Our research includes the transmission mechanism of the wind turbine and the calculation of losses, such as loss of mechanical ventilation and friction loss and the loss of lubrication between the gear teeth design. Aims and access to high reliability work and thus obtain high efficiency and taking advantage of electronic programs, We observed that each type of previous losses have an impact on the overall loss of Gearbox, Depending on the working conditions, For example, at low speeds, loss of friction between the teeth is a great percentage of the total loss, And thus controls the overall efficiency of the transport system, while at high speeds noticed this low percentage of loss, while the loss of lubrication and ventilation rate rose.