Overview

What's new
Sierra Classic HD represents the heavy-duty version of the Sierra Classic line of full-size pickup trucks. The "Classic" designation refers to the conventional-styled truck dating back to 1999 and differentiates it from the new, redesigned Sierra line that is concurrently offered for 2007. There are no significant changes to the Sierra Classic HD as it enters its final year of production.

Overview
Sierra Classic HDs carry over the "classic" design GMC has offered for nearly a decade. Primary models are the three-quarter-ton 2500HD and 3500, although GMC also offers a half-ton 1500 HD. Trim levels are SL, SLE, and SLT, plus a 2500HD-exclusive WT (Work Truck) trim. Three cab types are available: 2-door regular cab, 4-door extended cab with smaller rear access doors, and a crew cab with four full-size doors. Regular cabs come with an 8-foot cargo box, while extended and crew cabs also offer a 6.5-foot bed. Four-wheel drive is available, and the 3500 also offers a dual-rear-wheel version.

The 2500HD and 3500 offer three engines; the base engine is a 6.0-liter V-8 with 300 hp (the same and only engine offered on the 1500HD). Those desiring more power can opt for a 330-hp, 8.1-liter V-8 or an even more potent 360-hp, 6.6-liter Duramax turbodiesel V-8 that offers a whopping 650 lb.-ft. of torque. As for transmissions, the standard 6.0-liter comes with either a 5-speed manual or an optional 4-speed automatic with Tow/Haul mode. The two larger engines give you a choice between a 6-speed manual and an optional Allison 5-speed automatic. The Allison features Engine Grade Braking that automatically downshifts when descending steep slopes. For 2007, GMC is backing its powertrains with a 5-year/100,000-mile warranty.

All Sierra Classic HDs come standard with dual dashboard air bags, however side curtain air bags are not offered. Anti-lock 4-wheel disc brakes are also standard. Notable options include XM Satellite Radio, a power sunroof, power-extending camper mirrors, lockable underseat storage on extended cabs, and a rear-seat entertainment system for crew cab models.

The Competition
The GMC Sierra Classic HD competes in the Large Pickup segment, which consists of seven models. Buyers in this segment look for performance, comfort, and reliability, according to the J.D. Power and Associates 2006 Avoider Study^SM and the Escaped Shopper Study.^SM

The top sellers in the segment during calendar year 2006, according to the J.D. Power and Associates Sales Report,^SM were the Ford F-Series (764,198 units sold, including Super Duty models), Chevrolet Silverado (636,069, including Heavy Duty, classic, and Classic HD models), and Dodge Ram Pickup (364,177, including Heavy Duty models). The GMC Sierra Classic HD sold 210,736 units (including light- and heavy-duty models) in 2006, a decrease of 8.2 percent compared to the previous year. Other models offered in the Large Pickup segment include the Toyota Tundra, Nissan Titan, and Chevrolet Avalanche .