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GMC is expanding its exclusive Denali sub-brand with the debut of the 2013 Terrain Denali, bringing a new level of style and power to the luxury small SUV.

“Denali is growing fast,” said Tony DiSalle, U.S. vice president of GMC Marketing. “With seven different models, sales for this brand within a brand increased 79 percent from 2010 to 2011. With this in mind, the decision to create a more-upscale Terrain was an easy one.”

More power, same efficiency

With the introduction of the Terrain Denali, GMC also announced a new 3.6-liter V-6 engine with direct injection and continuously variable valve timing will replace the current 3.0-liter V-6 engine in Terrain lineup for the 2013 model year. SAE certified at 301 horsepower (224 kW) and 272 lb.-ft. (369 Nm) of torque, this engine makes more power and torque, but is expected to deliver fuel economy equal to its predecessor.

The new V-6 uses lightweight components that contribute to the Terrain’s fuel efficiency while boosting its horsepower. An integrated cylinder head/exhaust manifold design saves about 13 pounds compared to a non-integrated design.

while a composite intake manifold saves about 5.5 pounds vs. an aluminum intake. Additionally, a lightweight structural front cover and high-strength connecting rods save additional weight.

Terrain’s standard Ecotec 2.4-liter I-4 with direct injection and continuously variable valve timing is also available for buyers looking to combine Denali’s high-end appointments with a best-in-class 32 highway mpg (2WD model). Front-wheel drive is standard on Terrain Denali, with all-wheel drive available for both engines.

New dual-flow dampers are exclusive to the Terrain Denali’s suspension system. This technology provides a smoother ride and improved handling by controlling suspension dampening across a broader range of driving conditions.

Signature design cues

Inside and out, the 2013 Terrain Denali features high-end details. Models with the 2.4L engine feature 18-inch wheels, while the V-6 engine is paired with 19-inch wheels. Other Denali-specific exterior features include:

Signature chrome grille
Satin chrome accents
Body color front and rear fascias
Body color rocker panels with satin chrome molding
New headlamp and taillamp designs
Dual chrome finish exhaust outlets (single outlet on 2.4L)
Terrain Denali’s cabin updates are highlighted by soft-touch Jet Black leather, which lines the seats and door inserts. Contrast stitching and red accent lighting contribute to an inviting interior. Other Denali-exclusive interior details include:

Soft-touch instrument panel with French stitching
Leather-wrapped steering wheel with smoked mahogany wood accents
Embossed Denali logos on front seatbacks
Smoked mahogany wood trim accents
Denali illuminated front sill plates
Eight-way power driver and passenger seat
Class-leading technology

Terrain Denali comes standard with many of GMC’s leading technologies, including a color touch radio with IntelliLink. This new infotainment system features a reconfigurable home screen; intuitive voice commands; Bluetooth smartphone integration; control of streaming internet radio apps such as Pandora and Stitcher; and iPod controls with Gracenote music database technology.

Forward collision alert and lane departure warning are standard on Terrain Denali. They use the industry’s first single-camera crash-avoidance system to visually and audibly warn drivers when a collision is imminent or the vehicle crosses a lane marker.

In addition, side blind zone and rear cross traffic alert help avoid collisions by using radar to watch spots the driver may not be able to see – and provide visible and audible warnings.

Convenience features, such as a programmable power liftgate, are standard on Terrain Denali. At the touch of a button, owners can access the vehicle’s 63.9 cubic feet of cargo space (behind the first row), while a memory function stops the liftgate at a chosen height to help shorter drivers or accommodate low garage heights.

Available technologies include color touch navigation and a rear-seat entertainment system.

As with every new GMC, the Terrain Denali comes with six free months of OnStar’s Directions and Connections plan. It includes Automatic Crash Response, Turn-by-Turn Navigation, roadside assistance, emergency services link, stolen vehicle assistance and remote door unlock.

Pricing and availability of the 2013 Terrain Denali and Terrain 3.6L V-6 models will be announced closer to the on-sale date in the third quarter of 2012.

2011 GMC Sierra HD Concept

GMC just released the official detail and image for 2011 GMC Sierra HD Concept.

The GMC Sierra All Terrain HD concept is an exploration of heavy-duty truck capability combined with greater off-road versatility. It is highlighted by a bold exterior design, enhanced all-terrain suspension and premium details expected of a GMC – all designed to enable greater access to off-road destinations.

