A Simulink model has been developed using an old layout given me by prof. Carlo Rosso, this improved model is able at the end to calculate the dynamic force between two meshing gears, having as inputs only two parameters that are rotational speed and torque. The main difficulties regarded matching the experimental data given to me by the team with results coming out of my Simulink model in order to make it reliable and to make it as close as possible to the real deal in terms of accuracy. The task has be accomplished using just factory Simulink blocks com- bined in subsystems dealing with theoretical calculations of displace- ments, damping, non-linearities and forces; at last was also evaluated the effect of torque inversion and the way which it can be included in the model.