It's not that easy to come to terms with todays gearboxes, especially if one includes the automatic gearboxes. The borders between the two have gradually become blurred, this is because there are purely manual gearboxes, with and without clutch operation, as well as automatic gearboxes which allow manual intervention in certain modes, or also those which implicitly require manual intervention.
There's no way to tell, by looking at the the operational controls, what type of gearbox is installed. If they look like those in an automatic, they could also belong to an automated gearbox (sequential). However, even this description is not well defined, because, in this case, a manual gearbox can be combined with a single- or with a double-clutch.
It becomes completely confusing, if one includes the, as far as the concept is concerned, infinitely variable gearbox with and without pulling-off element, because in the course of experience with customers, the development is going back to the graded box. On the horizon, and already in practice, can be seen, electric motors, which together with a single set of planet gears and without any clutch at all, replace the gearbox.
Gearboxes can be classified as coaxial- and as non-coaxial gearboxes . Previously one could allocate 3 shafts to the coxial- and 2 to the non-coaxial. In the meantime however, there are the compact-construction gearboxes, which are non-coaxial and, nonetheless, have three shafts (without reverse gear). Also the amount of gears seems to be exploding, a max. of seven speeds at the moment, for direct-change gearboxes and eight-speeds for the torque-converter automatics.
Not considered at present are, all-wheel-drive and truck-gearboxes, which can generate, from the combination of two, three, or four gears, almost any amount of speeds (32?). The acting auxiliary drive, together with various in- and retarders can cause confusion. One thing is certain, the more complicated, and the more speeds a gearbox has, the more the assistance of electronics is needed. 11/09