New exterior badges that read "GMC" in ruby red replace the "GMC Truck" logo.

GMC is in the process of launching the 1999 Denali, a luxurious step up from the Yukon that comes with styling cues designed to set it apart from Chevy's Tahoe. The Denali is part of GMC's plan to move more upscale.

The Denali takes those looks a step further. It's distinguished by a body-colored front bumper that emphasizes the big grille, giving the Denali a powerful look. Body-colored cladding complements integrated body-colored running boards. The horizontal lower body contour flows to the rear where a functional step bumper cleverly shrouds a standard trailer hitch. Body-colored door handles, mirrors and luggage rack complete the Denali's monotone look. Chromed aluminum 16-inch wheels further distinguish it from the Yukon.

The Denali comes in one trim level and retails for $43,495.

All Yukons, including the new Denali, are fitted with GM's 5.7-liter Vortec V8 engine. It's a smooth, powerful and efficient engine, enabling the Yukon to accelerate quickly and pull trailers up to 7000 pounds.

A redesigned case for the automatic transmission reduces vibration and noise in 1998 Yukons. New software improves the efficiency of the electronically controlled four-speed automatic by adjusting line pressures according to operating parameters. A deeper transmission oil pan improves transmission durability and fluid life.

Two trim levels, SLE and SLT, are available for the Yukon. Two-wheel-drive Yukons starts at $30,244, while 4WD models start at $33,244.

A new luxury convenience package is available on SLT models with front bucket seats that includes: a 3-channel Homelink transmitter for opening garage doors and turning on lights, a touring suspension with specially tuned and Bilstein shocks, heated driver and front passenger seats, heated electrochromic outside rearview mirrors, and a six-way power front passenger seat.

These full-size trucks cost $4,000-$8,000 more than compact sport-utilities such as the GMC Jimmy and Ford Explorer, but provide a lot of utility and value when compared with the much more expensive Toyota Land Cruiser and Range Rover.

Once inside, the Yukon offers a pleasant cabin. The high-back bucket seats are comfortable with inboard armrests. Like other big sport-utilities, the Yukon offers a commanding view of the traffic, while the long side windows provide good visibility over the shoulder.

The instrument panel is straightforward and the dash is an attractive design with rounded curves. Storage space abounds in the form of a glovebox, center console, door pockets and nets behind the seats. Well-designed cupholders are everywhere, while extra power outlets for cellular phones and radar detectors make life easier.

People in the back seats aren't forgotten. The back of the console provides them with cupholders and storage. Map lights are available and the heating and air conditioning is directed to keep them comfortable.

A rear air conditioning unit with overhead controls gives the people in back some choices. Standard on SLT trim, the system uses two main and two window-shade-type outlets located in the headliner above the rear seat. Control knobs positioned in the rear seats allow blower speed adjustments.

With the rear seats folded down, the four-door Yukon offers 118.2 cubic feet--nearly identical to the Expedition--while the Suburban provides 149.5 cubic feet. Buyers may order these vehicles with either the split panel doors or a tailgate. Tailgates are best for most folks as rearward visibility is much better and they work well for loading groceries. Split panel doors may be more utilitarian for serious duty as they eliminate the lowered rear lift gate.

A new Autotrac active transfer case designed to enhance traction and driver control comes standard on four-wheel-drive Yukons. Controlled by an electronic transfer case, the system includes the traditional modes of two-wheel drive, four-wheel drive, and low-range four-wheel-drive. Pressing the Auto 4WD button puts the vehicle in an on-demand four-wheel-drive mode. When a condition requires four-wheel drive, sensors detect wheel slippage and apportion greater amounts of torque to the front wheels until the rear wheels regain traction. The transfer case can be left in Auto 4WD on all surfaces without damage or wear occurring. If continuous rear-wheel slippage occurs for a sustained time, the system will automatically go into 4 Hi mode to protect the actuator motor.

An optional locking rear differential is extra insurance against getting stuck a long way from home.

We recommend ordering the optional trailer-towing equipment, which includes a Class III receiver. It will enhance the value of your Tahoe even if you don't plan to do any towing. In our experience, the Yukon and Tahoe make stable, powerful tow vehicles with good brakes.

GM's OnStar Communication System makes traveling in a Yukon safer and more secure. A dealer-installed option, OnStar integrates on-board advanced vehicle electronics with Global Positioning Satellite technology and a hands-free, voice-activated cellular telephone, linking both the driver and the vehicle with the OnStar Center. OnStar services include emergency services, theft detection notification, stolen vehicle tracking, remote door unlock, roadside assistance with location, and route advice. A new database has been developed with more than 3.2 million listings of restaurants, hotels, gas stations and entertainment spots. OnStar automatically alerts the communications center when an airbag has been deployed; they immediately call the driver to determine whether help is necessary.

The Yukon does a good job of cushioning bumps, though it floats a bit too much for our taste. The current generation of GM trucks suffer from mushy brake pedals and the Yukon is no exception. They stop well, but quick response calls for firm, positive pedal pressure. The Yukon seems to offer better braking performance on dirt roads than the Expedition.

A 4WD Yukon is a highly capable--if somewhat bulky--off-road vehicle. It handles well on rough roads and the 4WD system helps it through slippery conditions.

We drove the Yukon over silty two-tracks, muddy trails and roads covered with snow and ice in Michigan's Upper Peninsula and it never hesitated. A Yukon will go anywhere the most serious of outdoorsmen are likely to go.

Those who need even more cargo capacity should shop for a Suburban or hold a yard sale. These trucks are stable, comfortable cruisers that easily slice through nature's worst.