This paper presents vibration test and dynamics modeling of an automotive suspension system. Concretely, the vibration tests are conducted in three translational directions, and in several kinds of input levels. The dynamical modeling by MBD is carried out base on the experiment. It is shown that the vibration level dependency is explained by changes of the equivalent stiffness and damping coefficients at the shock absorber. An analytical example by the constructed model is also shown with respect to the level dependency.