In this contribution, the change of global quasi-static stiffness and hysteresis properties between uniaxial and spatial loads for a box-shaped filled natural rubber gearbox mount is experimentally recorded. Based on the results of the investigation, a rheological component model is developed for use in virtual load data determination within the multibody system simulation, including a parameterisation procedure using particle swarm optimisation. A modelling focus is on the representation of the change of uniaxial properties due to spatial loads. The quality for the virtual load data determination of the developed modelling approach is evaluated in comparison to currently industrially used methods.