Although Chrysler did much pioneering, there were times it appeared to allow other manufacturers to test the waters. For example, other manufacturers have been offering four-speed automatic overdrive transmissions for a number of years now. But Chrysler seemed content to update and fine-tune its excellent TorqueFlite three-speed automatic - a transmission, by the way, which was much copied. Now for '89 in its New Yorker line, it introduces the auto industry's first fully adaptive, electronically controlled four-speed automatic transaxle. Known as ''Ultradrive,'' Chrysler claims it is the result of four years of research and development. Well, the company must have done something, since more than 50 U.S. patents have been filed to protect the technology. In essence, the new Ultradrive automatic, according to Chrysler, provides faster, quieter and smoother response, improved shift quality over the life of the transmission, and improved fuel mileage. One drive in the test car (a New Yorker Landau from Scott Chrysler-Plymouth, 2120 33rd St., Allentown), though, was all that was needed to realize the transmission certainly knew what it was doing. How it does this, obviously, is rather complicated and a full explanation, no doubt, would put most readers to sleep. Let's just say that among the major features setting it apart from other transmissions are its fully adaptive electronic controls, the world's first application of this technology in mass production. It is also the only electronically shifted automatic built in the United States. The transmission, however, shouldn't overshadow the New Yorker, Chrysler's flagship and a nameplate that marks its 50th anniversary. For those interested in ancient history, the New Yorker was introduced in 1939 and was the ''official'' car of the New York World's Fair of that year. Hence the name. (Before some sharp auto buff tells me there was a Chrysler New York Special in 1938, I'll say it now.) For a nameplate to be around for 50 years (it is the oldest continuing model nameplate in the world) there has to be something appealing about it for consumers. This year's model offers sophistication, luxury, world-class engineering; all at a competitive price. It also offers one of the outstanding new-car warranties in the world; certainly not a small point. For basics, the New Yorker is a front-wheel drive six-passenger four-door sedan in the mode of contemporary large cars: that is, smaller on the outside but roomy on the inside. It has a wheelbase of 104.3 inches, length of 193.6 inches, width of 68.5 inches, height of 53.5 inches and curb weight of 3,276 pounds. If there were just one thing to do to this car to make it even more competitive, it would be just to make it a little wider. Say about two inches. As it is, though, one really can't complain. Styling is crisp and clean and somewhat formal. No big surprise s, no big breakthroughs. One of the most interesting points of its design is the rectangular waterfall grille, which not only grabs the eye, but accents the concealed headlamps, minimal frontal area, sloped hood and raked windshield. At the other end, the rear window is almost vertical and the trunk deck sits high. The interior of the test car with its Mark Cross leather upholstery was as luxurious as any other production car. Seating is comfortable, appointments numerous and the electronics dazzling. A new feature this year (the present New Yorker was introduced for the 1988 model year) is an electronic memory driver's seat which allows for two people who drive the car most frequently to program and set seat and recliner positions that can be recalled by pressing a button. There is also a new anti-theft system (monitoring doors, hood, trunk and ignition) that is armed by simply locking the vehicle with one of the power front door locks, not the key. Whe armed, the system responds to unauthorized entry or ignition tampering by flashing the tail and park lights, sounding the horn and disabling the engine ignition system. In a separate innovation, the power door-lock system prevents the driver's side door from being locked with the door switch while the key is in the ignition. This may not make the car go any better but it certainly is one of the most practical items I have come across in quite awhile. Perhaps it shouldn't come as a surprise but the New Yorker is not a very difficult car to drive. Everything is power, and even though it is a large car by today's standards, it really isn't large (on the outside) and is easy to maneuver and park. The suspension, featuring gas-charged struts and anti-sway bar up front and automatic load leveling and height control in the rear, is tuned for the smooth, quiet ride befitting any luxury car. Another interesting feature on the test car was the antilock brake system (ABS). This system, as I have belabored many times in the past, is one of the greatest safety features ever invented and can substantially improve a car's stability during braking by preventing brakes from locking. ABS does not usually come into play except in emergency situations, but when it does, a driver will be glad to have it. The New Yorker is powered by a three-liter/181-cubic-inch V-6 featuring overhead cam and multi-point fuel-injection. This engine was developed jointly by Chrysler and Mitsubishi and is a dandy one at that. Rated at 141 horsepower at 5,000 rpm and 171 foot pounds torque, the engine, together with the four- speed automatic transmission, provides plenty of power. The four-speed allows for lower gearing at the bottom end and higher gearing at the top, which really is the way to go. I'm sure no one will have any complaints about performance. And it is doubtful if anyone will complain about fuel mileage. The test car, using unleaded regular, averaged 15 miles per gallon for city driving and 25 mpg over the highway. Base price for the New Yorker Landau is $19,509 and standard equipment includes all items expected in a luxury car. In other words, you wouldn't be ashamed to drive it even without any options. However, when buying a luxury car, many people want to go all the way. Adding even more to the test car was the Mark Cross Discount Package at $2,467 (after a $200 discount). The other options were: upscale radio, $482; four-wheel disk ABS, $926, and power sunroof, $776. Add $585 for delivery and the final price came to $24,665, certainly a good sum of money but quite reasonable for the market niche. The New Yorker's warranty is known as the ''Crystal Key Owner Care Program.'' It still carries the company's 7-year/70,000-mile powertrain warranty and 7-year/100,000-mile protection against outer-body rust-through, but adds a 50,000-mile/5-year basic warranty - an owner takes ca re of normal maintenance, adjustments and wear items, Chrysler takes care of everything else (and with no deduction), and a 24-hour toll-free hotline. Now you know why Lee Iacocca looks so smug when he talks about this car.