The new 2011 Sierra HD underpins the All Terrain HD concept, with a modified, production-based 4WD chassis and the Duramax diesel/Allison 1000 six-speed powertrain. The enhanced suspension and unique body dimensions, including increased ground clearance and wider track, as well as greater approach/departure angles, deliver off-road capability while maintaining HD levels of payload and trailering capacity.

“The Sierra All Terrain HD concept takes GMC’s outstanding new HD platform to the next level, marries it to the legendary Duramax diesel/Allison transmission, and provides a heavy-duty expression of GMC’s premium All Terrain package,” said Lisa Hutchinson, GMC product marketing director. “It delivers the exceptional capabilities of the Sierra HD – hauling, towing and performance – and applies them to the toughest driving environments. It’s the ultimate professional-grade toolfor construction crews, ranchers and adventurers whose activities aren’t limited by where the pavement ends.”

The Sierra All Terrain HD features a unique five-foot, eight-inch Crew Cab/short box body configuration that supports a wheels-at-the-corners proportion. Shorter in overall length than production Sierra HD models, the concept’s dimensions contribute to greater approach/departure angles. Additional off-road elements include:

Wider, 73-inch (1,853 mm) track for greater stability
Approximately 3 inches (76 mm) greater ground clearance
Custom front upper and lower control arms
Specially constructed Fox off-road shocks with remote fluid reservoirs (integrated in the wheel house liners)
Front and rear jounce shocks
Electronic front stabilizer bar disconnection
35-inch-tall BFGoodrich KM2 “mud terrain” tires mounted on 20-inch machined aluminum wheels
Full composite underbody protection.
“The capability-enhancing attributes of the Sierra All Terrain HD build on the already outstanding capabilities offered in the all-new production Sierra HD trucks,” said Hutchinson. “Although it is strictly aconcept, it is a pretty realistic one.”

Purposeful design

From every angle, the All Terrain HD looks the part of a dedicated off-road performer, with bold, accentuated features complemented by a wide stance and tall profile.

Streamlined bumpers are designed to enhance approach/departure anglesand incorporate frame-mounted recovery hooks – with integrated skid plates. A large, airflow-optimized grille maximizes cooling in tough conditions, while a forced-induction hood delivers more air to the Duramax diesel engine.

“The design of the All Terrain HD is an expression of its capabilities – strong, functional and absolutely professional grade,” said Carl Zipfel, design manager. “We’re excited about the design elements and exploring how they could apply to future GMCs.”

Large fender flares stretch away from the body to cover the 35-inch-tall BFGoodrich tires. At the rear, the cargo box features lockable, lighted storage compartments, along with a number of tie-down cleats, including a pair in the bed floor and two on each side of the bed. A non-slip rubber pad is used on the tailgate, while two special compartments inside the cargo box provide access to a 110-volt power outlet and air compressor. A composite bed liner with a unique “circuit board” pattern provides a protective cover for the bed.

Motorized, deployable assist steps for the cab and cargo bed make it easier to enter and exit the All Terrain HD, while maximizing ground clearance during off-road driving. It also incorporates a number of industrial-grade lighting elements to provide greater visibility for safer driving where stars may be the only other source of illumination. The lighting details include:

High-intensity LED headlamp, taillamp and fog lamp lighting mounted in impact-resistant composite housings and featuring edge-lit illumination
High-intensity LED park and turn signal lamps
Smooth-appearance front marker lamps integrated behind the top edge of the windshield glass
Integrated center high-mounted stop lamp and rear marker lights mounted at the top edge of the rear window glass
LED floodlights for the cargo bed and assist steps.
The All Terrain HD is painted Iridium Metallic – a dark charcoal color that reveals a reddish, anodized inflection when viewed from certain angles. It complements other anodized and satin-metal finishes on the exterior, which give the truck a more precise and functional appearance.

The interior matches the exterior aesthetic, with premium appointments and increased functionality, including enhanced lighting. It conveys solidity and precision, blending accent details such as stainless steel mesh and satin chrome with an amplified expression of the All Terrain’s premium features. Two-tone dark gray leather seats, matched with embossed carbon fiber-style leather on the seating surfaces, have red contrast stitching. Additional leather-wrapped interior features include the steering wheel, instrument panel and center console.

A new navigation radio is also featured on the Sierra All Terrain HD concept and previews future radios to be offered in GMC vehicles. An integrated 80-gig hard drive contains map data for the navigation system. It eliminates the need for a map disc and provides greater storage of music from portable devices. It also features DVR-style “timelapse playback,” which allows up to 20 minutes of recording/playback from the AM/FM/XM radio stations.

