Transmission Structure

Transmission: An intermediate device that transmits the motion and power of the prime mover to the working mechanism.
For front-engine, rear-wheel drive vehicles, the engine's torque is transmitted to the rear wheels through the clutch, transmission, universal joint, drive shaft, final drive, differential, and half-shafts. Therefore, the rear wheels are also called drive wheels. The torque applied to the drive wheels exerts a backward force on the ground, which in turn generates a forward reaction force on the drive wheels. This reaction force is the vehicle's driving force. The front wheels of a vehicle generally have no direct power connection to the drivetrain and are therefore called driven wheels.
The composition and layout of the transmission system vary depending on the engine type, installation location, and vehicle application. For example, off-road vehicles often use four-wheel drive, and therefore have a transfer case and other assemblies in their transmission system. In contrast, front-engine, front-wheel drive vehicles do not have drive shafts or other devices in their transmission system.