Q:I keep reading and hearing more about dual-clutch transmissions. What exactly are these things, why would I want one on my car and will these become more common? - Jeremiah C., Excelsior.
A: Basically, it's a very efficient and responsive shiftable automatic transmission - that is, a transmission that can do the shifting on its own, or that you can shift, e.g., with paddles or buttons or by moving the shift lever up or back to upshift or downshift. Dual clutch is a better name for it, though, because a conventional automatic transmission uses a fluid-filled torque converter and therefore has a fluid coupling between engine and transmission. A dual-clutch transmission engages mechanically with clutches and is crisper. Dual clutch transmissions (DCTs) also engage faster than a typical manual transmission, which has a clutch the driver operates with a pedal to shift gears or place the transmission in neutral to idle or park. A DCT's two clutches work with alternating gears, which allows the automatic mode and the quickness.
In my opinion - the builders of these transmissions disagree, or they wouldn't incur the cost - people tend to prefer either manual or automatic transmissions. The manual drivers enjoy shifting and having that extra degree of control over the vehicle, or participation in controlling it, while automatic drivers view shifting as a nuisance.
The people I know whose vehicles have shiftable automatics, seldom use the manual shift mode. They're not hardcore "manual" people so they don't bother to shift manually even though they can do so without a clutch pedal; in other words, it's not the clutch pedal, per se, they dislike about shifting - they just don't want to bother with it.
Where dual-clutch technology shines is in competition because it's so fast and crisp. The process is very smooth and efficient; it's also a strong technology, capable of handling racing engines. This transmission design will become more common, encroaching on both the conventional manual and automatic markets. Auto Week recently said that Volkswagen was moving to replace all of its automatics with DCTs. Whether you would want one depends on how much you like to shift. If you're a habitual manual transmission guy or gal, you may find it more satisfying to buy a traditional manual with a clutch pedal, even though the DCT is quicker. If you don't like shifting, you may prefer a DCT, even if you don't shift it, because it's more efficient.
The best way to determine how much you like the technology is to test it out. Go to an Audi dealership and drive a TT fitted with this transmission. Try it on both surface roads and highway driving and see what you think. For the best comparison, arrange to test drive a manual transmission model over the same routes. These back-to-back comparisons will give you the best feel and allow an informed decision. Take a car-enthusiast friend, if you want to, and you can compare notes.
