A gearbox is a mechanical device that transmits power from an engine to the wheels of a vehicle. It adjusts the speed and torque of the engine's output, allowing the vehicle to move efficiently at different speeds. Gearboxes can be found in various types of vehicles, including cars, trucks, and motorcycles, and they come in different designs, such as manual and automatic. The main components of a gearbox include gears, shafts, and bearings. Gears are arranged in a specific sequence to provide different gear ratios, which determine how fast the vehicle can go and how much power is available for acceleration. Proper functioning of the gearbox is essential for optimal performance and fuel efficiency in vehicles like cars and trucks.