Device for stabilizing the temperature of the transmission oil of a motor vehicle

A device for controlling temperature of a transmission oil of a motor vehicle having a liquid-cooled vehicle engine and a radiator in which coolant of the liquid-cooled vehicle engine is recoolable, the device comprising:

• a heat exchanger through which the coolant is conducted as a function of temperature, said heat exchanger also being traversed by the transmission oil;
• wherein the coolant supplied to the heat exchanger is miscible in a thermostatic valve from recooled and non-recooled coolant;
• wherein said thermostatic valve comprises at least one control piston formed as an expanding material element, said expanding material element carrying valve plates for changing inflow cross sections of a mixing chamber in a thermostat housing of said thermostatic valve;
• wherein the thermostatic valve is controlled via temperatures of an essentially mixed coolant stream;
• and
• wherein one control piston is provided both in the mixing chamber and in an oil chamber, which is traversed by the transmission oil, of the thermostat housing, and wherein the one control piston provided in the mixing chamber has a free end abutting the one control piston provided in the oil chamber, the free end allowing the pistons to separate from one another.