MOUNTAINAIRE, Ariz. — Heading north out of Sedona, Route 89 runs up Oak Creek Canyon toward Flagstaff until it butts against bluffs of the Mogollon Rim, sheer escarpments stretching for hundreds of miles across Arizona. A ribbon of asphalt threads like a twisted serpent up those cliffs, scaling thousands of vertical feet in a course littered with tricky chicanes and blind hairpin curves.
Drive this road on a Saturday in July, and your progress will be impeded by a slow line of tourists stacking up behind humongous recreational vehicles, with drivers intimidated by their closeness to so many cliffs. Drive it early on an off-season weekday morning, when the tourists have gone home, and you'll be alone to play.
My romp up the cliffs of Oak Creek Canyon turned into an exercise in sure-footed but plush motoring, as I was ensconced in a deluxe edition of the full-size Yukon sport-utility vehicle from GMC.
Dubbed the Denali — a name drawn from native Alaskan Athabascan people to describe "the High One" of Mount McKinley, tallest peak on the continent — this sport-ute represents the top of the Yukon line in a leather-trimmed environment charged with serious horsepower.
The Denali stands out, with sophisticated monochromatic dark color schemes on an exterior form accented by a bold front hood with a rectangular center port grille, flanked by jewellike lenses of sparkling halogen headlamps.
The Denali rides high on special Firestone 16-inch tires and carries front tow hooks and plenty of protective cladding around the lower body, plus side integrated body-color running boards and, at the rear, a functional step bumper that hides a trailer hitch.
The power beneath the hood
Beneath that muscular hood, the Denali conceals a V-8 powerplant that pulses with the strength of 255 horses to charge a hill route like the bluffs of Oak Creek Canyon.
1999 GMC Yukon Denali
An electronic powertrain control module regulates fuel injection, with microadjustments of the mixture of air and fuel. This means instantaneous compensation for stressful effects like altitude, such as my Denali faced in climbing Arizona cliffs, as well as load. The result: continual, dependable power flow.
The iron-block 5.7-liter Vortec engine also provides serious muscle for towing a trailer's load. When coupled at the towing hitch, the Denali can lug a trailer rig weighing up to 6500 pounds.
The Denali’s multi-function console holds a cell phone, loose change, a Starbucks latte, and trendy sunglasses, all at the same time.
This powerplant mates with a four-speed automatic transmission that modulates shift points to enhance torque in lower gears. For ultimate traction, it also packs a four-wheel-drive system that operates with push-button ease.
Essentially, this SUV functions only with rear-wheel traction for typical pavement applications. However, an automatic transfer case — labeled AutoTrac — positions four-wheel-drive mode in standby readiness, thanks to an automatic active transfer case. On-board sensors can detect wheel slippage, and if the road surface should get slick from rain or snow, the system will automatically switch from rear- to four-wheel-drive mode to ensure proper traction.
In addition, you can punch up a low-gear setting of the 4WD mode for venturing off pavement into more rugged terrain, where steady low-end torque helps carry Denali over rocks, logs, bumps and bulges.
A rock-solid foundation
Off-road or on, the Denali feels rock-solid to drive. Its ladder-type chassis uses welded crossbars and a boxed front for increased rigidity in motion.
1999 GMC Yukon Denali
The platform supports a fully independent front suspension and rear semieliptical multileaf spring. Tack on variable-ratio power steering and power brakes tied to the four-wheel anti-lock system, and Denali contains all the important ingredients for smooth maneuvers either on pavement or dirt.
From the driver's vantage behind the wheel, it stands tall and rides high, so you can peer above other vehicles. And the interior, laced with ultimate luxury features, provides plenty of space for riders and gear.
Denali measures up
To find the Denali's position in the GMC lineup of SUV wagons, look somewhere between the compact Jimmy and the full-size, full-length Suburban (which will be renamed Yukon XL next year). The Denali's 117.5-inch wheelbase, 6 inches longer than the two-door Yukon, exceeds the Jimmy's four-door wheelbase by 10 inches yet still falls 14 inches short of the massive Suburban.
Park the Denali next to a Suburban, and you will be pressed to tell them apart, since both exhibit a similar form from front bumper through the B pillar. Beyond the front seat back, however, the Suburban gets enough extra room to add a third tier of seats, so it can carry up to nine people, while the Denali maximizes with five riders because of front bucket seats.
You can detect more subtle differences by comparing the second set of doors on each side. The Suburban's rear door edge forms a straight line from top to bottom and fits in front of the rear wheel well. The door of the Denali has a notch near the bottom to wrap around that arched well. Also, this wagon will fit neatly into a home garage, while a Suburban cannot because of its extra length.
Seat time in the four-door Yukon Denali included a day's drive from Sedona to Las Vegas, following canyon routes, multilane interstate links across Arizona's upper plateau, and one long and straight speed shot through the high desert on old Route 66 from Seligman to Peach Springs.
These tests revealed that the Denali rides smoothly on the open road and