An automotive drivetrain is a mechanical system that is used to connect the transmission to the drive axles. An internal combustion engine produces torque that is transferred through a drivetrain to the wheels that provide acceleration.
While sophisticated four- and all-wheel-drive vehicles may require additional components and a more complicated drivetrain system, the system operates basically the same way in all cars and trucks. Drivetrains are comprised of couplings, gear differentials and shafts. Once a driver presses down on the accelerator, the drivetrain transfers the torque created by the vehicle's engine to the drive axles that power the wheels to make the vehicle move.