Heavy automotive vehicles and automobiles are, almost exclusively, equipped with automatic hydrodynamic transmissions. This article is devoted to one of the possibilities to control the operation of hydrodynamic transmissions through partially filling the torque converter with liquid. The investigation was centred on torque converters with two-phase flows, namely oil-air. There are proposed theoretical, numerical models and an experimental facility, testing rig, was erected.The obtained results are in the hydrodynamic field (velocities and pressures) in the torus and the characteristic curves of the two-phase flow hydrodynamic transmission.