Rubber bushings are extensively-used linking parts in a vehicle chassis that allow to filter noise and vibration. They influence much, however, the transient behaviour of the vehicle, such as its steering performance. Therefore building a multibody simulation with a relevant description of the rubber bushings is useful to describe the significant characteristics of the vehicle's steering behaviour. First, a nonlinear time-dependent model describing a rubber bushing's mechanical behaviour is presented. In order to be relevant, the parameters associated with this model are then identified from experimental tests using an adjoint state formulation of the identification problem. The identified values are eventually validated using additional experimental data.