On Opel cars establish various hydrotransformers. All of them have marking at an end face which points to compatibility of the transformer with a transmission of the same marking.
The hydrotransformer is located between the engine and a transmission, serves for torque transfer from the engine to a box as means of hydrodynamic movement of a stream of working liquid. For this purpose the engine puts in action the oil pump of the hydrotransformer. The pump wheel being at the same time a casing of the transformer, will transform energy of the engine to kinetic energy of working liquid which influences a turbine wheel.
Pump and turbine wheels rotate with different speed. Therefore, for example, at a troganiye from a place factor of transformation very high then with increase in frequency of rotation of a turbine wheel it goes down. However even on big speeds there is certain "sliding" of liquid. Even at high frequency of rotation of a cranked shaft of the engine only 85 % of a torque are transferred to a shaft of a box. Therefore the engines completed with an automatic transmission, spend slightly more fuel, than engines with a mechanical box. This shortcoming is eliminated by means of the blocking coupling.