for increased strength and reduced mass, compared with the stamped beds used by major competitors, and it features a range of smart solutions for everyday life.
Silverado's CornerStep bumper, combined with hand assists built into the new standard box rail protectors, makes it easier to access cargo in the box, especially useful on HD pickups, with their higher ride height. The box is also available with new upper tie-down hooks, under-rail light-emitting diode lighting, and an EZ Lift and Lower tailgate.

An available spray-in bed liner, which bonds to the steel bed to create permanent, water-tight protection for the box, covers the entire bed interior surface below the side rails, including the tailgate and front box top rail.

Enhanced safety and security

The 2015 Silverado HD will be available with 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 2500 and available on 3500 models.

Like all Silverados, the 2015 Silverado HD is backed by the best pickup coverage in America, including:
• 3 year/36,000 mile limited new vehicle warranty;
• 5 year/100,000 mile limited powertrain warranty;
• 2 year/24,000 mile schedule maintenance coverage, including diesel exhaust fluid.

Accessories for a wide range of tasks

The 2015 Silverado HD will be available with a broad range of dealer-installed accessories. Exterior accessories include four-inch or six-inch assist steps in chrome or black, 20-inch wheels, body-side moldings, and a range of chrome accents.

All-weather or carpet floor mats help keep the elements at bay, and storage accessories for the console and under the seat help organize tools and information.

Available for the box are retractable side steps, drop-in or spray-in bed liners, bed mats and rugs, and tonneau covers, as well as Trac Rac ladder racks and UWS tool boxes.

Manufacturing

2015 Silverado HD pickups will be assembled in Ft. Wayne, Ind. and Flint, Mich.
Founded in 1911 in Detroit, Chevrolet is now one of the world's largest car brands, doing business in more than 140 countries and selling more than 4.5 million cars and trucks a year. Chevrolet provides customers with fuel-efficient vehicles that feature spirited performance, expressive design, and high quality. More information on Chevrolet models can be found at www.chevrolet.com.

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New 2015 GMC Sierra HD: Smart, Capable and Comfortable
Bold style, enhanced interior and helpful technologies support class-leading capabilities

DALLAS – Designed to deliver class-leading capability with enhanced comfort and smarter technologies, the new 2015 GMC Sierra HD lineup advances a 111-year legacy of professional heavy-duty trucks.

The new Sierra HDs arrive in the first quarter of 2014, including 2500HD and 3500HD models, and the Sierra Denali HD, which matches do-it-all capability with an exclusive package of design and upscale interior amenities.

Segment-leading capabilities across the range include the highest payload – 7,374 pounds – and the highest conventional trailering rating – 19,600 pounds. The maximum fifth-wheel trailering rating is 23,200 pounds. Gas and Duramax diesel powertrains are offered, including a bi-fuel option that pairs the gas engine with a compressed natural gas system.

"Sierra HD trucks are engineered without compromise to deliver not only the capability today's heavy-duty truck customers demand, but the quality and refinement that inspire confidence with every task," said Tony DiSalle, vice president of GMC Marketing. "We've been doing this for more than a century, and nobody knows trucks like GMC."

Bold styling and an all-new, more comfortable and technology-infused interior are carried forward from the 2014 Sierra 1500, including new double cab and revised crew cab body styles. Larger rear doors on each, along with new seat designs, enable easier entry and exit from the rear seat and two inches of additional legroom on crew cabs.

The new interior is also designed to help drivers and passengers whether they're on the job or on a weekend getaway, with easier-to-reach, more intuitively located controls, more storage compartments, more plug-ins for electronic devices and the latest-generation GMC IntelliLink infotainment system – with an eight-inch-diagonal color touch screen.

"Forget the notion that heavy-duty trucks are basic tools with a trailer hitch," said DiSalle. "The 2015 Sierra HD trucks can haul the heaviest load with unmatched comfort and technology that make the job easier."

Additional new and enhanced features for the 2015 Sierra HD lineup:
• CornerStep rear bumper, EZ Lift and Lower tailgate, standard upper tie-downs and other features that make cargo handling easier
• Standard StabiliTrak with Trailer Sway Control on all models, including 3500HD dually
• Integrated cruise control, auto grade braking and diesel exhaust braking (diesel models), 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
• Latest-generation IntelliLink infotainment system, which offers a variety of connectivity options for devices of all types and available navigation

Sierra Denali HD details

The distinctive Sierra Denali HD features a signature Denali chrome grille, unique interior decorative trim, a polished stainless steel exhaust outlet (gas models) and body-color front and rear bumpers. Complementing the soft-touch instrument panel trim and aluminum trim are Denali-specific interior details, including script on the bright door sills and embossed into the front seats.

Sierra Denali's high-tech interior also features an exclusive eight-inch customizable driver display that can show relevant settings, audio and navigation information in the instrument panel. Sierra Denali's standard eight-inch Color Touch navigation radio with Intellilink, located above the center console, serves as the main hub for Bluetooth-connected phones and portable devices connected through five standard USB ports.

