2011 GMC Sierra debuts with new Denali version, more power

GMC is making going to work a bit more stylish--but still with plenty of grunt-- with the first-ever offering of its Denali trim on the Sierra heavy-duty line of trucks.

The 2011 Sierra heavy-duty range was revealed Wednesday in St. Louis at the National Truck Equipment Association Work Truck Show. It goes on sale early this summer.

Like the Chevrolet Silverado HD truck that was revealed at the Chicago auto show, engineers focused on under-the-skin improvements for the Sierra, including to the 6.6-liter Duramax turbo diesel which now makes 397 hp and 765 lb-ft of torque--up from 365 hp and 660 lb-ft in the last model. Towing capacity can reach 20,000 lbs with a fifth wheel. Fuel economy is improved 11 percent.

More than 30 percent of the engine parts are new, including modifications to the cylinder heads and crankshaft and a re-tuned turbocharger. The engine block has also been upgraded with strengthened bulkheads and ribs for noise reduction. It works with a re-done Allison six-speed automatic transmission.

The 6.0-liter small block Vortec V8 has a top payload of 6,335 lbs. It’s rated at 360 hp and 380 lb-ft in the most powerful versions of the Sierra. It’s paired with an updated six-speed Hyrda-Matic transmission.

The trucks also get a new, high-strength, fully-boxed steel frame and re-done suspensions. The frame is five times more rigid in torsional stiffness, the brakes are bolstered to 14-inch rotors front and rear and the suspension is new with a stronger independent layout front and asymmetrical leaf configuration rear.

The Sierra remains GMC’s top seller, making up about 40 percent of its volume.

“Sierra continues to be our cornerstone at GMC, and it will continue to be our cornerstone as long as Americans need strong, capable vehicles for work,” said Lisa Hutchinson, product marketing director for GMC.

The Denali trim adds a flashier chrome grille, chrome door handles and 18-inch wheels with 20-inchers available. Inside is brushed aluminum trim, wood-colored steering wheel and center console and available heated seats and steering wheel. It’s available on the 2500 model.

Other new features include a 36-gallon fuel tank that offers a range of up to 680 miles on the highway, B20 biofuel capability, a tow-haul mode, hill-start assist and trailer-sway program and smart exhaust brake.

“Each of these is aimed at adding increased driver control and confidence,” said Rick Spina, vehicle line executive.

By Greg Migliore