This paper discusses the implementation of deformable ring gears in Multi-Body-Simulation-Models (MBS-Models) of planetary gearboxes using the example of a Wind Turbine (WT). For this purpose an add-on to the MBS-Software SIMPACK was developed and tested by the project partners BOSCH REXROTH and the INSTITUTE FOR MACHINE ELEMENTS AND MACHINE DESIGN at RWTH-AACHEN UNIVERSITY (IME). The presented research includes a measurement campaign on a test rig owned by BOSCH REXROTH to obtain data for a validation of the newly developed add-on.