Usually attached to the engine and needed to enable the wide range of speeds required of a modern vehicle, from crawling around town to cruising motorways.

The word gearbox is generally used for a manual while the word transmission usually describes an auto.

A manual gearbox has between four and six speeds while autos have anything from four to eight speeds.

Most modern electronic autos also have a manual-shift function, enabling the driver to change gears via the main centre shifter or with steering wheel paddles.

These are often misleadingly called semi-automatics but should perhaps be called manumatics.