A few years ago, the idea of a full-size traditional truck-based SUV averaging 21 mpg seemed about as likely as a Chevy Aveo blowing away a Corvette in the quarter-mile. Normally, you'd be hard-pressed to get 14 mpg in one of these over-5,000-pound beasts. Getting an amazing 50 percent better fuel economy without giving up a powerful V8, eight-passenger capacity and the ability to tow 6,000 pounds might qualify that rig as the eighth wonder of the world. That rig is the 2009 GMC Yukon Hybrid.
It was last year that General Motors achieved that feat, with the debut of hybrid versions of its popular Chevy Tahoe and GMC Yukon twins. Developed in concert by BMW and DaimlerChrysler and General Motors, the Yukon Hybrid's "two-mode" technology starts with a 6.0-liter V8 with cylinder-deactivation technology -- it essentially turns that V8 into a V4 when full power isn't needed. The V8 is coupled to a pair of 60-kilowatt motors packaged within the transmission for electric motivation.
The transmission -- GM dubs it an EVT, for "electronically variable transmission" -- is essentially like having two transmissions inside one -- continuously variable drive for light load conditions and a standard four-speed fixed-gear type for high-load conditions. Hence the term "two-mode." And like other full hybrids, the Yukon Hybrid can be propelled (up to around 25 mph) solely under electric power, which is why its city fuel economy (21 mpg) is virtually the same as its highway (22 mpg). GM did its best to keep the weight gain to a minimum by using aluminum for several body panels and slimming down the seats. (Though ironically, the oh-so-heavy removable third-row seats escaped the liposuction.)
The gains in fuel economy above a regular Yukon's are pretty impressive from a percentage standpoint -- the Hybrid posts an improvement in city mileage of about 50 percent. However, its mid-$50,000 price tag may make you think twice. Other than its sophisticated running gear, the Yukon Hybrid is essentially a fully loaded Yukon SLT, but costs about $8,000 more. Even factoring in federal tax credits, it could take up to a decade to recoup that price premium based on gas savings alone. We'll let you decide if the environmental benefits are worth the price, but how green can a 5,600-pound SUV ever really be?
So, unless the 2009 GMC Yukon Hybrid's significant towing capabilities are important to you, a full-size crossover like the Buick Enclave or GMC Acadia may be a better choice. They provide more usable passenger space, they're friendlier to drive, they get close to the same fuel economy and they're considerably cheaper when fully loaded with options. The new two-mode hybrid system is certainly impressive, but we're not entirely sure if the Yukon is the right vehicle for it.