Other features standard on Sierra Denali include projector-style headlamps with light-emitting diode signature daytime running lights, a Bose audio system, heated and cooled leather front bucket seats, a heated steering wheel and a power sliding rear window with defogger.

Sierra HD design and exterior features

Sierra HD trucks have a new face that conveys GMC's professional grade aesthetic with greater technical precision, including an all-new headlamp and grille design, power-dome hood – with specific badging on Duramax-equipped models – and a one-piece chrome bumper (body-color bumper on Denali). SLT and Denali models feature GMC's signature C-shaped LED daytime running lamps within the headlamp housings.

The new exterior design backs up its bold, advanced styling with efficiency-enhancing functionality. Improved aerodynamics allow the trucks to slip through the air with less drag and reduced wind noise, while the new grille design supports enhanced engine-cooling performance. It enhances efficiency and ensures Sierra HD delivers optimal performance under the toughest conditions, such as towing on a mountain grade.

New inlaid doors, which fit into recesses in the bodyside, help reduce wind noise for a quieter cab, while details including like the roof and tailgate spoiler were tuned in the wind tunnel to smooth airflow over the truck for reduced noise and improved aerodynamic efficiency.

Like the 2014 Sierra 1500, a new double cab body replaces the previous extended cab. It features longer, front-hinged rear doors with outside pull handles at the rear, providing improved access in tight parking spaces. New structural B-pillars were added to add to a solid feel.

Unlike trucks with rear-hinged doors, Sierra's double cab design allows rear passengers to enter and exit the vehicle with the front doors remaining closed. Crew cabs feature resized doors, too, including longer rear doors, which also make it easier to climb in and out of the rear seat.

Approximately 67 percent of each cab is constructed with high-strength and ultra-high-strength steels, used in the A-pillars, B-pillars, rockers and roof rails, as well strategic sections on the interior structure. Ultra-high-strength steel is used in areas of the rocker panels and underbody to help improve performance in crashes.

Cargo box innovations

Sierra HD models are available with 6'6" and 8' box lengths that are stronger and more durable, easier to use and offer greater cargo flexibility. The new CornerStep rear bumper – introduced on Sierra 1500 – is standard. It features integrated steps at each corner designed to accommodate large boots, with textured pads for sure-footed grip.

Sierra HD's boxes also feature four integrated cargo tie-down provisions built into the lower corners and new, standard upper tie-downs. The patented upper hooks – each rated at 250 pounds – can be placed in several locations around the upper bed rails, providing flexibility for securing loads of all shapes and sizes.

The EZ Lift-and-Lower tailgate is standard on SLE, SLT and Denali models. An internal torsion bar in the tailgate reduces the effort to raise and lower it, while a rotary damper allows for a controlled and more gradual lowering motion when opening. The tailgate is also easily removable without tools.

LED cargo box lighting is standard on SLE, SLT and Denali models. Two LED lights are mounted under the box side rails and are activated by a switch on the instrument panel, providing a light source when a tonneau cover is installed or a flashlight isn't available.

The boxes come with a two-tier loading design and offers more than four feet of loading space between the wheel houses, allowing standard 4' x 8' sheets of plywood to stack flatly on the box floor. There is also more than five feet of load space between the box walls. An available, factory-installed spray-in bed liner provides protection for the box floor and walls.

The two-tier design allows customers to insert a platform to separate items during hauling or conceal valuables below, such as power tools. It incorporates resting points at the same level as the tops of the wheel houses – enabling the platform to effectively divide the box into upper and lower sections. There are also built-in provisions for cargo bulkheads to subdivide the box even further.

A wide range of utility-enhancing accessories offered through GMC dealers makes Sierra HD cargo boxes more functional. They include tool boxes, bed liners, bed mats, box nets, ladder racks and more.

Intuitive, integrated interior

The 2015 Sierra HD lineup benefits from interior introduced on the 2014 Sierra 1500. Premium materials, greater attention to detail and purposeful technologies define the passenger space, with soft-touch materials and available aluminum trim providing premium accents to an interior designed to be a productive, easy-to-use environment.

An upright instrument panel is designed for visibility and accessibility, while the knobs and buttons are large. All knobs are coated using a rubber-over-mold technology that makes them easy to grip, even with gloves.

A new instrument cluster on all models features six gauges with an available centrally located, 4.2-inch-diagonal color driver information center, with vehicle status details, a trip computer and radio and navigation readouts.

A second, high-mounted glove box with a flat floor joins the traditional box below. Each of Sierra HD's doors has storage crafted to hold most beverage containers and other personal items. Along the center stack and center console are additional cupholders, discreet compartments large enough for most laptop computers, and connectivity options. Sierra HD is available with a 110-volt outlet, up to five USB ports, four 12-volt outlets and an SD card slot.

