The 3500, though a few pounds short, represents the one-ton offering in the GMC pickup lineup. When fully equipped, the 2005 GMC Sierra 3500 can tow up to 12,000 pounds. It receives few changes this year, aside from an optional package that bundles a sunroof, garage opener, and overhead console for Extended and Crew Cabs. Also new is a power upgrade for the 6.6-liter turbodiesel Duramax to 310 and 605 lb-ft of torque when mated to the 5-speed Allison auto tran. The Sierra 3500 comes as a rear-wheel or four-wheel drive, with either dual rear or single rear tires. Trim options start with the basic Work Truck and move up through Base, SLE, and SLT, adding power features, cruise control, and leather along the way. Cab lengths are Regular (seats three in one row), Extended, and Crew (seats six in two rows). Standard engine is a 6.0-liter, 300-hp V8, matched to a 4-speed automatic or 5-speed manual. A third engine choice is the 8.1-liter, 300-hp V8 with 450 lb-ft of torque that couples with either the Allison or a 6-speed manual. 16-inch wheels are standard, but 4WD models can be equipped with 17-inch wheels. Other standard features include ABS brakes and dual front airbags. Despite gussying it up in creature comforts offered by the SLT, the 2005 GMC Sierra 3500 is a workhorse through and through, and owners love the powerful powertrain and hauling capacity of this pickup. Though not as big a seller as the Ford F-Series, when combined with the Silverado, it surpasses Ford in sales. Drivers also like the interior space, but not the plastic materials. A wide turning radius and low gas mileage also doesn't win fans.