Abstract: The invention relates to a hydrodynamic transmission system comprising at least one pump and a bladed turbine arranged to form a toroidal fluid circuit.The leading edges of the blades of the pump and turbine are inclined relative to the corresponding radial plane, and the blades are designed in such a way as to extend the path followed by the streams of fluid nearest the centre relative to the path followed by the streams of fluid furthest away from the centre. There is thus obtained a reduction in the shock and friction losses to improve performance and increase the starting torque.Disclosed application is to automobile vehicles.