A gear shift is a fixture in a vehicle which allows the driver to select the gear ratio most appropriate for the speed and conditions. Also known as a gear selector, gear lever, or simply shifter, the gear shift interfaces with the gear box in the vehicle's drivetrain. The design of the shifter can vary widely, depending on what type of vehicle is involved, and whether the transmission is manual or automatic.
In a manual transmission car, drivers have the option of selecting between a number of preset gear ratios with the gear shift. This design allows drivers to save wear on the engine by selecting the appropriate gearing. For example, fifth gear is an excellent choice for high speeds, but it is not a good choice when starting a car. The shifter also allows drivers to select a reverse gear for times when they need to back up. In automatic transmission vehicles, drivers can usually select between a basic drive gear, a park gear, a neutral gear, and a reverse gear. Some automatic transmissions also have an overdrive gear for high speeds, and one to two lower gears for low speeds and unique driving conditions.
A classic place for the gear shift to be mounted is in the center console of the vehicle. The car will usually have a map of the gears so that drivers know which way to move the shifter to access a particular gear. Some cars also have light up displays which indicate which gear is currently selected. Cars may also have shifters on the steering column of the vehicle, a popular choice historically when automobile manufacturers wanted to be able to create front bench seats. Some cars use paddle shifters mounted on either side of the wheel which allow people to pace up or down through the gears.
Operation of the gear shift depends, again, on the vehicle involved. With some manual transmission vehicles, drivers need to activate a clutch pedal to disengage the gear box while they change gears. Other types of vehicles may allow drivers to push a button for the same effect, and with some vehicles, using the clutch is not necessary. In automatic transmission cars, the car will do much of the shifting work for the driver, and sometimes all of it, depending on the car.
When learning to drive, the gear shift is one of the first things drivers are familiarized with, as they need to know how to operate it to drive a car safely. As drivers become familiar with driving and specific cars, they can refine their use of the shifter, and learn to identify problems with the car's gearing or transmission which might require the attention of a mechanic.