On the road, the Sierra is so quiet and well behaved that it could be mistaken for a luxury car. This is largely due to the chassis (introduced for 1999), whose frame is 23 percent stiffer than that of the previous generation. A cast magnesium beam behind the instrument panel and a lateral steel beam between the magnesium beam and the right side of the dash further reinforce the stiff body. This is a very strong truck, and its strength lets the suspension soak up and manage all the bumps and ruts and tar strips. The extended cab model's 143.5-inch wheelbase improves the ride and enhances high-speed stability.
The 1500 HD 4WD Crew Cab does not ride as smoothly as the Chevy Avalanche, but the ride was reasonably good for what is practically a three-quarter-ton truck with no weight in the bed. Adding some weight back there would undoubtedly smooth it out.
A four-spoke steering wheel connects to rack-and-pinion steering; there is still a fairly wide dead spot in the center when cruising. (GMC says this is intentional, to minimize steering corrections on the highway.) The steering feels a bit light, but the truck tracks beautifully and handles well on pavement, loose dirt, deep dirt and even off-road.
Quadrasteer, the available four-wheel-steering system, works amazingly well. Backing a super-long trailer into a parking space at a 90-degree angle is much, much easier with Quadrasteer than without it. The system shortens turning circles with trailers and makes backing up far more intuitive. On the road, it feels more stable. On winding roads, it's more stable, easier to drive, and the trailer tracks better behind the vehicle. If you tow frequently, you really owe it to yourself to test out a truck with GM's Quadrasteer. Even without a trailer, Quadrasteer makes it much easier to park the truck in tight spaces, such as underground garages and crowded parking lots.
The V6 produces 200 horsepower and a reasonable 260 pound-feet of torque, but most buyers opt for a V8 and automatic transmission.
The 4.8-liter small-block V8 is the most popular engine for this truck, but our Sierra had the larger 5.3-liter (327-cubic-inch) engine, rated 285 horsepower. Its torque peaks at 325 pound-feet, but the torque curve is plenty fat for light towing and hauling. The 5.3-liter engine is also fun for commuting and touring, and we recommend it over the smaller 4.8-liter engine.
The tow/haul mode is a great feature. GM's 4L60-E and 4L65-E four-speed automatics feature a delayed upshift when switched into the tow/haul mode, improving performance while helping the transmission keep its cool. In the tow mode, the transmission holds gears longer before shifting up or down, reducing the tendency of automatics to hunt between third and fourth gears in hilly terrain. When it does shift, the shifts are harder in Tow mode, reducing the amount of time it takes to shift. Both of those strategies reduce heat buildup.
The Sierra 1500 HD can tow trailers weighing up to 10,300 pounds or haul up to 3139 pounds of payload (2837 with 4WD). It comes standard with the Z85 handling/trailering suspension designed to provide a smooth ride. Though the bed is short, it's a great choice for people who tow horse trailers, race cars, or campers. The 6.0-liter V6 that comes standard in 1500 HD models is tuned with considerably more torque in the four-wheel-drive versions (488 pounds-feet) than in the two-wheel-drive versions (360 pounds-feet); the 4WD model trades off horsepower to the 2WD model to do this, however.
Brakes are large, heavy-duty discs on all four corners; ABS is standard on all models. The brakes are huge and powerful and begin to work only an inch into the pedal travel. A feature called Dynamic Rear Proportioning improves stability under heavy braking whether the truck is loaded or empty and can reduce stopping distances. Jam on the brakes and most vehicles without ABS will lock up the rear tires because most of the weight is being transferred to the front wheels. With ABS, the rear wheels won't lock up, but you simply lose some braking performance. With Dynamic Rear Proportioning, the braking performance will be transferred to the tires with the best grip, thereby reducing stopping distances. GMC promises huge improvements in fade resistance, pad life and heat dissipation, and after beating these brakes hard we believe them.
Optional Autotrac four-wheel-drive combines a conventional, truck-style two-speed transfer case with electronic controls. This system allows the driver to lock the axle speeds together in low range for maximum off-road traction; or to select an automatic mode that sends power to the wheels with the best grip. It's a great setup for serious off-road duty, be it mud, deep snow, silt, sand, or rugged terrain.
The Denali features its own full-time four-wheel drive system. A planetary center differential provides a permanent 38/62 front/rear torque split; while a viscous coupling locks up progressively if one axle or the other starts to slip. It's a good system for snow, ice, heavy water, gravel, dirt, or anywhere that presents inconsistent traction conditions.
Denali rides on a uniquely tuned suspension designed to limit body roll (or lean). It also comes with the Z82 towing package, and the high-capacity disc brakes from the Sierra 2500HD/3500.
It's easy and fun to drive the Denali quickly on winding mountain roads. It handles well. It's very responsive for a truck, and it delivers strong acceleration. With its superior towing capability, it might be just the ticket for someone who wants a luxury sports sedan, but has a boat to tow. The all-wheel-drive system will help pull the boat up slippery ramps, while the interior comfort, handling and performance make it an enjoyable and luxurious vehicle around town and on the highway.
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