For defining CV power trains in on- and off-road commercial vehicles which are an optimum for the whole system it is necessary to improve all components in a system and not one for each other. Exemplarily new combustion engines realise the same power at lower engine speeds. Such changes have a direct effect on the required series of ratios of the transmission, on the torque which has to be transferred and also on the number of speeds where a high efficiency is of advantage because of being used in high time shares. With this the number of gear changes will be increased. To prevent speed losses of the vehicle these shifts should be carried out as power shifts. IAV proposes a systematical advanced development process that considers the whole complexity as early as possible.