All Terrain chassis and suspension

Based on the chassis of the 2011 Sierra HD trucks, the All Terrain HDfeatures a fully boxed steel frame with exceptional strength and torsional stiffness. It incorporates the production models’ new independent front suspension and asymmetrical rear leaf-spring suspensions, but with a wider 73-inch (1,853 mm) track (front and rear) that enhances stability during off-road and highway driving. A production Sierra 2500HD has front and rear tracks of 68.8 inches (1,748mm) and 67.3 inches (1,709 mm), respectively.

An increased ride height provides greater ground clearance of 21.1 inches (536 mm) at the rockers and 11.8 inches (300 mm) at the skid plates, while specialized Fox off-road shocks deliver exceptional damping on tough terrain. They were created specially for the All Terrain HD, with specific valving. The shocks feature visible, remote fluid reservoirs – connected to the shock bodies via custom hoses – mounted in the wheel house liners and are matched with front and rear jounce shocks. They add additional compression damping and more controlled rebound, which helps increase control, stability and handling.

The All Terrain HD also features electronic disconnection of the front stabilizer bar, which enables greater crawling capability on rockyterrain. The driver simply pushes a button inside the cab to disconnectit from the front suspension.

Custom upper and lower control arms for the front suspension are designed to work with the Fox off-road shocks and jounce shocks, while supporting the greater ground clearance and ride height. They contributeto the wider track, as do the aggressive 20-inch machined aluminum all-terrain wheels. The wheels are deep, with six split-spoke elements, and are constructed in a reverse drop-flange method that ensures optimalstrength. They also feature a mix of satin chrome and anodized aluminumfinishes, which provide durability and a premium appearance that complements the body’s Iridium Metallic color.

A full composite underbody protection system shields the All Terrain HD’s transmission, drivetrain, fuel tank, exhaust system and axle differentials. It starts with the front bumper, which rolls beneath the truck and leads to a composite, integral belly pan that covers a front suspension skid plate. Protective covers are also mounted beneath the driveline components, while the front and rear differentials feature direct-mounted skid plates. The rear bumper is integrated with the rear skid plate.

Powertrain details

The Sierra All Terrain HD concept is propelled by the new, production6.6L Duramax turbo-diesel V-8 and Allison 1000 six-speed automatic transmission powertrain combination offered in the 2011 Sierra HD trucks. The Duramax is rated at 397 horsepower (296 kW) and 765 lb.-ft. of torque (1,037 Nm).

The powerful 6.6L Duramax is more fuel-efficient – with up to 11-percent greater fuel economy than previous versions – and reduces NOxemissions by up to 63 percent. The powertrain’s efficiency is assisted by the Allison 1000 transmission, which requires less engine power to funnel torque to the axles. It also incorporates a “smart” exhaust brakefeature that helps save wear on the brakes on downhill grades, a feature available on production Sierra HDs.

With the same proven powertrain as production Sierra HD trucks, the All Terrain HD delivers comparable hauling and towing capabilities, including:

Estimated payload capacity of 2,700 pounds (1,225 kg)
Estimated conventional towing capacity of 13,000 pounds (5,896 kg)
Estimated fifth-wheel towing capacity of 15,600 pounds (7,076 kg).
The Sierra All Terrain HD also features four-wheel drive, with automatic locking front and rear differentials, while the 14-inch, four-wheel disc brake system from the production Sierra HD provides the stopping power for this unique off-roader.

GMC SIERRA ALL TERRAIN HD CONCEPT SPECIFICATIONS

Vehicle:
GMC All Terrain HD concept
Body style / driveline:
5-passenger crew cab, 3/4-ton 4-wheel-drive heavy-duty pickup

Construction:
body on frame

Engine:
Duramax 6.6L turbo-diesel

Horsepower / kW @ rpm:
397 / 296 @ 3000

Torque (lb.-ft/ / Nm) @ rpm:
765 / 1037 @ 1600

Transmission:
Allison 1000 six-speed automatic

Suspension (front):
long- and short-arm independent with torsion bars

Suspension (rear):
semi-elliptic two-stage multi-leaf spring

Steering type:
integral power-assisted recirculating ball

Brakes (type):
power-assisted, Hydroboost brake-apply system, four-wheel disc, four-wheel ABS

Brake rotor diameter x thickness
(in / mm):
front: 13.97 x 1.57 / 355 x 40
rear: 14.17 x 1.34 / 360 x 34

