The purpose of this thesis work has been to analyze the usability and the feasibility formodeling with MathWorks simulation tool Simscape by building a simplified model ofthe automatic gearbox ZF-ECOMAT 4 (HP 504 C / HP 594 C / HP 604 C). It hasbeen shown throughout the thesis how this model is build. First has systemknowledge been acquired by studying relevant literature and speaking with thepersons concerned. The second step was to get acquainted with Simscape and thephysical network approach. The physical network approach that is accessible throughthe Simscape language makes is easy to build custom made components with means ofphysical and mathematical relationships. With this background a stepwise approachbeen conducted which has led to the final model of the gearbox and the validationconcept. The results from this thesis work indicates that Simscape is a powerful tool formodeling physical systems and the results of the model validation gives a good signthat it is possible to build and simulate physical models with the Simscape software.However, during the modeling of the ZF-ECOMAT 4 some things have beendiscovered which could improve the usability of the tool and make the learning curvefor an inexperienced user of physical modeling tools less steep. In particular, a largermodel library should be included from the beginning, more examples of simple andmore complex models, the object-oriented related parts such as own MATLABfunctions should be expanded, and a better troubleshooting guidance.