Ken Nelson Auto Group

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Driving Impressions

The GMC Sierra HD raised the bar in ride quality and refinement when redesigned for the 2007 model year, and minor upgrades since improve on that. It will not ride like a car, nothing that can haul another car does, but it may spoil you for older pickups.

The 6.0-liter V8 gas engine has broadly the same horsepower as the old 8-liter big-block, but torque is down roughly 75 lb-ft. Torque is what gets any load moving, up to about 45 mph, and helps keep it moving on grades. On the other hand, the six-speed transmission makes up for a lot, so the absence of a big-block is most noticed in low-range 4WD and the less-forceful shove in your back when you leave a traffic light. The 6.0-liter and six-speed automatic will do about 90 percent of what the big-block 8.1-liter gas engine and four-speed automatic did. And the 6.0-liter will use less gas in the process. The 6.0-liter V8 features an iron block for durability and variable cam timing for efficiency. The 6.0-liter V8 rates 360 hp and 380 lb-ft of torque. It rates 322 hp for GVWR above 10,000 pounds, making the diesel even more attractive for dual-rear-wheel models.

The 6.6-liter turbodiesel option blows the 6-liter gas engine into the weeds for pulling power and fuel economy, though you might say for about $8400 for the powertrain it ought to. Called Duramax, the diesel engine boasts 660 lb-ft of torque available at a much lower engine speed and 365 horsepower. It meets the latest emissions requirements for diesel engines, with reductions of 90 percent in some cases, and the diesel exhaust pipe stays clean and steel-colored inside where the gas engine's pipe is black. The latest generation of induction systems has made the diesel much quieter; your riders may not know it's a diesel if you don't tell them. (The Duramax is approved for B20 biodiesel only in fleet use.)

Pickups of yore tended to buck like broncos on uneven surfaces like turnpike expansion joints, with the bed trying to bounce one direction and the cab the other. Often a function of wheelbase, this can't be completely eliminated in a long vehicle like a Sierra HD, but quality build and engineering does an admirable job of mitigating the motion.

There's heft to the feel of a Sierra, from the way it takes big bumps to the steering and throttle inputs. Its handling characteristics are benign and amount to basic plowing if you push too hard. All-terrain tires give better grip on dirt roads, at the expense of steering precision and noise on tarmac.

Like all big 2WD pickups the Sierra uses all-vented disc brakes with ABS, and independent front suspension. However, only the GM heavy-duty pickups use the same design on 4WD models, giving them a lower nose and more responsive steering. Again, like any big pickup, the tail is prone to kick over impacts with an empty bed; the Sierra is similar to others although it may feel it has more kick because the front is softer.

The optional integrated trailer brake controller will apply your trailer brakes smoother than any aftermarket controller and works in concert with the Sierra's braking system. This controller, however, is not compatible with all brands of electric-hydraulic disc brakes.

The 2.5-inch receiver hitch allows conventional trailer ratings to 13,000 pounds, higher than many competitive offerings; the maximum for fifth-wheels 16,500 pounds. The strongest Sierra HD will haul 23,500 pounds gross combined: the truck, fuel, passengers, cargo, and loaded trailer.

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