The drivetrain includes the transmission, the driveshaft, the axles, and the wheels. Simply put, it works in conjunction with the engine to move the wheels. The drivetrain system is an essential component of a vehicle and the transmission is an integral part of the drivetrain.
The drivetrain and the transmission are actually two very different concepts. The main function of the transmission is similar to the chain on a bicycle: it keeps the engine turning in time with the wheels, regardless of what gear the vehicle is in. The drivetrain represents everything that is behind the transmission involved in propelling the vehicle. The main function of the drivetrain is basically to convey power from the vehicle’s engine, through the transmission to the drive wheels on the vehicle to control the amount of torque. “Torque” is turning or twisting force.