The design of hydrodynamic torque converter impeller is a complex problem that can be solved if the whole set of individual steps is carried out, starting from input data selection to determination of the model sections of the blade. For that reason, fast as well as efficient solution of inverse flow problem can be carried out only by using numerical techniques to solve fluid flow problems. The method developed in this paper, based on free vortex design, involves the linking of meridional and blade-to-blade solutions. A basic assumption used for predicting flow in the meridional plane of the hydrodynamic transmissions impeller is an axisymmetric flow. In accordance with the Bauersfeld method, the design of the impeller blade is performed in an iterative manner using the relationships between velocity components and geometrical blade parameters. Particular attention in the paper is paid to the determination of a functional law of the energy interchange from the inlet to the outlet in the pump and turbine impeller in hydrodynamic transmissions. Finally, a design example for the pump impeller blade is presented.