2011 GMC Sierra Denali HD revealed

Article by Christian Andrei, on August 27, 2010

The 2011 Sierra Denali HD pickup was launched at the National Truck Equipment Association Convention in St. Louis. Dealerships will be receiving this car starting in the early summer. General Motors Co.'s GMC division said that this pickup is the sibling of the heavy-duty Chevrolet Silverado, which was unveiled at the Chicago Auto Show.

The all-new Sierra Denali HD is powered by the 6.6-liter Durmax turbo diesel engine, the most powerful unit currently offered by the carmaker.

GMC officials claim that this new engine can deliver 397hp and 765 pound-feet of torque. It's pitted against Ford Motor Co.'s all-new 6.7-liter V-8 diesel engine, which generates 385hp and 735 pound-feet of torque. 

In a news release, Lisa Hutchinson, GMC product marketing director, described the new Sierra Denali HD as "the latest expression of GMC's Denali philosophy of blending capability with premium features and styling." GMC will also be offering a 6-liter V-8 gas engine, which has an output of 360hp and 380 pound-feet of torque.

The new GMC heavy-duty trucks are capable of providing up to 20,000 pounds towing capacity and up to 6,335 pounds payload capacity.

The new Duramax engine, which is partnered with an Allison six-speed automatic transmission, will also get an 11% fuel economy improvement, as well as 63% lower emissions.

GM's heavy-duty pickups will also be updated to include a stronger fully-boxed frame, among other improvements.

There's a lot happening with the pickup market as both Ford and GM are launching all-new heavy-duty trucks for the 2011 model year. Chrysler Group LLC is also set to offering its new heavy-duty truck any day now.

Press Release

GMC Sierra HD/Denali HD - 2011

de confidence to manage the heaviest loads
Best warranty coverage in America

GMC Sierra Denali 2500HD and 3500HD – the first offerings of the exclusive Denali line on a heavy-duty GMC pickup – lead a new Sierra heavy-duty truck lineup for 2011.. The comprehensively redesigned roster of 2011 Sierra 2500HD and 3500HD trucks includes a new, more powerful 6.6L Duramax turbo diesel that 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 21,700 pounds with the more powerful Duramax diesel.”

The new Denali HDs are crew cabs available only in the 2500 series (3/4-ton), 2WD and 4WD configurations, as well as the 3500 Series (1-ton) 2WD and 4WD in both single-rear-wheel and dually versions. The 3500 series is also available in standard (6-foot 6-inches) and dually long box (8-foot) versions. 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 on all Denali HDs.

The iconic Denali four-bar, chrome grille with round air inlets distinguishes the Sierra Denali HDs on the outside, along with body-color bumpers, chrome door handles, chrome accents and 17- (Dually), 18- and 20-inch polished forged aluminum wheels. On the inside they include 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.

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:

Greater towing capability (21,700 lbs./9,843 kg) and payload (6,635 lbs./3,009 kg) supported by all-new fully-boxed, high-strength-steel frames and strong suspensions for maximum capability and exceptional ride characteristics
New 6.6L Duramax diesel delivering more 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 for up to 680 miles (1,090 km) between fill-ups with the 6.6L Duramax turbo diesel
All-new “smart” exhaust brake feature for 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
Consumer-focused 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 greater diesel power to the segment-best warranty, these trucks deliver strength and peace of mind on all fronts.”

The following pages provide details of the new and redesigned product features of the Sierra Denali HD and the other Sierra 2500HD and 3500HD models.

Greater capability

Depending on the model, Sierra HD models offer:

Segment-leading fifth-wheel towing capacity of 21,700 pounds (9,843 kg)
Conventional towing capacity increases to a segment-best 17,000 pounds (7,711 kg)
Improved payload capability of 6,635 pounds (3,009 kg) on a complete vehicle
Segment-leading Gross Combined Weight Rating increases to 29,200 pounds (13,244 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.”

Eleven all-new, fully boxed frame assemblies improve durability and ride characteristics; and support increased capabilities.

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 17,000 pounds (7,711 kg).

New, stronger front suspension enables snow plow installation on all 4WD models.

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.

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.

New, asymmetrical leaf-spring rear suspension supports greater loads.

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.

The 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.

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.

A revised steering system designed to support the trucks’ greater front gross axle weight rating also enhances the driving experience. 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.

New 6.6L Duramax turbo diesel

The workhorse Duramax 6.6L turbo diesel V-8 is more powerful and durable for 2011, delivering 397 horsepower (296 kW) at 3,000 rpm and 765 lb.-ft. of torque (1,037 Nm) at 1,600 rpm. It also produces lower emissions and offers 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 that 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.
The nearly 1.3 million Duramax 6.6L engines produced since 2000 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
Modified connecting rods’ pin ends to provide increased piston support
New, higher-strength piston design that eliminates bushings to provide lower reciprocating weight
An EGR cooler bypass that reduces high-mileage soot deposits in the cooler and EGR circuit.
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.

New Allison 1000 six-speed automatic transmission

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.

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

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.
Brake feel and performance is greatly improved.

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 revised hydroboost brake booster calibration reduces pedal effort, and the revised travel of the pedal provides 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.

‘Smart’ exhaust brake provides greater control and reduces brake pad wear.

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.

Safety features include trailer sway control system and hill start assist.

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.

Broad lineup – inside and out.

For 2011, the Sierra heavy-duty lineup expands to include 12 2500HD models and nine 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.

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.

Ready for the long haul – and the cold.

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 best warranty coverage in America.

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.

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