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In the 1950s and 1960s, as American automakers were busily honing the art of the automatic transmission, European automakers tried to stretch manual transmission technology as far as possible in an attempt to offer the user-friendliness of automatic with a semblance of the economy and performance of a stickshift. The semiautomatic transmission was born.

First, let's consider the case for semiautomatic transmissions. I, along with some American Everythingians, tend to forget that as a rule most European and Japanese cars are of smaller engine displacement than typical American fare. These smaller engined cars are intended for the home market and countries where fuel economy is important and taxation by displacement is practiced. The cars are frequently fitted with larger engines for export, and frequently only the US market gets the truly large engine options as standard equipment. The United States, with plentiful fountains of gasoline, can allow for big engines with energy inefficient transaxles as well as full-time, 60/40 split four wheel drive systems. In my opinion, the low maintenance cost of driving in the US as well as reasonable leasing have caused the sport utility vehicle boomlet here. But that's a metanode in itself.

Semiautomatics are conceptually simple. Instead of depressing a clutch, the driver either pulls in on a column shift or pushes down on a floor mounted lever. Continuing to place pressure on the lever the driver selects a gear, setting off without having to first find the moment of resistance, the friction/bite point after which the car begins forward momentum. Some cars (notably the Volkswagen Beetle) allow the driver to continue accelerating through a shift; other systems still require the driver to momentarily disengage the throttle while selecting gears. The pressure placed on the gear lever trips a switch, engaging a hydraulic clutch actuator (foot replacement) that is released only after movement has been obtained. In this way the system avoids use of a torque converter as found on an automatic transaxle. The fully hydraulic nature of impellers and turbines in a torque converter provide for competent starts and shifts with little or no shudder, but with the price of the added fuel consumption of keeping the flywheel rotating. Semiautomatic transmissions combine mechanical and hydraulic aspects to preserve some economy while attempting to provide fluid movement.

To stop the car, the driver avoids the need to depress a clutch or typically touch the gear selector. He/she need only apply the brake, moving the selector into neutral as the car winds to lower revolutions. In every action the gear selection movements in manual and semiautomatic cars are identical, save clutch actuation. Riding the clutch is possible only at a stoplight, if one depresses the brake and holds 1st/low gear. Many modern semiautomatics (Saab Sensonic) will emit a warning beep if the car is left in low gear for more than 30 seconds, requiring tolerance of incessant beeping in exchange for a quick getaway.

Towards the end of the 1950s certain European models began to sport semiautomatics, though they were installed as afterthoughts and not well integrated with platform design. Saab and Volkswagen were notable early adopters, with Volvo and I believe Rover experimenting with semiautomatic systems before offering fully automatic models with primitive planetary gear setup, two or three forward gears lashed to power-spilling torque converters. My experiences with Volvos tell me that the semiautomatic option was not popular with their 1960s era models, possibly due to maintenance issues or the performance/economy hit inherent with the clutchless design.

Nowadays semiautomatic setups have made a comeback, but with a twist. Some models, such as cars produced by Renault, Saab, and Mercedes-Benz, notably the Benz A-Class and Swatch models, sport electronic semiauto versions that require gear shifting at all times. Now popular in the United States are manumatic transmissions, fully automatic transmissions with electronic "shifting" of gears via a up/down shift gate. Manumatic drivers aren't really choosing gears; rather they're ordering the automatic tranny's "brain" to interrupt its preprogrammed cycle and do the master's bidding. In my few test drives with manumatics the car does what it wants anyway, obeying sometimes but frequently overriding driver input with what it thinks might be a more cautious move (shifting above 4000 rpm seems to be real risky for most car computers). Many manumatics refuse to go to redline; many also drop the car to low gear at a full stop. All told, it's still an attractive option for those who prefer auto but want to push the car a bit sometimes, but not make stupid mistakes like testing the strength of the tachometer needle.

Semiautomatics are now available in a new form. They are derived from F1 transmissions, so they use paddled attached to the steering column to shift the gears. The transmissions are normal manual transmissions that have computer controlled hydraulics to up- or down-shift when the driver hits the appropriate paddle. The computer also automatically blips the throttle on down-shifts, and can be put in a fully automatic mode, although it's no where near as smooth as a torque converter style automatic.

The purpose of these transmissions is easy shifting, with two advantages over traditional automatics. They don't suck power with slippage in a torque converter, and they don't affect fuel efficiency, which is a big draw in Europe.

Only three cars in my knowledge in the U.S. have had these new types of semiautomatics; the Ferrari 355 and 360 series, and the BMW M3. In Europe, new Fiats and the Toyota MR2 also utilize F1-derived transmissions, and many more are to follow because of gas prices and fuel-efficiency taxes.

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