In standard tractors, the mechanical PTO is used to drive high power demanding implements. Its current design as a mechanic, manually switchable transmission enables efficient power transmission, but does not provide the variability needed for automated optimization of the operating points of the engine and the implement. In this paper the development and testing of an electro-mechanic power spilt transmission as PTO drive for agricultural machinery is being presented. This transmission offers variable speed control with efficiencies of 90% in the main operating range.