A powertrain is a system of mechanical parts in a vehicle that takes the power, or output, of the engine and, through specific gear ratios, slows it and transmits it as torque. Through the driveshaft, the engine’s torque is transmitted to the wheels of the vehicle, which, when applied to road, moves the body. Simply put, a powertrain is made up of a transmission system and a driveshaft.The mechanism that transmits the power developed by the engine of the automobile to the driving wheels is called the transmission system (or Power train).It provides a varied leverage between the engine and the drive wheels. It also provides the connection and disconnection of engine with rest of power train without shock and smoothly.The average person is most familiar with the powertrain of their car, which creates energy in the engine, which is transferred to the transmission. Main objective of this project is to design a powertrain system for a truck engine by manual calculation and computer aided designing.