If an Isuzu sport utility is on your list of vehicles to consider, you'll find your shopping rather simple for 2005. The Japanese truckmaker is down to just one vehicle in its lineup this year, having dropped the Rodeo and Axiom SUVs at the end of the 2004 model year.

What's left is the Ascender, a very good SUV in its own right, although it's not really an Isuzu.

This is at least the interim replacement for the venerable Trooper, the once popular full-size SUV that was discontinued after 2002, and is based on the Chevrolet TrailBlazer/GMC Envoy models that debuted in 2002.

The Ascender was introduced for 2003 a seven-passenger model only, similar to the extended-length TrailBlazer and Envoy models. But for 2005, a second version has been added - a shorter five-passenger model that is like the regular-length versions of the TrailBlazer and Envoy.

Dealers are hoping that a Thailand-built replacement for the Trooper will arrive in 2006, but Isuzu has not announced a decision yet.

With the end of production last summer of the midsize Rodeo and Axiom at the then-jointly owned Isuzu-Subaru plant in Lafayette, Ind., no Isuzu-built vehicles are being made for the U.S. market this year. Both models of the Ascender are built by GM along with the TrailBlazer and Envoy at a plant in Kansas City.

The Ascender is a near clone of the TrailBlazer and Envoy, which also are the basis for the Buick Rainier and now-discontinued Oldsmobile Bravada, as well as the soon-to-be introduced Saab 9-7X.

Even though it is based on the TrailBlazer and Envoy and built by GM, the body of the Ascender looks more like an Isuzu product than something from GM. It doesn't ride and handle differently, of course, because it's essentially the same vehicle underneath. But the ride and handling of these outstanding GM midsize SUVs are among their greatest attributes.

They're not quite as carlike as the current generation of the Ford Explorer, because the Explorer has four-wheel independent suspension and the Ascender/TrailBlazer/Envoy still have a solid rear axle, but they nevertheless have many carlike attributes, including very comfortable and accommodating interior packages.

And they are alone among the truck-based SUV class in gaining a U.S. government four-star rating in rollover testing, the best any sport utility has achieved.

The longer Ascender (base price $28,569 for two-wheel drive and $31,398 for four-wheel drive, plus $685 freight), which we tested for this report, is nearly as roomy as a full-size SUV, which puts it up next to vehicles such as the Ford Expedition and Toyota Sequoia.

Adding the five-passenger model, $25,959 for two-wheel drive and $27,959 for four-wheel drive (plus freight), gives an option to consumers who don't need the extra length and the third row of seating. GM last year added a version of this five-passenger model to the Buick lineup as well, the above-mentioned Rainier.

In a reverse of the way the TrailBlazer and Envoy were introduced - the short version first, then the longer model a year later - Isuzu chose to go with the bigger one first.

Perhaps that was because the brand had never had an SUV with room for more than five passengers, and when the Ascender was introduced in 2003, Isuzu still had the five-passenger Rodeo and Axiom models in its lineup. Recent trends in the SUV market show that buyers prefer three rows of seating.

With the extended model, the third seat is standard. Outfitted with front bucket seats and the two rows of split-folding rear seats, the Ascender can carry up to seven people fairly comfortably, although as with most vehicles with a third row of seating, it's best left to the kids to crawl back there and put up with slightly limited legroom.

If the third seat isn't needed for passengers, it can be folded flat into the floor, creating a massive rear cargo area while maintaining seating for up to five.

Under the hood of both versions is the same 4.2-liter inline six-cylinder engine used in the Envoy and TrailBlazer, rated at 275 horsepower and 275 foot-pounds of torque. It is connected to a four-speed automatic transmission.

A 5.3-liter V-8 engine is optional in the longer model of the Ascender - the same V-8 offered in the TrailBlazer and Envoy extended-length models, rated at 290 horsepower and 325 foot-pounds of torque.

The V-8 was included in our test model, offering the kind of pep and trailer-towing torque expected of larger SUVs such as this, especially here in Texas. Either engine gets a four-speed automatic transmission.

The interior of the Ascender is quite carlike, with the amenities of a premium sedan. Some of the amenities include usable cupholders front and rear, dual-zone climate control, programmable power windows and door locks with remote, tilt steering column, cruise control, dome/cargo/reading lamps, extra 12-volt power outlets in the center console/second seat area/cargo area, and rather plush cut-pile carpeting throughout. Among other standard features are five-link coil-spring rear suspension, stainless-steel exhaust, power rack-and-pinion steering, four-wheel antilock disc brakes, fog lights, rear wiper/washer, six-speaker AM/FM/compact-disc stereo with clock, privacy glass, woodgrain door trim, and a universal garage/gate opener.

