GMC YUKON HYBRID FOR CARS

The GMC Yukon Hybrid, and its counterpart the Chevy Tahoe Hybrid, are the first vehicles to utilize the advanced two-mode hybrid powertrain developed jointly by BMW, DaimlerChrysler, and General Motors. This full-size SUV launches a new breed of larger vehicles that are significantly greener than their gas-powered versions.

The core of the Tahoe Hybrid’s powertrain is GM’s 6-liter Vortec V8 with cylinder deactivation technology. In other words, this engine can shut down four of its eight cylinders when the additional power is not needed. That saves fuel. Beyond the engine, there’s a 300-volt battery that hides below the second-row seats. The vehicle's two electric motors are housed within the transmission.

To drop the Yukon Hybrid's aerodynamic Cd from .39 to .34, GM re-softened those sharpened creases with a slightly reshaped hood and rear hatch, and lost the roof rack. Although the new hood and hatch are fashioned from aluminum, the Yukon Hybrid's batteries and electric motor make it heavier than the standard model. The Yukon Hybrid's heft rises from either 5270 to 5541 lbs., or from 5438 to 5617 lbs., depending on whether you believe GM PR or the GMC website.

GM's new truck interiors may be far better than anything they've ever offered, boasting attractive chrome accents and a real woven headliner. But at $51k (base), the Yukon Hybrid's interior feels cheaper than a Las Vegas motel on a Tuesday afternoon. Fake wood and aluminum abound. Vinyl that tries (and fails) to look like leather stretches across the ample dashboard. The seats are flat and unsupportive, and the optional third row seat is unusable for anyone but Hobbits.

The Hybrid comes amply-equipped with navigation, rear parking camera, auto climate control and power everything. In complete contrast to the exterior, only a small Hybrid logo, an "Eco" gauge and a Prius-like touch screen drivetrain display remind the driver that they're piloting the world's largest private passenger hybrid.

To maintain the Yukon's cavernous interior, the engineers utilized the undercarriage space for the NiMH batteries. Part of that space was realized (and the beast's weight gain minimized) by replacing the full-size spare tire with a can of sealant– not exactly what you'd expect in a 4×4. Not that you'd ever take those low-rolling-resistance donuts off-road. On the positive side, the Yukon Hybrid 4X4's towing capacity is a respectable 6000 lbs. (down from 8000 lbs.).

Which may account for GM's decision to equip the Yukon Hybrid with a 332hp, 6.0-liter Vortec engine. In any case, the monster motor becomes a hybrid with the addition of a 300V battery, two 60KW motors in the transmission and some creative software.

I've never driven a full hybrid this seamless in operation. You never notice when the drivetrain changes modes, from electric to gas and back. The electric boost comes on smoothly; the power delivery remains silken as the engine spools-up. When revved hard, the 6.0-liter offered a muted yet spine-tingling burble. Despite the weight, the excellent drivetrain pushes the Yukon from zero to sixty miles per hour in about eight seconds. The system manages a decent-for-such-a-behemoth 20mpg both in the city AND on the highway.

The Yukon Hybrid's suspension is as ridiculous as the drivetrain is sublime. The steering feels vague at low speeds and darty on the highway. Engaging four-wheel-drive mode makes the rig feel like a forklift, with all four wheels pushing in different directions. The Yukon skitters and wallows during cornering and shudders like a Sebring convertible over rough patches. The massive weight smooths out the ride to decent levels, but the European and Japanese competition put the Yukon to shame in comfort, control and cornering ability.

As for that highly-touted 25 percent fuel economy improvement, yes, I achieved the advertised mpg in mixed driving. But I wonder how much of that gain's down to the non-drivetrain mods. Equally perplexing: why hasn't GM incorporated them into normal Yukotahburbelades? Is the American automaker shortchanging their gas-powered SUVs to protect the hybrid versions' rep? Clearly, the Yukon Hybrid raises more questions than it answers. Meanwhile, one thing is for sure: at that price, in this market, the Yukon Hybrid will not be flying off the lots.

The Yukon Hybrid grants plenty of capability for work-related endeavors, and an abundance of space and amenities for large families, even up to eight.