First Test: 2012 Chevrolet Avalanche LTZ 4WD

The truck and SUV market has undergone some major changes over the last two decades, during which time, we've seen a lot of models and interesting concepts come and go. One of the most innovative was the Chevrolet Avalanche. While in production for more than a decade, the Avalanche, and its uptown cousin, the Cadillac Escalade EXT, are hardly rare, and the curtain is about to come down on this unusual hybrid of a full-size truck and SUV.

No direct full-size competitor to the Avalanche and Escalade EXT ever emerged, but several smaller midsize models closely emulated the Avalanche's style and configuration -- even within General Motors itself, in the form of the GMC Envoy XUV in 2004. The Ford Explorer Sport Trac predated the Avalanche by one model year, and the Honda Ridgeline debuted in 2005, looking to many like a slightly smaller Avalanche. Only the Envoy XUV shared the Avalanche's innovative Midgate, which extended the cargo area into the passenger compartment.

Of these interesting variants, only the Ridgeline remains in production, and Honda has lately been on the defensive about the future prospects of the modestly selling midsize utility.

See All 6 Photos6

The Avalanche in its current form has been around since the 2007 model year, joining the Tahoe and Suburban with the GMT-900 series SUV makeover. The last major change came in 2009 with the introduction of the 6L80 six-speed automatic transmission, helping the Avalanche gain 1/2-mpg city/highway ratings, giving it a 15/21 mpg city/highway rating for the 2012 4x4 model. Along with the switch to the six-speed transmission, the previously optional 6.0-liter Vortec V-8 was also dropped, leaving GM's ubiquitous 5.3-liter, 320-hp Vortec V-8 as the sole engine offering.

Even after 5 years with the same basic design and configuration, nothing about the Avalanche feels particularly dated or out-of-sync with current full-size SUV offerings. The attributes that applied to the GMT-900 SUVs at their launch also apply today, namely, well-isolated wind and road noise and a compliant, comfortable ride.

Interior ergonomics are also about par for the class, the only major complaint being that the navigation and information-control unit touchscreen is mounted too low for ready visibility. Also, there's more hard plastic than we'd like, especially at our LTZ tester's $53,815 price. Still, it's not unattractive, and if you're really insistent on soft-touch materials, you can always pop for the aforementioned Escalade EXT.

The six-speed transmission makes the Vortec 5300 V-8 feel more sprightly than did the previous four-speed, but the two extra ratios still can't mask the engine's slightly peaky power and torque delivery, especially considering the Avalanche's 3-ton weight. Our tester never felt underpowered per se, but the engine needed to rev a little higher than expected to deliver power for merging or passing. Our test numbers reflect the slight power deficit for such a heavy vehicle, with unremarkable 8.6-second 0-60-mph and 16.7-second quarter-mile runs.

See All 6 Photos6

The pervasive heft that gives the Avalanche its sense of refinement and isolation also discourages overly spirited driving. The steering is deliberately heavy, but direct. The only aspect of the Avalanche's driving experience that occasionally invites juvenile antics is the V-8 engine's muscular, throaty growl at wide-open throttle. The irony of the engine's peaky power delivery is that owners may be hearing the sound often, but with that sweet, timeless small-block sound, few will likely object.

If the Avalanche's unique combination of versatility and comfort appeals to you, there's a last chance to buy one new, with the Black Diamond edition for 2013, intended as a last-year tribute to GM's bold full-size SUV experiment. Cadillac has yet to announce official directions for the Escalade EXT, but all indications point to the end of the line for the uptown variant as well.

What has spelled the end for the Avalanche? As with many models, it comes down to sales. Although arguably a better, more advanced and more refined model all-around, the second-generation GMT-900 Avalanche never approached the sales numbers of the first-generation, which peaked in 2003, and were on a downward trajectory well before the 2007 model hit showrooms. Fullsize SUV sales were already declining, and customers were beginning to seek smaller, more fuel-efficient models.

Although it's fun to armchair-quarterback the "what ifs" of the Avalanche with GM's stillborn "baby" 4.5-liter Duramax turbodiesel, the model's days were likely numbered regardless of powertrain. As it is, the Avalanche stands as a unique example of General Motors' innovation in the SUV segment just as the storm clouds were beginning to form on the horizon for full-size SUV sales.

See All 6 Photos6