Wheel size and type:
20 x 9.5-inch aluminum

Tire type and size:
BFGoodrich KM2 325/60R20

Wheelbase (in / mm):
148.6 / 3774

Overall length (in / mm):
230.9 / 5864

Overall width (in / mm):
83 / 2106

Overall height (in / mm):
81.8 / 2077

Track – front (in / mm):
73 / 1853

Track – rear (in / mm):
73 / 1853

Minimum ground clearance – (in / mm):
21.1 / 536 (at rocker panels);
11.8 / 300 (at skid plates)

Approach angle – front (deg.):
39

Approach angle – rear (deg.):
31

Maximum payload (lbs. / kg):
2700 / 1225 (est.)

Maximum towing capacity – ball hitch (lbs. – kg):
13,000 / 5896 (est.)

Maximum towing capacity – fifth-wheel hitch (lbs. – kg):
15,600 / 7076 (est.)

Note: Information shown is current at time of publication.

GMC announced today that the all-new 2011 Sierra HD will have a starting price of $27,965, which excludes a $995 destination charge for the 2500 regular cab 2WD model. The Sierra Denali HD, the first offering of the exclusive Denali line on a heavy-duty GMC pickup, will start at $45,865, excluding destination. The new Sierra HDs produced at the Flint Assembly Facility will begin arriving in dealerships in June.

The Sierra HD delivers best-in-class diesel horsepower and torque with the proven and reliable Duramax diesel powertrain and Allison transmission at carryover pricing from 2010 models of $8,395 despite the significant improvements in fuel economy, quietness, emissions and performance. Customers will also benefit from increased towing capability (up to 20,000 lbs./9,072 kg) and payload (up to 6,335 lbs./2,873 kg) that is supported by an all-new fully-boxed, high-strength steel frame for maximum utility and exceptional ride characteristics. The Sierra HD also offers the latest technology in driver confidence and control features such as trailer sway control, a ‘smart’ exhaust brake, hill start assist and more.

“The all-new 2011 Sierra Denali HD blends capability with premium features and styling.” said Lisa Hutchinson, GMC product marketing director. “With its powerful, best-in-class diesel engine, the new Sierra HD models have increased towing and hauling capabilities, a key consideration for people who use them for work or for recreation such as towing a large boat or trailer.”

The Sierra Denali HD is a 2500HD 4WD crew cab. The iconic Denali four-bar, chrome grille with round air inlets distinguishes it on the outside, along with body-color bumpers, chrome door handles, chrome accents and 18- and 20-inch polished forged aluminum wheels.

The 2011Sierra HD lineup has expanded to include eleven 2500HD models and eight single- and dual-rear-wheel 3500HD models offered in WT, SLE and SLT trim levels. A new and larger 36-gallon (136 L) fuel tank is standard on all models. Combined with highway fuel economy improvements up to 11 percent over the previous model, GM testing indicates that the Sierra HD’s equipped with the Duramax diesel can have a highway range up to 680 miles, and new B20 biodiesel capability. The truck also offers the best warranty coverage in America with a five-year/100,000-mile limited powertrain warranty.

GMC today announces the new 2011 Sierra Denali HD, the first offering of the exclusive Denali line on a heavy-duty GMC pickup. The Sierra Denali HD leads a comprehensively redesigned lineup of 2011 Sierra 2500HD and 3500HD trucks that go on sale in early summer – including the most powerful diesel engine in the segment.

Sierra HD’s new 6.6L Duramax turbo diesel delivers 397 horsepower (296 kW) at 3,000 rpm and 765 lb.-ft. of torque (1,037 Nm) at 1,600 rpm.

“The new Sierra Denali HD is the latest expression of GMC’s Denali philosophy of blending capability with premium features and styling,” said Lisa Hutchinson, GMC product marketing director. “It is a premium tool that offers many comfort and infotainment features, along with a maximum towing capacity of 15,600 pounds with the segment’s most powerful diesel – that’s enough to tow a 34-foot-long, three-axle travel trailer.”

The Sierra Denali HD comes exclusively on the 2500HD chassis, in a 4WD crew cab standard box configuration. A Vortec 6.0L gas V-8/six-speed automatic powertrain is standard and the new Duramax 6.6L turbo diesel/Allison 1000 six-speed transmission powertrain is available.

The iconic Denali four-bar, chrome grille with round air inlets distinguishes the Sierra Denali HD on the outside, along with body-color bumpers, chrome door handles, chrome accents and 18- and 20-inch polished forged aluminum wheels.

