A four-speed automatic transmission is a vehicle transmission system with four gears and an automatic shifter that does not require the driver to work the gearshift manually. Four-speed transmissions were common in vehicles from the 1960s through the 1980s, but have largely been replaced by five-speed transmissions in newer vehicles.
Gears govern the amount of power produced by the car's engine, which affects how fast the vehicle travels and how easily it negotiates hills. Lower gears are better for driving at lower speeds, and higher gears are more efficient for driving at high speeds. The four gears of a four-speed transmission do not include other settings controlled by the car's gear shift, such as reverse, park or four-wheel drive.