The biggest change to the 2009 Chevrolet Avalanche is the addition of a new Hyrda Matic 6L80 six-speed automatic transmission, which replaces the long-running 4L60 four-speed unit found in earlier Avalanches, improving highway mileage and reducing engine noise in the process. Under the hood, 2WD models come standard with an iron-block 5.3L OHV V-8 that produces 320 hp and 340 lb-ft of torque. 4WD models will first come standard with an aluminum-block, 5.3L OHV V-8 making 310 hp and 335 lb-ft, and then switch over to an iron-block 5.3L making 320 hp and 340 lb-ft featuring Active Fuel Management, which shuts off half the cylinders under light loads, and Flex Fuel capability, allowing it to run on E85 Ethanol. Both the 2WD and 4WD models can be equipped with an optional 6.0L OHV V-8 that features Active Fuel Management as well as Variable Valve Timing producing 366 hp and 376 lb-ft of torque.

Curiously, though, maximum towing capacity is down by 100 lb to 8100 for the 2WD and 7900 for the 4WD models. The 5.3L models pick up a new standard rear-axle ratio of 3.08:1 for better economy and an optional 3.42 ratio as part of a towing package. Avalanche 6.0L models come standard with a 3.42:1 ratio.

Most of the rest of the 2009 model year changes are on the inside. The last time we had an Avalanche, we thought it was a little light on features and conveniences, but Chevrolet has been remedying that concern over the past few years. The Avalanche has received a much-needed backup camera and rear parking assist, a navigation system, dual-zone climate control, remote starting, rain-sensing wipers, a driver-information center, and a rear-seat DVD entertainment system. For 2009, the Avalanche also gets the latest version of OnStar, Bluetooth connectivity with steering-wheel-mounted controls, a video screen for the backup camera mounted in the rearview mirror for non-navigation-equipped trucks, XM Satellite Radio with NavTraffic for real-time traffic updates, and route planning and an integrated Trailer Brake controller. The Avalanche rolls on standard 17-in. wheels for most 2009 models, with the LTZ trim level getting 20-in. wheels.

The 2LT model gets swankier with a new luxury package that brings heated, 10-way-adjustable power seats with memory to the table, as well as a Bose Premium speaker system, and auto-dimming interior and exterior mirrors. The topline LTZ model gets even more goodies, including 12-way adjustable perforated leather heated seats with memory, Centerpoint Surround Sound Bose speaker system, brushed metal steering wheel trim, "Chevrolet" embossed sill-plates, chrome accents on the sides of the truck, a new rear fascia with more chrome accents and a trailer hitch cover, and new 20-in. chrome wheels.

On the outside, the LTZ model will get a new White Diamond Tricoat paint option, while the whole lineup will get Inferno Orange paint to replace the Sunburst Orange paint option on the previous model year. Dark Brahma Jewel paint will be available in limited quantities toward the end of the model year.

The Z71 off-road package -- with its beefier suspension, big tires, and auto-locking differential -- picks up body-color mirrors and door handles, and a chrome grille insert up front. Inside, Titanium and Cashmere are added to the list of interior colors.

Chevrolet has also gotten serious about safety in its trucks, and the Avalanche is no exception. It comes standard with driver and passenger front airbags, standard side-curtain airbags that stay inflated longer to protect in rollover accidents, a tire-pressure-monitoring system, and the StabiliTrack stability control system with dedicated rollover mitigation technology. The Avalanche also has sensors mounted all around the truck to detect an imminent collision and give the safety systems advanced notice. This system allows the seatbelts to lock before a rear-end collision and keep occupants in place. All models come with GM's OnStar service free for one year, while LT and LTZ models also get the Directions and Connections plan for one year free which features turn-by-turn directions.

Pricing for the 2009 Avalanche starts at $35,910 for the base LS model. The LT model starts at $36,780, while the top-level LTZ model starts at $44,100. The gasoline-only 5.3L V-8 gets an EPA-estimated 14 mpg city and 20 mpg highway, while the FlexFuel 5.3L V-8 gets 10 mpg city and 15 mpg highway. The 6.0L V-8 gets 14 mpg city and 19 mpg highway.