Today's powertrains are becoming more and more complex due to the increasing number of gear box types requiring gearshift patterns like conventional (equipped with GSI) and automatic-manual transmissions (AT, AMT), double clutch and continuous variable transmissions (DCT, CVT). This increasing variety of gear boxes requires a higher effort for the overall optimization of the powertrain. At the same time, it is necessary to assess the impact of different powertrains and control strategies on CO₂ emissions very early in the development process. The optimization of Gear Shift Patterns (G.S.P.) has to fulfill multiple constraints in terms of objective customers' requirements, like driveability, NVH, performance, emissions and fuel consumption.For these reasons, RENAULT and AVL entered an engineering collaboration in order to develop a dedicated simulation tool: CRUISE GSP. One of the major tasks of CRUISE GSP is to provide representative gearshift patterns for all available gearboxes on the market (including manual transmissions for GSI applications) at the very early stage of the powertrain development permitting to discriminate technical solutions.Once a prototype exists, CRUISE GSP helps to refine and optimize the gearshift patterns for immediate usage during gear box tuning in the vehicle.Being entirely integrated into AVL CRUISE™ (AVL's simulation tool for vehicle system simulation and driveline analysis), CRUISE GSP allows the efficient optimization of the gearbox shift patterns for different driving styles and thus the reduction of transmission calibration effort in the development process. By combining AVL CRUISE™ and CRUISE GSP with the engine tuning optimization tool AVL CAMEO™ a global Powertrain optimization (i.e., including both engine maps and gearshift patterns) can now be considered as a future perspective.AVL powertrain engineering has been using CRUISE GSP on various calibration projects. For their specific needs AVL have implemented additional functionality to CRUISE GSP. The GSP WIZARD is a result of this development. The specific focus of AVL powertrain engineering is to have a continuous process from simulation to in-vehicle calibration. In the process the calibration tool is used by the calibration engineer to speed up the in-vehicle development and plausibility check results quickly. This helps to avoid a negative impact on fuel economy and performance while working on driveability.