The 2004 Chevy Avalanche is as big as a Suburban, but handling and performance are surprisingly good. The handling is quite good for such a big, heavy truck, maybe even better than the Suburban. Both 2WD and 4WD versions of the 1500-series Avalanche use the same suspension and ride height, with torsion bars in front and a live axle suspended on five links and coil springs in the rear.Avalanche 1500 models ride as well as a fully loaded Suburban. The Avalanche feels smooth, quiet, and tight, with no squeaks or rattles. The suspension soaks up large potholes and rides comfortably on rough terrain. The brakes were significantly improved for 2003, providing shorter stops, better pedal feel, and quieter operation. GM has come a long way with brakes in the past few years. The new Hydroboost brakes use hydraulic pressure (from power steering fluid) rather than engine vacuum to decrease brake pedal effort. As a result, the Hydroboost system will continue to provide sufficient power assist to stop the vehicle even if the engine stalls or is turned off. The 5.3-liter V8 delivers plenty of punch. It's a responsive engine, rated 295 horsepower and, more important, 330 pounds-feet of torque, which launches the Avalanche quickly off the line. The broad, flat torque curve, with 90 percent of peak torque available from 1600 to 5000 rpm, is designed to provide outstanding trailer-towing and load-hauling capability. A properly equipped Avalanche 1500 is rated to tow up to 8200 pounds. The four-speed automatic transmission (4L60-E) shifts responsively. Pressing the Tow/Haul button results in quicker, harder shifts and reduces heat by limiting the amount of hunting between gears. The 4WD model's Autotrac four-wheel drive lets the driver select different drive modes for different conditions: 2HI drives the rear wheels only and offers the best fuel efficiency. Auto 4WD transfers power from the rear wheels to the front wheels as needed, to optimize traction in inconsistent conditions. 4HI provides the best traction in rugged terrain. 4LO is available for when the going gets really ugly. A neutral position allows the Avalanche to be flat-towed. 2WD 1500 models now offer StabiliTrak electronic traction and stability control. The traction-control function allows acceleration without wheel spin on slippery surfaces. The stability-enhancing function maximizes handling and braking on a variety of surfaces, and is particularly useful in slippery corners. An array of sensors monitor steering wheel angle, wheel speed, brake pressure, longitudinal and lateral acceleration, and yaw rate; a computer uses the data to compare the driver's intentions with the actual direction the truck is headed. The system is programmed to allow for "intervention thresholds," but above that point it steps in whenever one or more wheels is slipping, if the vehicle is slipping sideways, or if it is understeering or oversteering. Then StabiliTrak adjusts engine torque or the brake pressure to individual wheels to help steer the truck back to the path the driver intended. Our advice: If you opt for 2WD, order StabiliTrak.
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