The balance of the new 2011 Sierra HD lineup is identified on the outside by new, three-bar grilles and powertrain-badged louvered hoods, along with a revised, full-width chrome steel front bumper and a new family of 17-, 18- and 20-inch wheels. It’s beneath the skin, however, where they are truly separated from their predecessors – and the competition. Highlights include:

* Increased towing capability (20,000 lbs./9,072 kg) and payload (6,335 lbs./2,873 kg) supported by all-new fully-boxed, high-strength-steel frames and strong suspensions for maximum capability and exceptional ride characteristics
* Five of the 12 3500HD models offer a payload capability greater than 6,000 pounds vs. Ford Super Duty’s single model greater than 6,000 pounds
* Thirteen of the 22 2500HD models offer a payload capability greater than 3,100 pounds vs. Ford Super Duty’s single model greater than 3,100 pounds
* New 6.6L Duramax diesel delivers segment-best power, up to 11-percent greater highway fuel economy, up to 63-percent lower emissions, B20 biodiesel capability and quicker acceleration
* Larger gas tank and fuel economy improvements allow up to 680 miles (1,090 km) between fill-ups with the 6.6L Duramax turbo diesel
* All-new “smart” exhaust brake feature provides greater control on grades and reduced brake pad wear
* An array of control features, including trailer sway control, integrated trailer brake control, hill start assist, automatic grade braking, intelligent brake assist and larger brakes
* Purposeful technology, including available mobile WiFi, USB connectivity, Bluetooth connectivity, XM Satellite Radio, OnStar 9.0 and navigation.

“GMC has been one of the industry’s strongest truck brands for more than 100 years, and we back the 2011 Sierra HDs with a comprehensive five-year/100,000-mile powertrain warranty that provides the best coverage in America,” said Hutchinson. “From the segment-best diesel power to the segment-best warranty, these trucks deliver strength and peace of mind on all fronts.”

Following are details of the new and redesigned product features of the Sierra Denali HD and the other Sierra 2500HD and 3500HD models.

The Sierra HD lineup brings greater capability.

The details: Depending on the model, Sierra HD models offer:

* Increased fifth-wheel towing capacity of 20,000 pounds (9,072 kg)
* Conventional towing capacity increases up to 23 percent, with a maximum of 16,000 pounds (7,272 kg)
* Improved payload capability of 6,335 pounds (2,873 kg) on a complete vehicle
* Gross Combined Weight Rating increases to 27,500 pounds (12,500 kg)
* Gross Vehicle Weight Ratings increases up to 17 percent to 13,000 pounds (5,909 kg)
* Front Axle Weight Rating increases by up to 25 percent to 6,000 pounds (2,721 kg)
* Snow plow capability for all 4WD cab configurations.

“You can see by the ratings numbers that the Sierra HD lineup is more capable, but the trucks are also better performers in the intangible qualities that bond owners with their trucks,” said Rick Spina, vehicle line executive. “They accelerate quicker – especially when fully loaded – stop more confidently and deliver a smooth, quiet driving experience that you have to experience to fully appreciate.”

The new 2011 Sierra Denali pairs capability with premium features.

The details: The new Sierra Denali HD is offered exclusively in the Crew Cab standard box configuration on the 2500HD chassis, providing a spacious cabin with room for up to five. As with other Denali models, including the new Acadia Denali, the cabin is unique with standard premium touches. It includes Denali-specific brushed aluminum trim, power-adjustable pedals, a Bose premium surround audio system and 12-way power seats. Along with an optional heated steering wheel, heated and cooled leather-appointed seating is available. The exterior is offered in three colors: Black, Stealth Gray and White.

On the capability front, the Sierra Denali has a gross vehicle weight rating (GVWR) of 10,000 pounds (4,536 kg), a payload capacity of 2,959 pounds (1,342 kg) and a maximum trailering rating of 15,600 pounds (7,076 kg) with a fifth-wheel hitch. The maximum conventional hitch trailering rating is 13,000 pounds (5,897 kg).

Engineers developed 11 all-new, fully boxed frame assemblies to improve durability and ride characteristics and support increased capabilities.

