Chevrolet Silverado HD - 2011



Greater towing and payload capability

Stronger frames, suspension systems with greater weight ratings and enhanced powertrain systems contribute to the Silverado HD’s greater towing and payload capability. The specifications charts included below outline capacities for each model and/or configuration, but here are the key facts:

* The maximum conventional (ball hitch) towing rating increases to a segment-best 17,000 pounds (7,727 kg)
* A Silverado 3500HD crew cab/long box can tow up to 21,700 pounds (9,843 kg) with a fifth-wheel hitch
* The maximum payload (3500HD) is 6,635 pounds (3,009 kg).

New 6.6L Duramax diesel and Allison 1000 six-speed combination

Supporting the new 2011 Silverado HD trucks’ greater capabilities is a new version of the workhorse Duramax 6.6L diesel and Allison 1000 six-speed automatic transmission powertrain combination. The Duramax 6.6L is more powerful and durable and the Allison 1000 is stronger and helps enable new features, including the exhaust brake system.

The Duramax 6.6L’s new and improved features include:

* 397 horsepower (296 kW) at 3,000 rpm and 765 lb.-ft. of torque (1,037 Nm) at 1,600 rpm
* 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
* Exhaust brake system 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 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
* The turbocharger’s oil circuit is changed to provide 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.

The enhanced Allison 1000 for 2011 is strengthened to handle the higher torque capability of the new 6.6L Duramax engine, while also helping improve fuel economy and providing 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.

Strengthened Vortec 6.0L/Hydra-Matic 6L90 six-speed powertrain

The venerable Vortec 6.0L gas V-8 with variable valve timing returns to the new heavy-duty trucks, 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.

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.

Exhaust brake system

A new feature on Duramax-equipped models is an exhaust brake system. 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 a smart system integrated with the cruise control feature and varies the braking to account for the grade and vehicle load.

The exhaust brake system 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.


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