Temperature control of the gear oil

The gear oil in automatic transmissions has an optimal working temperature
range, within which a high level of comfort is achieved simultaneously with
a very long service life. Compared with the temperature development of the
coolant, the adaptation while driving is delayed and the gear oil thus only
attains the optimal temperature on longer rides. This delay results in
considerably increased fuel consumption as a result of the related friction
losses. Hot coolant causes an active heating of the gear oil which then
counteracts this delay and ensures that greater comfort and efficient energy
conversion are achieved more quickly. In addition to this, with the use of
a thermostat and the appropriate circuit, it is possible to not only actively
heat up, but also to cool or regulate the temperature of the gear oil.