The details: The frames have increased cross sections and use more high-strength steel for greater durability, higher towing capacity and improved ride and handling; the front sections are hydroformed. The bending and beaming stiffness of the frames is increased 92 percent and 20 percent, respectively, with the fully boxed sections enhancing torsional stiffness by a factor of five. Also, larger engine and transmission mounts, coupled with a 125-percent-stiffer front frame structure, provide greater vibration control, while hydraulic body mounts are incorporated under the cab section on extended and crew cab models for a more isolated feel inside. Engineers addressed common customer and aftermarket uses when designing the new frames, including adding access holes to the rear frame section to enable easier installation of fifth-wheel/gooseneck-style hitches. Also, the frame-mounted hitch for conventional trailering is stronger, with a box-tube design. It supports up to 16,000 pounds (7,257 kg).

Sierra HDs feature a new, stronger independent front suspension – enabling snow plow installation on all 4WD models.

The details: A completely redesigned independent front suspension system offers up to a 25-percent greater front axle weight rating – up to 6,000 pounds (2,721 kg) front gross axle weight rating (FGAWR) – so a snow plow can be used on all 4WD cab configurations with the available snow plow prep package. Sierra’s signature short-long arm/torsion bar front suspension design is retained, but now features new, forged steel upper control arms that are stronger and lighter than their predecessors. The new lower control arms are made of precision-machined cast iron to handle the greater loads. Five different torsion bar rates support five different front gross axle weight ratings (a single torsion bar was previously used for all models). This helps stabilize the range of trim heights of various models under load, while enhancing appearance, handling, durability, tire wear and alignment. The trim height is adjusted on each bar via a single bolt, easily allowing the height to be changed to account for the weight of a snow plow or other accessories. The Sierra HD front suspension now uses a pair of urethane jounce bumpers on each side, instead of one, for improved load management; and there’s a new upper shock mount attachment design that’s positively connected to the frame with two fasteners. This design eliminates squeaks and clunks, while supporting higher load capability and increased durability.

COMPETITIVE FACTS: Compared to competitors’ beam-axle front suspensions, the Sierra’s independent front suspension provides a better ride, more accurate trim height control (with fewer parts) and greater flexibility to adjust the alignment for weight and tire sensitivity.

A new asymmetrical leaf-spring rear suspension supports greater loads.

The details: Matching the Sierra HD’s greater strength and capability is a rear suspension designed to support greater loads. It features a new, larger asymmetrical leaf-spring design that also contributes to improved ride and handling characteristics. The asymmetrical design is derived from unequal front and rear spring half lengths, which minimize axle hop and enhance traction control efficiency. 2500HD models feature a two-stage leaf-spring design, while 3500HD models have a three-stage design. All models feature 3-inch-wide (76 mm) leaf springs that are 20-percent wider than previous models. The larger leaf-spring design supports increased rear gross axle weight ratings across the board. On the 2500HD models, the rating is 6,200 pounds (2,818 kg) – up from 6,084 (2,765). On 3500HD models, the rating increases to 7,050 pounds (3,204 kg) on single-rear-wheel models and 9,375 pounds (4,261 kg) on dual-rear-wheel models – the latter representing a nearly 14-percent increase over the previous 8,200-pound (3,727 kg) rating.

Sierra HDs deliver a more refined driving experience, with more capable ride, handling and steering.

The details: Longer wheelbases – ranging from 133.6 inches (3,395 mm) to 167.7 inches (4,259 mm) – and wider front/rear tracks enhance the ride and handling characteristics of the Sierra 2500HD and 3500HD, giving them a greater feeling of smoothness and control. The longer wheelbases and wider tracks are complemented by the new, stiffer frames, new jounce bumpers, shock mounts and hydraulic body mounts to provide a solid, smooth and isolated driving experience. New shocks were specially valved to support the new trucks’ weight ratings, while balancing excellent ride characteristics. Also enhancing the driving experience is a revised steering system designed to support the trucks’ greater front gross axle weight rating. It includes a new, larger steering gear, power steering pumps and linkages. The pumps (different parts for gas and diesel models) deliver greater pressure for reduced steering effort in low-speed and parking maneuvers; they are also quieter. On some models, the new linkages feature a compliant joint added at the pitman attachment to enhance handling.

The new 6.6L Duramax turbo diesel delivers segment-leading torque and up to 63-percent lower NOx emissions; and is B20-capable.

