The university competition teams of Baja SAE have the mission of creating prototypes of Mini Baja type vehicles every two years and their great challenge is to reconcile performance and economy. The selection of the right transmission system is essential for the good performance of the vehicle in the tests which it is submitted. Thus, to develop a competitive prototype, structural analysis and optimization tools, such as topological optimization, are useful and have become increasingly present in component improvement studies. To maximize the performance of the Mini Baja vehicle in question, it is crucial to optimize the gears of the reduction gearbox, aiming at reducing its mass. To carry out the topological optimization of the gearbox crown, it is necessary to gather all the geometric and material parameters of the structure, acquire a 3D model of the component to be optimized, define its boundary condition and loads based on the most critical condition that the part is submitted, configure a mesh and perform a structural analysis. After the optimization, it was necessary to model the final geometry in the Solidworks software and carry out a validation of the structure. All steps were detailed in the present work. Topology modeling was developed in SolidWorks software and simulations were performed in Ansys Workbench software.