Following a major overhaul for the 2011 model year, the GMC Sierra 2500HD returns for 2012 with only minor modifications, such as the addition of a hard-drive-based navigation system and heated ventilated seats for the more expensive trims, as well as offering the new Denali trim. For 2012, there are four trim levels available for the GMC Sierra 2500HD: Work Truck, SLE, LTZ and Denali. Each trim level can be configured with a Regular cab with a long box (8 feet in length), an Extended cab with a standard (6.6 feet) or long box, or a Crew cab with a standard or long box, except for the Denali, which is available only with a Crew cab and a standard box. All trims can be equipped with either rear-wheel drive (RWD) or 4-wheel drive (4WD), but all come standard with a 6.0-liter 16-valve OHV V8 Flex-Fuel engine paired with a 6-speed heavy-duty automatic transmission with overdrive that achieves 360 hp and 380 lb-ft of torque. However, an available 6.6-liter Duramax turbocharged V8 diesel engine that is biodiesel compatible, married to an Allison 1000 6-speed heavy-duty automatic transmission with overdrive, is available for all trims and gets 397 hp and 765 lb-ft of torque. As of press time, none of the Sierra 2500HD trims' mileage had been rated by the EPA. The 2012 GMC Sierra 2500HD Work Truck trims come equipped with single-zone manual air conditioning, cruise control, power steering, manual folding exterior mirrors, vinyl seats, a front split bench seat, chrome bumper, AM/FM stereo, front intermittent windshield wipers and 17-inch steel wheels with all-season blackwall tires. The SLE trims add power door locks, power windows, heated power-adjustable, manual folding exterior mirrors, a leather-wrapped steering wheel, premium cloth seats, manual adjustable driver’s seat, 4-speaker sound system (6 speakers in Extended and Crew cab trims), AM/FM radio with CD/MP3 player, Sirius XM satellite radio with a 3-month trial subscription, OnStar Directions and Connections with a 6-month trial subscription, a chrome grille with chrome surround and 17-inch machined aluminum alloy wheels with all-season blackwall tires. Upgrading to an SLT trim adds or substitutes dual-zone automatic air conditioning with climate control, heated power exterior mirrors, leather-appointed front seat trim, heated and cooled front bucket seats, a heavy-duty trailering package, heavy-duty automatic locking rear differential, Bluetooth HandsFree capability, a USB port, remote start and 18-inch forged polished aluminum alloy wheels with all-season blackwall tires. The Denali trim is equipped similar to the SLT trim, but adds a heated leather-wrapped steering wheel with audio and cruise controls, power adjustable pedals, rear window defogger, remote vehicle start, rear 60/40 folding bench seat, a rear-view camera, ultrasonic rear parking assist, a 7-speaker Bose premium sound system with AM/FM radio and an MP3-compatible 6-CD player, an EZ-Lift locking tailgate, dual halogen composite headlights and front fog lights. Options available on the various trims include a power sunroof, bedliner, splash guards, hard tri-folding tonneau cover or soft cloth folding tonneau cover, auto-dimming rear-view mirror, power-sliding rear window, rear seat audio system controls, CD/DVD/MP3 player—with or without a hard-drive navigation system and Sirius XM NavTraffic, rear seat entertainment package, engine block heater, 20-inch forged polished aluminum alloy wheels and 18- or 20-inch all-terrain blackwall tires. Not all options are available for all trim levels. Several safety and security features come as standard equipment on the 2012 GMC Sierra 2500HD, including dual-stage frontal driver and right-front passenger airbags (head curtain side-impact airbags and seat-mounted side-impact driver and right-front passenger airbags are options available for Work Truck and SLE trims), a tire pressure monitoring system, 4-wheel antilock disc brakes with intelligent brake assist, StabiliTrak traction control with proactive roll avoidance, trailer sway control and hill start assist, OnStar Directions and Connections with a 6-month trial subscription and daytime running lights. Competing against three-quarter-ton pickups such as the Ford Super Duty F250 and Ram 2500, as well as its chassis-mate the Chevrolet Silverado 2500HD, the 2012 GMC Sierra 2500HD fares well when it comes to powertrain, handling and towing capacity (up to 13,000 pounds when properly equipped). While it does not lead in any one category and can get a bit pricey in upper trim levels, the Sierra 2500HD is a strong overall performer and a solid choice for a heady-duty pickup.