One of the biggest changes for this year is the addition of two new engines to the Silverado HD lineup. A new 6.6L V8 engine is the standard power plant for the two trucks, it makes 401 horsepower and 464 lb-ft of torque and sends power to the rear wheels via a 6-speed automatic, though 4-wheel drive is available. Chevrolet claims that the combination is good for 18 percent more towing capacity when compared to last year's V8 model, thanks to the extra power and torque from the new engine. The optional engine on the Silverado HD is also a 6.6L V8, however this one runs on diesel and is turbocharged. Power maxes out at 445 horsepower, but more important are the 910 lb-ft of torque the engine makes-- enough to tow 35,000 lbs, a 52 percent increase over last year's diesel model. Power is transferred to the rear or all four wheels via a brand new 10-speed automatic transmission. And if owners do spec 4-wheel drive on their Silverado HD, the truck comes with an automatic 2-speed transfer case, allowing for shorter gearing when traveling off-road. The Chevrolet Silverado HD comes in two basic forms, the smaller 2500HD and the larger dual rear wheel setup 3500HD. The most basic trim is simply dubbed Work Truck and comes with all the basics, along with matte black bumpers and 18-inch wheels. For a bit more exterior flash, the Custom trim includes 20-inch wheels and body colored trim details. The LT trim gets additional chrome details on the exterior while the LTZ trim gets even more chrome and LED daytime running lights and headlights. It also gets LED taillights. At the top of the lineup, is the High Country trim which gets its own distinctive front fascia with additional LED lighting and 20-inch polished aluminum wheels on the 2500 or 17-inch polished forged aluminum wheels on the 3500. Chevrolet have determined that the vast majority of Silverado HD customers use their truck for towing and as a result they've concentrated on making the latest generation of the truck the ideal tow vehicle. Standard on the new truck are larger, more functional door-mounted trailering mirrors which can extend and retract manually, or when optioned, via the press of a button. These mirrors also now come with a forward-facing spot lamp and optionally, rearward-facing cameras. An optional tailgate mounted camera and a camera that can be installed in the back of the trailer provide what Chevrolet are calling their "transparent trailer view" which provides huge benefit when taking sharp corners or when trying to maneuver in parking lots. Other technology provided on the Silverado HD to help trailering include an auto park brake assist, an integrated trailer brake controller, an enhanced towing mode that will stay on even if the car is turned off, a trailer sway control mode and an auto grade-braking system that should helps keep things in control when descending a hill while towing.