Automakers are spending billions of dollars to get Americans into front-wheel-drive cars, but the manufacturers' success rides on their ability to make a virtue out of necessity.

The need is this: Make a car with lots of room for passengers and luggage. But do it in a way that is fuel-efficient.

Front-wheel drive best meets that joint demand, automakers say. But in their quest for sales, they often are driven to say much more.

Chrysler Corp., for example, touts the "advanced front-wheel-drive technology" in its 1983 Dodge 600ES. Saab says its typical car buyer--an affluent, 38-year-old man--"sees the logic of Saab's front-wheel drive . . . especially after the first snowfall." The Buick Division of General Motors Corp. invites potential buyers to inspect its "elegant, efficient, front-wheel-drive Skyhawk."

The ads are a combination of truth, hype and, at least for the moment, some mild panic.

The truth is that front-wheel drive "is best if you really want a fuel-efficient, space-efficient car," says Stuart M. Frey, Ford's vice president of car engineering. Front-wheel drive reduces car weight and increases passenger and luggage space by placing the drive wheels up front under the engine and transmission. That arrangement does away with the familiar floor hump in the passenger cabin by scrapping the need for a heavy, front-to-rear drive shaft.

"Front-wheel drive is some 50 to 80 pounds lighter than a rear-wheel-drive layout. It gives you package efficiency. But if package efficiency isn't your primary buying motive, there's no fundamental reason why you should want to look at a front-wheel-drive car," Frey said.

Of the nation's three largest automakers, Ford proportionately sells the fewest front-wheel-drive cars. About 36 percent of Ford's 1982 car sales were front-wheel drive compared with about 40 percent for GM and 85 percent for Chrysler. Competitors thus accuse Ford of downplaying the value of front-wheel drive while the company plays catch-up.

But therein lies the hype--and the panic.

The advertisements imply that front-wheel drive is something new. It isn't. The technology has been around both in the United States and abroad since the beginning of the automotive industry. But front-wheel drive wasn't needed in the United States in the days when exterior size, overall vehicle weight and fuel consumption were of little concern to car buyers, automakers say.

The oil crises of the 1970s changed buyer priorities. U.S. automakers at first responded by chopping exterior size and dropping chrome--producing those small, boxy, rear-wheel-drive cars that critics say sacrificed handling and passenger comfort in pursuit of fuel efficiency.

Many Americans didn't like the econoboxes. And after each crisis, they returned to the large, comfortable, greedy rear-wheel-drive cars--often leaving foreign and domestic automakers stuck with bloated small-car inventories. Front-wheel drive offered a compromise--a car for all seasons, with interior space and comfort, good handling and fuel efficiency, automakers say.

But falling gasoline prices still worry some automakers, particularly those with heavy investments in front-wheel-drive programs.

"I've said many times that if gasoline prices dip under $1 a gallon, I would shoot myself," said Chrysler Chairman Lee A. Iacocca, joking with reporters at a recent New York meeting. "What's happening with gasoline prices is a little wacko. It's crazy.

"It took us a billion dollars to get front-wheel-drive fuel economy. But if gasoline is cheap, who needs it?" Iacocca asked.

Chrysler had planned to have 100 percent of its passenger cars front-wheel drive by 1983. But the company still is producing its large, rear-wheel-drive New Yorkers, because the big rides are in great demand during the current fuel glut, Iacocca said.

"We need to slap at least a quarter tax on the gas pump and get prices back up to $1.40 or $1.50 a gallon. We don't want people to get back into dirty habits," Iacocca said. Chrysler has a front-wheel-drive New Yorker ready to roll in the 1984-model year, and the company is investing $6.6 billion in new front-wheel-drive models to be introduced by 1987.

"We planned these cars years ago when we were sure, absolutely sure, that gas prices in the fall of 1982 would be $2 a gallon," Iacocca said.

The terms "small" and "large" no longer mean what they once meant in the domestic auto industry. Most of the domestic cars made nowadays are smaller than their counterparts produced four years ago.

For example, GM uses front-wheel drive in some "large" cars, such as its Cadillac Eldorado. The difference is that those cars, often equipped with 5-liter, V-8 engines, are about 1,000 pounds lighter than like-named models made in 1978. Some people might argue that it is contradictory, in terms of fuel efficiency, to match front-wheel drive with a high-performance engine. But GM and other automotive engineers say the match is compatible, partly because of the overall reduced weight of the cars.

"There is no all-encompassing relationship between smallness and front-wheel drive," a GM spokesman said.

So, then, what about the claims--the excellent handling, the better traction and other boasts of front-wheel-drive superiority over rear-wheel-drive systems?

"It's not a clearly good-and-bad situation. Neither one is perfect," said a GM spokesman, whose company plans to put front-wheel drive in 85 percent of its passenger cars by 1985. Federal officials and consumer organizations agree.

Studies by the National Highway Traffic Safety Administration have yet to turn up any major differences in the safety of driving front-wheel-drive and rear-wheel-drive cars, said NHTSA spokesman Richard Burdette. NHTSA has issued a notice that 320,000 of GM's X-body front-wheel-drive cars made during the 1980-model year may have defective brakes, and may be recalled. But Burdette said the suspected defect, involving brakes that lock during emergency stops, only affects one car line in one company.

The Washington-based Insurance Institute for Highway Safety, auto safety watchdog for the insurance industry, also said that there is little available information on which to compare the handling safety of front-wheel-drive and rear-wheel-drive cars.

The New York-based National Association of Fleet Administrators, which represents both private and commercial car-fleet operators, said in a 1980 report on front-wheel drive that: "Under most conditions, front-wheel-drive cars handle like rear drives." The report added: "But being pulled by front wheels rather than pushed by the rear has its advantages--you get extra traction on slippery roads."

The "extra traction" claim is a staple of front-wheel-drive advertising. But automotive engineers say it isn't all that it's cracked up to be.

Front-wheel-drive traction "degrades when you're moving uphill with a load," especially if the hill is slippery, said Leo Walsh, Chrysler's director of vehicle engineering. It's a simple matter of physics, Walsh said: weight shifts to the rear of bodies moving uphill. Under that circumstance, the traction advantage shifts to rear-wheel drive because the weight is placed over the drive wheels, Walsh said.

On level surfaces, front-wheel drive has the traction advantage because the center of gravity--maximized by the forward location of the drive train--stays over the drive wheels, Walsh said.

"Our first concern with front-wheel drive was to make the most compact car possible for the total market," Walsh said. "We've done that. But we've also brought about much improved handling and directional ability in the process," he said.

Ford's Frey defers to a recent editorial in Automotive News, a major auto industry trade publication, when asked to give his final assessment of the two drive systems:

Said Automotive News: "We hear all too often from the U.S. that if it isn't front-wheel drive, then it isn't the wave of the future. . . . We think that all this is a hoax. The truth is that front-wheel drive and rear-wheel drive have coexisted for many years without any real problems and in all probability will continue to coexist for many decades in the future."