For 2006, GMC’s full-size Sierra pickup truck undergoes several changes. There’s a new configuration, with extended cab models now available with a short box, in two- or four-wheel-drive, and with a 5.3-litre V8 and available 20-inch wheels. There’s also a new SL crew cab model, in 2WD or 4WD.

Two new packages are available. The Vortec Max Performance Package, with increased towing capability, can be added to 2WD and 4WD extended cab and crew cab models; it includes a high-output 6.0-litre V8, 9.5-inch rear axle and 17-inch wheels. A Sierra Performance Edition can be added to 2WD extended cab models, and includes the high-output 6.0-litre and 20-inch wheels. An additional Sierra Special Edition puts twenty-inch wheels on 2WD or 4WD extended and crew cab models.

The gross vehicle weight rating increases on extended and crew cabs equipped with the 5.3-litre V8, and the Duramax 6600 diesel engine has enhanced horsepower and increased torque. There’s also a new Allison 1000 six-speed tap-shift automatic transmission.

Sierra Hybrid models are now available in a larger market, and the OnStar and satellite radio antennae are a single unit. A power-adjustable manual extendable camper mirror glass is available for increased field of vision. And finally, in the cosmetics department, chrome-clad steel wheels are available for 3500 crew cab long-box models with single rear wheels, and two new exterior colours, Steel Grey Metallic and Stealth Grey Metallic, are added to the palette.

The Sierra, which also appears as the Chevrolet Silverado, comes in a huge number of available configurations. Cab choices are regular, extended or crew cab; engine choices are a 4.3-litre V6, 4.8-litre V8, 5.3-litre V8 and 6.0-litre V8, with three versions of the four-speed Hydra-Matic automatic transmission and two five-speed manual transmissions, one heavy-duty. Heavy-duty truck models feature a 6.0-litre V8, 8.1-litre V8, or 6.6-litre Duramax diesel; transmission choices are a five-speed manual, six-speed manual, four-speed automatic and new six-speed automatic.

Numerous standard and optional features are available for the various models; the Sierra can be taken from a basic work truck to a seriously luxurious asphalt cruiser. As always, GM is locked in a three-way tie with the Ford F-150 and Dodge Ram; the imports, while very good, don’t crack this traditional market easily. The Sierra stands well on its own merits, but its interior looks and feels the cheapest of the bunch.

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