2011 Chevrolet Silverado HD (© General Motors)Click to enlarge picture

2011 Chevrolet Silverado HD

In the world of big — really big, manly trucks — Chevrolet had grown a bit long in the tooth. No more, counters the bow-tie brand, with an extensive update of the Chevrolet Silverado heavy-duty pickup for 2011 that focuses on improvements to the engine and chassis. It breaks cover on Wednesday at the Chicago auto show.

Nearly all of the changes are underneath the sheetmetal, and at a glance, this truck looks similar to the previous version. But Chevy had a choice: ladle out the product-development cash or simply focus on what matters for work trucks — the mechanicals. Chevy went with the latter and the result is an improved towing capacity of 20,000 pounds for the Duramax diesel and a top payload of 6,335 pounds for Vortec V8-fitted trucks.

The 6.6-liter Duramax turbodiesel V8, in its fourth generation, is about 60 percent new, with fresh pistons and connecting rods, though the block and heads are carryovers. It also offers a cold-start feature that engineers claim is comparable to a gasoline-powered motor, and no engine-block heater is required until the temperature drops below 20 degrees. The motor works with a six-speed Allison transmission.

The new Duramax diesel has reduced nitrous-oxide output by 63 percent over the previous model and is B20 biodiesel capable.

Left unsaid were the horsepower and torque figures, which are expected to be revealed in the next few weeks after testing is completed. Chevy says they'll be significantly higher than last year, when the Duramax pumped out 365 hp and 660 lb-ft of torque. Fuel economy is expected to improve by 11 percent on the highway, and the new 36-gallon tanks allows for a 680-mile range on the highway.

For gasoline-powered trucks, the 6.0-liter Vortec V8 returns in tandem with the Hydra-Matic six-speed automatic. Look for specs to be close to last year's 360 hp and 380 lb-ft of torque.

The chassis is new, except for two front stabilizer links (the last major chassis re-do was 2001). There's an independent suspension in front, and a 25 percent increase in the front-axle weight rating. There's also an adjustable trim height in front for snow-plow fittings. The rear has an asymmetrical leaf configuration and has been adjusted to handle the increase in torque and any launch shudder. The boxed frame is made of high-strength steel, which Chevy says makes it five times stiffer. Chevy also says all of this makes for improved ride and handling, and it's aiming for best-in-class status.

The Silverado gets plenty of new amenities for 2011, including trailer-sway control, hill-start assist and a smart exhaust brake. The truck also gets bigger brakes with 14-inch rotors (up from 12.8 inches last year) with stiffer, stronger calipers and reduced pedal travel.

Faced with a development budget crimped by the financial difficulties General Motors has endured recently, Chevy opted to keep the cosmetic changes to a minimum and the new truck looks nearly identical to its predecessor. The front is slightly altered for 2011, with a new hood, grille and chrome bumper. The interior is carryover. Look for a sheetmetal redesign in about two years.

Eschewing a new style for elbow-grease substance, Chevy says the new truck is a workmanlike effort pulled off with its workman customer base in mind.

"This is the most expensive tool in their toolbox, or it is their toolbox" said Rick Scheidt, executive director of product and marketing for Chevy trucks.

Engineers spent 500,000 hours testing the truck and are confident it will last for 400,000 miles. The Silverado goes into production in May and is expected to arrive on the market in June.