The Direct Shift Gearbox is a cake-and-eat-it-too tranny of the sort engineers have spent decades striving for—one that combines the efficiency of a manual with the effortlessness of an automatic. We've reported on plenty of automated manuals over the past decade, finding some (the BMW M3's, the Ferrari Enzo's) to perform better than others (the BMW Z4's, the Toyota MR2 Spyder's).
All such systems we've tested to date use conventional manual transmissions to which are mounted little electromechanical gizmos that assume the tasks a driver's wrist, elbow, and left foot would otherwise perform in manipulating a shifter and clutch pedal. Even the quickest-shifting of these still requires a momentary gap in the power delivery, because they all must release the clutch while a new gear is selected. And that has doomed these boxes as a replacement for the conventional automatic in mainstream vehicles.
The dual-clutch concept eliminates the torque gap by releasing the clutch driving one gear just as a clutch connected to the next gear engages. Like so many good ideas that have come into production recently, this one is nothing new. It was first tried at Citroën more than 70 years ago, and it even saw duty in Porsche 962 and Audi Quattro race cars during the mid-'80s. But the primitive electronics of the day made the system difficult to tune for commercially comfortable launches and smooth shifting, and system reliability fell somewhat shy of the four-year/50,000-mile warranty target.
