A gear shift, also known as a gear selector or transmission shifter, is a mechanism used in vehicles with manual or semi-automatic transmissions to change the gear ratio of the transmission.

The gear shift allows the driver to manually select different gears, which alters the amount of power and torque delivered to the vehicle’s wheels. Shifting gears is necessary to keep the engine operating within an optimal rpm (revolutions per minute) range for efficient power delivery and fuel economy.

In a manual transmission, the gear shift lever is connected to the transmission via a linkage system. Moving the lever to different positions engages different gear sets inside the transmission. This allows the driver to control the gear ratio and power transfer.

The specific design and operation of a gear shift can vary depending on the type of transmission, but the basic function is to give the driver control over the vehicle’s gearing in order to match the power needs for different driving conditions.