Gearboxes, also known as transmissions, convert engine rotational power to the wheels while modifying torque and speed. These assemblies are utilized in all vehicles with internal combustion engines, and increasingly with electric drivetrains. Internal components include precisely machined gears, shafts, bearings, and synchronizers to facilitate smooth and efficient power transfer. Modern gearboxes frequently incorporate planetary gearsets for increased efficiency and compact size, alongside electronically controlled actuators for automated shifting. Robust housings and lubrication systems are critical for managing heat and ensuring long-term durability under high stress. Variations include manual, automatic, continuously variable (CVT), and dual-clutch designs, each employing distinct mechanical principles.