Modern automotive technology is getting so advanced, and the timeline for development so short that an item exclusive to the sacred province of the upper echelon of motorsport a few years ago can be found in economical hatchbacks today – quite literally. Volkswagen’s seven-speed Direct Shift Gearbox (DSG) transmission is just such a technology. Offering the best of both manual and automatic standard transmissions, the DSG dual-clutch transmission is now available in the VW Golf and Golf Plus with seven speeds.
For those not intimately familiar with VW’s DSG technology, the basic concept is relatively simple to grasp. Imagine a manual transmission, but instead of one gearset there are two – one for the even gears, another for the odds – and each has its own clutch. That clutch is computer controlled, as is the gear selection, so that while you are in second gear and accelerating, the computer has preselected third on the other gear shaft and only has to disengage the clutch from the active shaft and engage the clutch on the inactive shaft to change gears, allowing a seamless transmission of power between gears. It works in reverse for downshifts, with the computer handling the rev-matching as well. In the modern DSG, the two gear shafts are not side-by-side, but concentric, one outside the other.
Source: Motor Authority