Following a major redesign 2 years ago, the GMC Sierra 3500HD remains virtually unchanged for 2013. As such, it remains one of the most powerful pickups on the market today, able to tow up to 22,300 pounds with a payload of almost 6,000 pounds. The 2013 GMC Sierra 3500HD has 4 trim levels available: Work Truck, SLE, SLT and Denali. The Sierra 3500HD trims can be configured 42 different ways. All trims are available with either rear-wheel drive (RWD) or 4-wheel drive (4WD). Numerous bed styles are available across all trim levels as well. The Work Truck is available with a long box, extended cab long box, extended cab long box with dual rear wheels (DRW), crew cab and crew cab long box. The SLE is available as a long box, long box DRW, extended cab long box, extended cab long box DRW, crew cab, crew cab long box and crew cab long box DRW. The SLT is available with an extended cab long box, extended cab long box DRW, crew cab, crew cab long box, and crew cab long box DRW. The SLT is available as a crew cab and crew cab long box DRW. The powertrains available for the 2013 GMC Sierra 3500HD are varied as well. The engines available are a Vortex 6.0-liter 16-valve V8 SFI engine with variable valve timing that tops out at 322 hp and 380 lb-ft or torque and a Duramax 6.6-liter V8 turbodiesel engine that makes 335 hp and 685 lb-ft of torque. The engines are matched with a 6-speed automatic heavy-duty transmission, which can be upgraded to an Allison 1000 6-speed automatic transmission. When paired with the Allison transmission, the Duramax engine makes 395 hp and 765 lb-ft of torque. The 2013 GMC Sierra 3500HD runs on standard gas, flex-fuel or diesel, depending on the powertrain package. Fuel economy figures have not been released by the EPA. Standard features found on all 2013 GMC Sierra 3500HD trims include air conditioning, cruise control, a tilt steering column, steering-wheel-mounted audio and cruise controls, power steering, AM/FM radio and 18-inch painted steel wheels with all-season tires. Available options on some trims include a leather-wrapped and heated steering wheel, adjustable foot pedals, leather seats, heated and cooled front seats, power adjustable front seats, CD player with 6-CD changer, navigation system, moonroof and 17- or 18-inch aluminum alloy wheels with all-season tires. Standard safety and security features found on all 2013 GMC Sierra 3500HD trims include driver's and front passenger head curtain airbags, 4-wheel antilock disc braking system with electronic brakeforce distribution and emergency braking assist, stability control, traction control, daytime running lights and engine immobilizer. With 42 different configurations available, the 2013 GMC Sierra 3500HD makes it possible for a buyer to design the truck that best fits his or her needs. The large towing capacity and payload that the Sierra 3500HD can handle makes it one of the premier options in the heavy-duty pickup truck class, competing on an even playing field against such competitors as the Chevrolet Silverado HD, Ford Super Duty and Ram Super Duty. While the performance marks for some of the competition may be slightly higher, the Sierra 3500HD more than makes up for it in quality and available options.