The key difference between a manual and an automatic transmission is that the manual transmission locks and unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic transmission, the same set of gears produces all of the different gear ratios. The planetary gearset is the device that makes this possible in an automatic transmission.

One gearbox contains the ratios for 1st, 3rd & 5th, while the other has 2nd, 4th & 6th. Intelligent predictive electronic control pre-selects the next gear and when the driver requests the shift the drive is passed from one gearbox to the other by use of the two clutches. Volkswagen (parent owner of Lamborghini) has also recently introduced sequential transmission to the Lamborghini Gallardo. BMW also has a system simply called "SMG" (an abbreviation for sequential manual gearbox), but it is not a true sequential, just a modified H-pattern gearbox which uses separate electronically controlled actuators on each of the 3 selector rails. One should not confuse the Porsche Tiptronic transmission with sequential transmissions either. Tiptronic is an automatic transmission which allows the driver to select gears.