Used 2008 GMC Yukon

While Toyota and Honda are busy building small, relatively affordable hybrids, GM is taking a different track, working to improve the fuel efficiency of its most popular sedans and SUVs. The logic may pass over die-hard environmentalists, but from the typical American family’s point of view, it makes perfect sense. Many families need the interior accommodations provided by a full-size SUV, not to mention its ability to tow a boat or horse trailer. By creating a hybrid version of its full-size Yukon and Tahoe SUVs, GM has built two vehicles that can seat eight, tow up to 6,200 pounds yet achieve the same city fuel economy ratings as the four-cylinder Toyota Camry.

If not for the Auto Stop meter and hybrid control system readout, you might never know the Tahoe Hybrid was anything more than, well, a Tahoe (or Yukon). The shift between electric power and the gasoline engine is seamless, as is the Active Fuel Management’s switch from eight cylinders to four. In short order, the driver learns how to keep the gas engine shut down, relying on the electric motors to do most of the work. This is possible when accelerating from a standing stop and traveling at speeds under 25 miles per hour. A manual shift mode and a regenerative braking system, when properly engaged, allows the driver to recapture energy and replenish the batteries. The fuel economy game is addictive and by feathering the throttle and keeping our speed below 30 miles per hour, we were able to attain 22.7 miles per gallon in stop-and-go city driving.

The most noticeable changes from the standard Tahoe and Yukon can be seen on the dash, where the DVD navigation screen doubles as a display for the hybrid power system readouts. Behind the steering wheel, a revised instrument cluster plays home to a unique tachometer designed to inform the driver when the Auto Stop feature engages. In Auto Stop, the gasoline engine shuts down and the Hybrid is propelled solely by the electric motors built into its transmission. An analog economy gauge also helps to maximize fuel consumption. In a nod to further weight reduction, the Yukon and Tahoe Hybrid’s specialized interiors feature lighter, thinner seats that actually add 1.5-inches of second-row passenger knee room.

Other than some minor cosmetic changes, there is little to differentiate the GMC Yukon Hybrid from its Chevrolet twin. Compared with their gasoline-powered equivalents, the Hybrids sport a different front end where a lower air damn that reduces drag replace the traditional fog lamps and tow hook openings. Wide openings in the grille help cool the advanced hybrid power electronics, and the hood is fashioned from aluminum. The Yukon features larger vertically stacked headlights and the traditional GMC grille, while the Tahoe’s front end is a bit more reserved. Continuing rearward, the Hybrids delete the standard roof rack side rails and replace the rear liftgate with a one-piece aluminum door featuring a fixed glass window. An extended rear spoiler improves aerodynamics, as do the sharp-edged D-pillars (color-keyed on the Tahoe, black on the Yukon). Other mass-saving features include the adoption of a tire inflator kit, which eliminates the traditional spare tire, jack, hoist and tools found on non-hybrid models.

Electrically Variable Transmission
This marvelously compact system is actually incredibly complex, allowing for seamless power transfers between the gasoline engine and electric motors. The unit is also responsible for varying gear ratios when towing or accelerating and for recapturing energy during braking and deceleration.

Lightweight Seating
Although noticeably thinner than the standard Yukon and Tahoe seating, the Hybrid twin’s equally comfortable seats actually create more legroom for second-row passengers.

The 2008 Chevrolet Tahoe and GMC Yukon Hybrid feature a 6.0-liter gasoline engine with Active Fuel Management, two-mode Electrically Variable Transmission (EVT), head-curtain airbags covering all three rows, tri-zone automatic air conditioning, rearview camera system, powerfolding heated side mirrors, electric power steering, side-mounted assist steps, rear park assist, 18-inch lightweight wheels, leather seating, six-way power driver’s seat, Bose nine-speaker audio system, XM Satellite Radio, DVD navigation and rear-seat audio controls.

The Tahoe and Yukon Hybrids are pretty well equipped, leaving only a few notable options. Owners can add a power glass sunroof, engine block heater, rear seat DVD entertainment, locking rear axle, six-disc MP3 compatible CD changer and four-wheel drive.

The 2008 Chevrolet Tahoe and GMC Yukon Hybrids are equipped with a 6.0-liter V8 engine with GM’s Active Fuel Management system. AFM cuts fuel to four of the eight cylinders when not required. The two-mode Electrically Variable Transmission, or EVT, employs two powerful electric motors housed inside the transmission casing. These units add additional torque when required and, under the right conditions, can actually move the Hybrid without the gasoline engine’s assistance. The electric assist also allows the gasoline engine to run in four-cylinder mode more often, saving further on fuel. Of course, both the Tahoe and Yukon Hybrids have plenty of muscle when it’s needed and can tow up to 6,200 pounds (2WD).

6.0-liter V8, two 60kw electric motors
332 horsepower @ 5100 rpm
367 lb.-ft. of torque @ 4100 rpm
EPA city/highway fuel economy: 21/22 (2WD), 20/20 (4WD)