The new transmission is known as 845RE and was designed by German company ZF. It is very similar to the eight-speed automatics in the Audi A8, BMW 5 and 7 Series, and even some Rolls-Royce and BMW models. Chrysler has a license to build the 845RE in Kokomo, Indiana, but for now is importing it from ZF in Germany while the Kokomo factory is readied for assembly of the transmission.

We had the chance to drive a Chrysler 300 and a Dodge Charger equipped with the eight-speed automatic and 3.6-liter V-6 engine. Although we were restricted to the tightly controlled environment of Chrysler's proving grounds, it was clear that the new transmission is better than the current five-speed unit. Under normal acceleration, gear changes happen quickly and so gently as to be almost imperceptibly. Sometimes the only clue that the transmission has upshifted is when the tachometer drops 1000 rpm.

As with most modern automatics, the transmission is programmed to seek high gears as quickly as possible for optimum fuel economy. In eighth gear at 72 mph, Chrysler engineer Tom McCarthy told us the V-6 engine will be turning at just 1100 rpm, providing excellent highway fuel economy. The transmission downshifts promptly when the driver depresses the throttle, dropping one or more gears almost instantly.

In addition to the efficiency gains, Chrysler says the new transmission makes the 300 and Charger quicker. Zero to 60 mph is said to take 7.2 seconds, thanks to the confluence of shorter, closer gear ratios; quicker shifts; and a torque converter that locks up more readily. In fact, McCarthy told us he thinks fewer buyers will opt for cars equipped with V-8 engines, because the V-6 and eight-speed provide brisk acceleration as well as better fuel economy.

For now, the transmission will be available only for the 2012 Chrysler 300, 300 Limited, and 300S; and the 2012 Dodge Charger Rallye, Rallye Plus, and SE. The 2012 model year also marks the return of all-wheel-drive with V-6 engines; it's available for the Chrysler 300S and 300 Limited, and Charger Rallye and Rallye Plus.

Eventually the transmission will be made available on other Chrysler products with the Pentastar V-6. It also should debut on cars equipped with V-8 engines at some point in the future; Chrysler still needs to recalibrate the transmission to work with the V-8s, and also must wait for a steady stream of transmissions before rolling it out across the lineup.

The eight-speed automatic nixes a traditional shift lever in favor of a "shift by wire" paddle. It resembles the throttle control from an airplane and, incidentally, looks remarkably like the shifter found in the Audi A8. Chrysler worked hard to make the shifter fit comfortably in the driver's hand; you simply push the shifter forward or backward and it "clicks" into different transmission positions.

Most models with the transmission will not have a manual-shift mode. Chrysler found that most owners didn't use the manual mode, called AutoStick in the five-speed automatic. Instead, most cars will get a traditional "L" mode that is both more familiar and more useful to most drivers. Only "sporty" models, like the Chrysler 300S and Charger, will receive a manual-shift mode with paddles mounted on the steering wheel.

The 2012 Chrysler 300 and Dodge Charger go on sale later this fall.