SOMEWHERE amidst the rocks and snow of the Shenandoah Valley, Gerry became a believer. Gerry the Toyota Man, Mr. Anything-but-an-American-Ride Gerry, the dude who once bought a dinky Volkswagen pickup when he couldn't get the Japanese model he wanted, that Gerry fell in love with a Made-in-Indiana, We-Be-American, 1992 GMC Sierra 4x4 truck!

Gerry's one of those brothers who always runs his mouth about how Americans in general and General Motors in particular can't make anything right. He can quote chapter and verse of Consumer Reports and can recite a litany of automotive woes from everyone he knows who has ever owned an American car or truck, and he swears that he knows legions of mechanics who won't go near anything with a GM nameplate.

For years, I've been telling Gerry that he's full of it -- largely because I drive lots of vehicles from lots of manufacturers, and know for a fact that no company, foreign or domestic, makes stuff as bad as its critics claim, nor as good as its advertisements proclaim.

So I invited Gerry to zip up his lips and take a trip with me out to the Shenandoah Valley, where we found some snow-covered, rock-strewn paths for a bit of off-roading in the Sierra 4x4. We bounced around for a couple of hours, hit what we assumed to be several ditches, sideswiped a few fallen tree limbs and generally had a good time.

Gerry didn't say much. But what he did say was interesting: "{Expletive}, man! I could buy one of these."

Background: GM rolled out its first full-size pickup in 1917. It has long been a leader in that market segment, although it sometimes has had to suck the dust of Ford Motor Co., maker of the famed F-series pickups. Chrysler Corp., too, has done well with full-size trucks. Heck, trucks have helped to keep Chrysler rolling when seemingly everything else was going wrong at the company.

Full-size pickups, in fact, are where the Big Three still hold some supremacy over their Japanese rivals. But that position won't go unchallenged much longer. Toyota, despite corporate disclaimers, is working hard to introduce full-size trucks in the U.S. market. And if Toyota makes that move, others will follow.

But here's betting that any Japanese foray into the full-size pickup market will not be as successful as Japan's move into car sales -- not as long as GM continues turning out trucks as good as the Sierra 4x4.

Complaints: At night, the illuminated instrument panel creates a disturbing glare on the rear window. But regular truck drivers call that a wimp's complaint. Wimp or not, I don't like it. Also, it makes little sense to me to do a super-duper job painting a truck bed that's going to get scratched up, dented and abused by all of the things that work trucks, like the Sierra 4x4, carry. A bedliner ought to be made standard on these things.

Praise: Totally solid construction. Not even Gerry could find a fit-and-finish flaw. Terrific o ff-road manners, thanks to the optional Z-71 off-road package, which includes heavy-duty springs and shocks. Excellent legroom, headroom and on-road driving manners. Easy-to-use four-wheel-drive transfer case.

Head-turning quotient: The Sierra proves that pretty does not necessarily mean dainty.

Ride, acceleration and handling: Superior acceleration. No wonder: The test Sierra 4x4 was equipped with an optional 5.7-liter V-8, electronically fuel-injected engine rated 210 horsepower at 4,000 rpm. A total beast! The standard engine is a 4.3-liter V-6 rated 160 horsepower at 4,000 rpm, which is not exactly tame. Braking (power-assisted front discs and rear drums) is excellent. Rear anti-locks are standard.

The tested Sierra 4x4 can carry up to 1,884 pounds and pull a trailer load of 7,500 pounds.

Sound system: Four-speaker AM/FM stereo radio and cassette by GM/Delco. Excellent.

Mileage: About 16 miles per gallon (34-gallon tank, about 530-mile rang on usable volume of 87-octane unleaded), combined city, highway and off-road, two occupants and light cargo.

Price: Base price is $15,583. Dealer's invoice price is $13,526. Price as tested is $21,529, including $5,351 in options and a $595 destination charge.

Purse-strings note: The Sierra 4x4 is a darned good truck even without the options. Save money. Scrap 'em. Compare with Ford F-150 and Dodge Ram 150.