The main purpose of this paper is to confirm the structural soundness of a two-stage helical gearbox used in BAJA all terrain vehicle (ATV). The gearbox utilizes two consecutive helical gear stages to transmit power from an input shaft to an output shaft. Gearbox provides speed and torque conversions from the engine to the wheels. Gearbox is the main component in the transmission by which speed of the vehicle is controlled and provide the required amount of torque. In this paper CAD software was used to create a three-dimensional model of the transmission system and Finite Element Analysis (FEA) was performed to predict the distribution of stress, deformation and strain in gearbox components such as gears, shafts, bearings and housing. The results of FEA provide valuable insights into the performance potential and structural behavior of the two-stage helical gearbox.