During two summers I worked with developing and programming a system toolin Python for transmissions. The tool had an interactive GUI and a window to see the built up model in real time while working with it. A complete gear box could be built up, including different shafts, gears and bearings. By defining load cases, all forces acting on the system were automatically calculated, making it possible to create system model input-files to Abaqus to perform more advanced calculations, e.g. bearing misalignment. I also implemented the possibility to perform life time calculations on the bearings according to different fatigue ISO-standards.