The development and the test of complex electronic control units for power train control systems (with focus on DCT transmission control) requires a well established, functional and feasible development process and modern development tools to fulfil all target requirements including cost and project time requirements. This development tasks are no longer imaginable without the usage of simulation tools. Whereat simulation has been used for Hardware-In-Loop (HIL) testing and the software has been and hand-written for years, simulation tools become more important in all areas of development. In fields like system development, software development, software testing and software calibration, simulation tools are used to improve the execution of development tasks.This paper describes the implementation of a tool-driven and model-based software development process with focus on the model-based software design and testing possibilities as well as the usage of profound simulation capabilities and the preparation of the development process for the development of functional safety according ISO 26262. Based on examples from existing development projects for double clutch transmission control systems, the implementation of the development process and the usage of software tools will be shown.