If the United Nations ever had to choose an official vehicle for chauffeuring its dignitaries around, it might well be the Navajo, Mazda's new sport utility vehicle.

The 1991 Navajo shows what a melting pot the light truck industry has become. It is really a rebadged version of Ford's new Explorer, which is designed and built in the United States. But it has an engine made in Germany and is sold by a Japanese carmaker - after being branded with an American Indian name.The four-wheel-drive Navajo also marks Mazda's first foray off the road and into the tangled brush of the sport utility market, which has attracted an unprecedented number of would-be carbuyers in recent years.

Both the Navajo and Explorer roll off Ford's Louisville, Ky., assembly line with identical bodies, interiors and underpinnings. They are distinguished only by different nameplates and grillework.

The Navajo comes in a two-door version only, while the Explorer comes in a four-door model as well, where much of the gain in the "passenger truck" market has been.

Mazda insists it decided against a four-door Navajo because it "would not be in keeping with the company's image as a sporty division." It also says such a vehicle might steal sales from its MPV minivan, which is offered with all-wheel-drive as an option.

The Mazda Navajo has a wide range of features included in its $17,835 base price: AM-FM stereo, power windows, mirrors and door locks and anti-lock drum brakes in the rear. Also standard is a transfer case that allows one to engage four-wheel-drive with a touch of a button.

Two extra-cost "option groups" are offered, although some items can be ordered separately. The "Premium" package ($1,225) adds air conditioning, glass sun roof, speed control and larger all-terrain tires. The "Leather" package ($3,110) includes all those items plus leather seats, a 4-speed automatic transmission, roof rack and a towing package.

Driven for this review was a Navajo fitted with the second package, plus an "LX" trim package that added $350. It cost $21,750 as tested, including a $455 destination fee.

A similarly equipped Ford Explorer was estimated by Ford to cost $22,406.

As mentioned, the Navajo is a virtual clone of the Explorer both inside and out. That is by no means bad, since the Explorer is considered to be at the head of its class in many categories.

Its 4.0 liter V6 engine, for instance, is capable under all conditions and delivers ample acceleration despite the Navajo's 3,886-pound weight. It is essentially a bored-out version of Ford's 2.9 liter V6, with horsepower raised to 155 at 4,200 rpm and torque increased to 220 foot-pounds at 2,400 rpm.

Fuel economy with the standard 5-speed gearbox is only 15 city/20 mpg highway; 16/20 with the automatic. This alone means buyers should seriously evaluate their needs for such a vehicle.

Its dashboard houses a complete array of legible analog gauges. All controls are sensibly arranged except for the Ford-designed wiper stalk, which has the "off" position between the delay settings and normal speeds.

There is ample head and leg room throughout, and all seats are comfortable yet supportive. The rear seats fold forward independently, increasing cargo space to nearly 70 cubic feet.

The Navajo's 102.1-inch wheelbase gives it a well insulated and stable highway ride, but it is not nearly as smooth as a four-door Explorer evaluated last year, which has a 10-inch longer wheelbase.