The aim of this master thesis is an estimation of stiffness and damping parameters through variational analysis in NVH behavior for a tractor model. The starting point was a 7-DOFs tractor model, completely analyzed through the software LUPOS, evaluating the results in terms of natural frequencies and movements (i.e. bouncing, rolling, and pitching movements). Afterward, the analysis has taken into account further elements such as double wishbone suspension, the presence of passengers, and other geometrical and inertial details linked to a real-world tractor. Therefore, a variational analysis has been computed in order to fit stiffness parameters according to expected natural frequencies of different modes. Similarly, FRF comparative analysis has been computed thanks to both experimental data and TFMs LUPOS.