Available IntelliLink connectivity uses a reconfigurable eight-inch color touch screen with an intuitive layout and easy-to-read icons that control audio features, a Pandora app, Bluetooth phone features and available navigation with all-new map displays. Many of the system's features can be controlled by natural-language voice command, allowing drivers to keep their eyes on the road and hands on the wheel.

Sierra HD's seats use dual-density foam designed to stay comfortable over long hours and continue to look great after years of use. Leather-appointed and cloth seating are offered, and Sierra's new high-wear cloth is designed to last longer and resist staining.

Heavy-duty foundation for greater capabilities

All Sierra HD models feature fully boxed frame assemblies – 18 different assemblies that accommodate more than 150 possible vehicle configurations across the lineup. Strategic enhancements support greater capabilities, including:
• Segment-leading maximum payload of 7,374 pounds
• Segment-leading conventional towing rating of up to 19,600 pounds (with factory-installed, frame-mounted box-tube hitch)
• Maximum fifth-wheel towing rating of 23,200 pounds.

A short-long arm/torsion bar front suspension is used on all models and features forged steel upper control arms and precision-machined cast iron lower control arms. Five different torsion bar rates support five different front gross axle weight ratings to help stabilize the range of trim heights of various models under load – including snow plows – while enhancing appearance, handling, durability, tire wear and alignment.

At the rear, an asymmetrical leaf-spring design minimizes axle hop and enhances traction control efficiency. A two-stage leaf-spring design is used on 2500HD models and three-stage design is employed on 3500HD model. All models feature 3-inch-wide (76 mm) leaf springs.

The Z71 Off Road suspension is available on SLE and SLT models and includes 35mm deflective disk twin-tube shock absorbers, off-road jounce bumpers, 33mm front stabilizer bar and a skid plate package.

Vehicle control technologies

Sierra HD's advanced vehicle control technologies are designed to make tough jobs easier and more comfortable, while also contributing to a safe driving experience, particularly when hauling cargo or towing a trailer.

StabiliTrak electronic stability control is standard on all single-rear-wheel models and – new for 2015 – 3500HD dual-rear-wheel models. It incorporates trailer sway control and hill start assist. Trailer sway control provides an added measure of confidence when towing a trailer by automatically intervening with braking and/or reduced engine power to bring the trailer under control and keep it on its intended path.

Hill start brake assist senses potential "rollback" when braking on an incline and holds full brake pressure momentarily after the driver lifts his or her foot from the pedal, preventing rollback – it is particularly effective when towing, giving the driver time to switch from the brake pedal to the gas pedal.

Available cruise control, auto grade braking, and diesel exhaust brake features help the vehicle maintain a set speed up and down grades, even when towing a heavy trailer. With the diesel exhaust brake feature, the turbocharger is used to smoothly and quietly create additional backpressure in the engine to help slow the vehicle. The combination of the exhaust brake and the automatic transmission downshifts helps the driver maintain the desired speed, even on steep grades.

Additional driver control features include four-wheel disc brakes, which are standard on all models, and four-wheel, four-channel ABS, which is standard on all single- and dual-rear-wheel models.

A rear-vision camera system is standard on SLE, SLT and Denali to give the driver a view of items behind the vehicle. It can also assist with lining up in front of a trailer.

Proven powertrains

A Vortec 6.0L gas V-8 with variable valve timing is matched with the Hydra-Matic 6L90 six-speed automatic transmission as the standard powertrain across the Sierra HD model range. This combination is engineered to deliver excellent performance and efficiency, especially at low-rpms. It is rated at 360 horsepower (268 kW) and 380 lb-ft of torque (515 Nm) in 2500HD models and 322 horsepower (240 kW) and 380 lb-ft (515 Nm) in 3500HD.

The 6.0L engine is also available in a bi-fuel model that features special hardened valves and valve seats that enables it to run on compressed natural gas or gasoline. The CNG fuel system is installed by a GM supplier and completed vehicles are delivered directly to the customer, making the purchase process as seamless as ordering any other option.

The Duramax 6.6L diesel and Allison 1000 six-speed automatic transmission powertrain combination is available on all 2500HD and 3500HD models, with highlights that include:
• 397 horsepower (296 kW) at 3,000 rpm
• 765 lb-ft of torque (1,037 Nm) at 1,600 rpm
• High-pressure (30,000 psi/2,000 bar) Piezo-actuated fuel system for greater fuel efficiency, improved performance and reduced emissions
• Variable vane turbocharger that also acts as an exhaust brake to help control or slow the vehicle's speed
• Selective catalytic reduction after-treatment system using diesel exhaust fluid injection to provide the best overall diesel characteristics and performance – with a range of about 5,000 miles (8,000 km) between DEF refills
• Combustion and after-treatment optimized to provide about 700 miles (1,125 km) between diesel particulate filter regenerations
• B20 biodiesel capability for an alternative fueling option.

The Allison 1000 features driver shift control with tap up/tap down shifting and a patented elevated idle mode cab warm-up feature. Also, the tow/haul mode reduces shift cycling for better control and improved cooling when towing or hauling heavy loads.

By Jeffrey N. Ross