The details: The workhorse Duramax 6.6L turbo diesel V-8 is more powerful and durable for 2011, delivering segment-best horsepower and torque – 397 horsepower (296 kW) at 3,000 rpm and 765 lb.-ft. of torque (1,037 Nm) at 1,600 rpm – lower emissions and B20 biodiesel capability that promotes a domestically produced renewable fuel. The new Duramax 6.6L features:

* NOx emissions reduced at least 63 percent over 2010 models
* Quieter operation
* High-pressure (30,000 psi/2,000 bar) Piezo-actuated fuel system for greater fuel efficiency, improved performance and reduced emissions
* “Smart” exhaust brake feature that enables controlled vehicle slowdown on downhill grades without actuating the brakes
* Selective catalytic reduction after-treatment system using diesel exhaust fluid (DEF) 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 have been optimized to provide about 700 miles (1,125 km) between diesel particulate filter regenerations – a 75-percent improvement over the previous system and a significant contributor to improved fuel efficiency, as the regeneration process requires additional fuel
* B20 biodiesel capability for an alternative fueling option
* Internal revisions that improve durability.

With nearly 1.3 million Duramax 6.6L engines produced since 2000, they have proven exceptionally durable and dependable. The internal elements that helped build its reputation are enhanced for 2011, including:

* Main bearings’ profiles changed to enhance oil film thickness
* Oil pump flow increased for increased pressure at low speeds
* Modified turbocharger oil circuit for increased pressure at the turbo and faster oil delivery
* The connecting rods’ pin ends are modified to provide increased piston support
* New, higher-strength piston design that eliminates bushings to provide lower reciprocating weight
* An EGR cooler bypass reduces high-mileage soot deposits in the cooler and EGR circuit.

COMPETITIVE FACTS: Compared with Ford Super Duty’s urea-based system, Sierra HD’s selective catalytic reduction after-treatment system delivers better overall diesel performance, with a range of about 5,000 miles (8,000 km) between DEF refills. Its optimized combustion and after-treatment process provides about 700 miles (1,125 km) between diesel particulate filter regenerations – a better capability than Ford’s.

New Allison 1000 six-speed automatic transmission works with the Duramax 6.6L to deliver greater fuel economy, quicker acceleration, greater towing capability and exhaust brake system.

The details: The enhanced Allison 1000 is strengthened to handle the higher torque capability of the new 6.6L Duramax engine, while also helping to improve fuel economy and provide seamless assistance with a new exhaust brake system. Greater efficiency is delivered through reduced “spin loss” – meaning, the transmission channels more of the engine’s power to the axles, allowing it to do more with less fuel. The Allison 1000 also 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. The six-speed configuration retains its two overdrive gears for optimal efficiency. Performance with the Duramax/Allison combination is also improved over previous models, with preliminary testing showing 0-60 mph times of less than 9 seconds and quarter-mile times of less than 16 seconds in 2500HD models. That’s about 0.3-second and 0.5-second quicker, respectively, than previous models.

A strengthened Vortec 6.0L/Hydra-Matic 6L90 six-speed powertrain is standard in all models.

The details: The Vortec 6.0L gas V-8 with variable valve timing returns to the new Sierra HDs, along with a strengthened version of the Hydra-Matic 6L90 six-speed automatic transmission. This combination delivers excellent performance and efficiency, with a greater emphasis on low-rpm power. It is enhanced for 2011 with greater idle refinement.

The engine is rated at 360 horsepower (268 kW) at 5,400 rpm and 380 lb.-ft. (515 Nm) at 4,200 rpm in trucks with GVWRs up to 10,000 pounds. It is rated at an estimated 322 horsepower (240 kW) at 4,400 rpm and 380 lb.-ft. of torque (515 Nm) at 4,200 rpm in trucks with GVWRs greater than 10,000 pounds.

The 6L90 is enhanced for greater strength, smoothness and quietness via:

* Adding four attachment bosses to the transfer case adapter (4WD models) for increased strength and smoother, quieter performance

* Increasing the cross section size of the transfer case adapter for greater strength
* Adding a new, stronger output shaft
* Adding a new heat shield and vent hose.

COMPETITIVE FACTS: Ford’s new Super Duty models share the same transmission between their gas and diesel engines. Sierra HDs’ Allison 1000 and Hydra-Matic 6L90 transmission were developed for the specific horsepower, torque and operating range differences that distinguish the diesel and gas engines.

Brake feel and performance is greatly improved.

The details: The standard four-wheel disc system is completely revamped to deliver smoother, more immediate and confident-feeling performance. Four-wheel, four-channel ABS is standard on all single-rear-wheel models and a three-channel system is standard on dual-rear-wheel models. The front and rear rotors are larger in diameter – 14 inches (355 mm) – and width on all models to support their increased capacity, weight ratings and trailering ratings, while the calipers are stiffer and stronger. The hydroboost brake booster calibration is revised for reduced pedal effort, and the travel of the pedal is also revised for a more comfortable, confident feel. Larger wheel hub and bearing assemblies complement the new brake system, and the rear rotors attach to the wheel hubs for easier servicing.

