Power transmissions in motor vehicles are one of the key elements of the overall quality of the whole system and therefore special attention should be paid to this issue. In order to find the simplest solution for general purposes that fully complies with the requirements for the application on motor vehicles of the categories M and N, a test bench is designed with the configuration in the form of "closed-loop" which allows testing of virtually all elements and assemblies of the power transmission in a wide range of operating regimes and load conditions. Application of the configuration with two gearbox transmissions and a larger number of shafts and cardanshafts gives the possibility of parallel testing of various solutions in the early stages of transmission development, which significantly speeds up the process of finding the optimal solution. Implementation of the brake mechanism in the contour allows testing of differential mechanisms by changing regimes without stopping the test bench. Simple procedure enables variation of driveshaft’s angles to a considerable extent, covering most of the real operating regimes. This configuration of the test bench contains all the elements of the transmission and provides quick insight into the critical points that may lead to a system failure.