Outside, there is a heavy duty trailer hitch, as well as a full-size spare tire. Standard trailer capacity is 5,700 pounds for the extended-length model.

One of the Trooper's greatest attributes was its off-road agility, and the Ascender follows that same pattern. Unlike a lot of the carlike SUVs on the market today, the Ascender has the traditional body-on-steel-ladder-frame arrangement of a truck, to make it sturdier and more rugged.

To help in serious climbing and descents in off-road situations, there is low-range gearing via a transfer case, like there was in the Trooper.

The four-wheel drive system, also included on our vehicle, is GM's Autotrac, which has three driver-selectable modes - rear-wheel drive, part-time four-wheel drive, or full-time automatic four-wheel drive, which shifts power to the front wheels as necessary to maintain traction (with no input from the driver).

You can leave it in full-time four-wheel drive and never worry about it; when the onboard computer detects slippage with the rear drive wheels, it puts power to the front. There is a rotating switch on the dash to the right of the steering column to allow the driver to select the desired mode.

We did some limited off-road driving - nothing severe - and found the Ascender to be quite agile off the pavement, through mostly dry washes and up some moderate hills. Our test vehicle, with the Adriatic blue exterior color and a gray interior, was the fully loaded Limited four-wheel-drive model, which topped out at a pricey $39,468 (including freight).

Among the extra-cost items were the V-8 engine ($1,499); the "LS four-wheel-drive equipment package" ($3,267), which added a six-disc in-dash CD player, steering wheel audio controls, rear audio controls with earphone jacks, leather-wrapped steering wheel, a driver-information center, automatic climate control, rearview mirror with compass, power moon roof, limited-slip differential, 17-inch alloy wheels, and roof-rail crossbars. The Limited package $3,591) included leather interior, heated front seats, power front bucket seats with memory driver's seat, memory mirrors with turn-signal indicators, Bose premium audio, OnStar, adjustable floor pedals, rain-sensing wipers, power quarter windows, running boards, and a 3.73 axle with 6,200-pound towing capacity. Also included were roof air bags ($499) and underbody shields ($199); a package discount of $1,670 was applied to the total.

The Ascender comes with a three-year/50,000-mile basic bumper-to-bumper warranty, a seven-year/75,000-mile powertrain warranty, and a six-year/100,000-mile anti-corrosion warranty. Free roadside assistance is included for the duration of the powertrain warranty.

EPA fuel economy ratings are about average for this class of SUV: 15 miles per gallon in the city and 20 mpg on the highway for the inline six-cylinder model, and 14 city/19 highway for our V-8 test model. The tank holds 25 gallons of fuel, and unleaded regular is suitable.

G. Chambers Williams III is staff automotive columnist for the San Antonio Express-News and former transportation writer for the Star-Telegram. His automotive columns have appeared regularly in the Star-Telegram since 1995. Contact him at (210) 250-3236; chambers@star-telegram.com.

2005 Isuzu Ascender 7-passenger The package: Midsize, four-door, seven-passenger, rear- or four-wheel-drive, inline six-cylinder or V-8 powered sport-utility vehicle. Highlights: Isuzu borrowed this SUV from partner General Motors to replace the Trooper. It is the same as the Chevrolet TrailBlazer EXT and GMC Envoy XL, but with slightly different exterior styling and Isuzu badging. Negatives: Can get pricey with all the options. Engines: 4.2-liter inline six; 5.3-liter V-8 Transmission: 4-speed automstic. Power/torque: 275 hp./275 foot-pounds (six cylinder); 290 hp./325 foot-pounds (V-8). Length: 207.8 inches. Curb weight: 4,790-5,020 pounds. Trailer-towing capacity: 5,700 pounds (6,200 with optional 3.73 axle). Brakes, front/rear: Disc/disc, antilock. EPA fuel economy: 15 miles per gallon city/20 highway (six); 14 city/19 highway (V-8). Fuel capacity/type: 25 gallons/regular unleaded. Major competitors: Ford Explorer/Mercury Mountaineer, Toyota 4Runner, Mitsubishi Montero, Dodge Durango, Acura MDX, Nissan Pathfinder, Chevrolet TrailBlazer EXT/GMC Envoy XL. Base price: $28,569 plus $685 freight (six-cylinder, two-wheel drive). Price as tested: $39,468, including freight (Limited V-8, four-wheel drive, with options). On the Road rating: ***** (five stars out of a possible five). Prices shown are manufacturer's suggested retail; actual selling price may vary.