Sierra HD’s ‘smart’ exhaust brake feature provides greater control and reduces brake pad wear.

The details: A new standard feature on Duramax-equipped models is the “smart” exhaust brake. This driver-selectable feature uses the turbine control of the variable geometry turbocharger and the compression of the engine to generate backpressure, slowing the vehicle without applying the brakes. It is integrated with the cruise control feature and varies the braking to account for the grade and vehicle load. The exhaust brake allows for virtually effortless driving and towing, with seamless and quiet operation. It also helps prolong brake life and prevents overheating the brakes on long, downhill grades.

Comprehensive safety features and functional technologies include trailer sway control system and hill start assist.

The details: The 2011 Sierra 2500HD and 3500HD models have a comprehensive roster of safety features and functional technologies that include:

* StabiliTrak electronic stability control system on all single-rear-wheel models
* Larger, four-wheel disc brakes with standard four-wheel ABS
* A new high-strength steel tubular frame cross member that enhances safety and improves crashworthiness
* Seat pelvic/thorax and head curtain side air bags available on 2500HD
* Available rear backup camera
* Segment-exclusive OnStar 9.0
* Trailer sway control system on all single-rear-wheel models
* Hill start assist (standard on single-rear-wheel models)

The trailer sway control system provides an added measure of confidence when towing a trailer. The system senses conditions of trailer sway and intervenes with braking and/or reduced engine power to bring the trailer under control and keep it on its intended path. The system uses electric trailer brakes when a trailer is plugged into the standard wiring harness of the truck and its performance requires no input from the driver. The hill start assist system is automatically engaged when sensors detect the vehicle is on a grade of about 5 percent or greater. It holds the brakes for about 1.5 seconds or until the gas pedal is pressed, preventing rollback – it is particularly effective when towing, giving the driver time to switch from the brake pedal to the gas pedal without rolling.

The GMC Sierra HD lineup is broader than ever.

The details: For 2011, the Sierra heavy-duty lineup expands to include 11 2500HD models and eight single- and dual-rear-wheel 3500HD models – including a new 3500HD Crew Cab with a 6.5-foot cargo box. Other models are offered in WT, SLE and SLT trim levels, while popular features such as the EZ Lift tailgate and rearview camera system are retained.

Sierra HD professional-grade interiors are refined and well-appointed – and ready to work.

The details: From the available remote starting feature to the unimpeded access offered by the 170-degree-opening rear access doors on extended cab models, the 2011 Sierra HD models reflect the professional grade blend of refinement and functionality for which GMC is known. The interiors have excellent attention to detail and are quieter – thanks to the range of the truck’s enhancements. The stronger chassis, quieter Duramax engine and even details like a quieter power steering pump contribute to the Sierra HD delivering exceptional quietness.

Along with quietness, Sierra HD models are designed for work. The interiors feature numerous storage compartments, providing covered access for everything from work gloves to laptops. For those who use their truck as a mobile office, Sierra HDs deliver with available mobile WiFi, USB connectivity, Bluetooth connectivity, XM Satellite Radio and a navigation system. Multiple charge points enable multiple electronic devices to operate simultaneously; and when equipped with the available navigation system, XM NavTraffic offers real-time updates of traffic conditions (in selected areas) that can help plan the most effective route to the job site.

Sierra HDs are ready for the long haul – and the cold.

The details: The 2011 Sierra HDs drive farther without stopping to refuel. A new, 36-gallon (136 L) fuel tank is standard on all models and, with the improved fuel efficiency of the powertrains, enables a cruising range of about 680 miles (1,090 km) with the Duramax 6.6L. Cold-weather customers will appreciate the Duramax 6.6L’s quick, reliable start-up, with a starting time on par with gas engines. Its glow plug cycle time is the segment’s best in all temperatures, taking no more than 3 seconds in temperatures as low as -20 F (-29 C). There’s also a cab heat-up feature that allows the engine to idle faster in low temperatures to warm the interior more quickly.

The 2011 Sierra HD lineup has the best warranty coverage in America.

The details: All 2011 Sierra 2500HD and 3500HD trucks work under the best warranty coverage in America: a five-year/100,000-mile limited powertrain warranty, plus roadside assistance, courtesy transportation and other features that provide assurance that GMC backs its trucks for everything the road offers.