When it comes to trucks, numbers matter, arguably more than they do with cars. The most popular engine for the
GMC Yukon is the 5.3-liter V8, which produces 320 horsepower and 340 pound-feet of torque. Our test Yukon was listed at 5677 pounds.
Examining these numbers should give a good idea of how a 5.3-liter Yukon will perform against the competition. By comparison, the 2008 Ford Expedition puts up a 5.4-liter V8 making 300 hp and 365 lb.-ft. of torque with a six-speed automatic and tips the scales at 5805 pounds. The 2008 NissanArmada's 5.6-liter V8 makes 317 hp and 385 lb.-ft. of torque, mates to a five-speed automatic and carries a curb weight of 5593 pounds. Toyota's redesigned 2008 Sequoia is offered with a 5.7-liter V8 making 381 hp and 401 lb.-ft. of torque with a six-speed automatic and weighs 5730 pounds.
Note, however, that the Yukon's 5.3-liter engine comes with a four-speed automatic transmission, while many full-size SUVs now come with five-, six-, and seven-speed automatics. More gears generally means smoother operation, better fuel economy, quicker acceleration performance or all three. The Yukon's four-speed automatic negates any power advantage the Yukon might otherwise have enjoyed at least as far as outright acceleration is concerned. Put another way, while it'll easily hold its own on the interstates, the Yukon isn't going to win many stoplight races.
Not so, though, the Yukon Denali, which would leave its lesser sibling and most of the others in the dust were its driver so inclined. The Denali packs a 380-hp 6.2-liter V8 and six-speed automatic. It delivers willing power at any speed and makes the Denali feel like a much lighter vehicle.
Fuel economy is a much better story for the Yukon. EPA fuel economy numbers range from 14 mpg city and 19 highway for the 4.8 2WD and 5.3 4WD models to 14/20 for the 5.3 2WD to 12/18 for the AWD Denali with the 6.2 V8. The Yukon's Active Fuel Management system, which shuts down half of the engine's cylinders under light load helps the 2008 Yukon best the Expedition and Armada and run neck and neck with the new Sequoia.
In towing, the Yukon's 8200-pound rating trails all the competitors. Ford and Nissan rate their entries at a maximum of 9100 pounds, and the new Sequoia can tow up to 10,000 pounds. On the other hand, GM tends to be more conservative than other manufacturers with its tow ratings. Tow ratings have almost as much to do with lawyers and marketing professionals as they have to do with engineers.
Driving a Yukon is pleasant. Power comes on smoothly, with no surges or hiccups, and it is accompanied by a pleasant tone that reminds us of classic dual exhaust. Transitions effected by the fuel-management system are invisible, with the only indication a telltale in the information display in the tachometer. The four-speed automatic selects gears with little fanfare. The six-speed automatic in the Yukon Denali is even smoother; it also has a manual shift function managed by a rocker switch in the handgrip on the column shift lever.
We found the new two-mode hybrid system worked seamlessly. The system uses two electric motors in GM's new Electrically Variable Transmission (EVT) that has four fixed gears. The EVT is mated to a 6.0-liter version of the 6.2-liter V8 that also has Active Fuel Management. Total output is 332 horsepower and 367 pound-feet of torque. One of the motors aids power at low speeds and the other lends a hand at highway speeds. With just a little throttle, the electric motor can propel the Yukon up to 30 mph. Get on it a little harder, and the gasoline engine kicks in just as smoothly as in any Toyota hybrid. Like other systems, the gasoline engine turns off at stoplights and restarts as soon as it's needed.
The better news is Hybrid fuel economy. With 2WD, the Yukon Hybrid is rated at 21 mpg in the city and 22 on the highway. With 4WD, those numbers are 20 city/20 highway. The 2WD city number matches that of the four-cylinder Toyota Camry, though the highway number is substantially less than the Camry's 31 mpg. While the Hybrid has considerably less towing capacity at 6000 pounds with 4WD and 6200 pounds with 2WD, that's still enough for the Hybrid to be used for many towing needs.
Driving Yukon models along twisty, two-lane roads in Georgia and on coastal California roads, we found they tracked flat and smooth through 70-mph sweepers marked with 40-mph advisories. Steering response in GM's big SUVs has been criticized in recent years. Like all large SUVs, it is still somewhat slow, but it is more precise, thanks to the rack-and-pinion steering that made its debut in the Yukon when it was redesigned for the 2007 model year. The handling is also sharper than in the previous generation, due to a stronger and stiffer frame; coil-over-shock independent front suspension; revised, multi-link, live axle rear suspension; and a wider track, by some three inches in front and an inch in the rear. Still, the Yukon is a full-size truck and is prone to body lean in turns and slow reactions in quick changes of direction.
We found the ride to be comfortable and controlled on South Carolina freeways, some of which were glass-smooth while others were buckled from severe winters. With the Denali's available 20-inch wheels, the suspension didn't jolt, even on Chicago's notoriously pockmarked streets. The turning circle impressed us. It takes less space to make a U-turn in a Yukon than it does in other SUVs in this class; even some relatively small vehicles such as the Mitsubishi Eclipse need more space to turn around than the Yukon. This is helpful in a world of big SUVs and compact parking spaces. The brake pedal was solid and firm, with a prompt and confident response.
Abundant sound deadening material mutes road noise, but wind whistle easily leaks around the multiple door seals. That the stereo has to be on for the navigation system to operate is irritating, a strategy shared with expensive Mercedes vehicles. We like that GM vehicles now provide off switches for the daytime running lights and for the inside rearview mirror's auto-dim function. next page