3 was operated on the test bench for half an hour at a constant input drive speed of 1700 revolutions per minute which corresponds to approximately 70 km h and the temperature behavior and the drag torque were measured fig2 shows the profile with 1700 min u2212 1 of the two measured variables of temperature t of the operating fluid in degrees celsius and drag torque s in nm on the ordinate and the time on the abscissa the trial is started with a cold transmission at approximately 23 u00b0 c the corresponding curves are t 1 and s 1 for the transmission filled with oil and t 2 and s 2 for the transmission filled with the operating fluid according to the invention it is apparent that during the operating time the temperature t 1 rises significantly more steeply and reaches 57 u00b0 c while the temperature t 2 rises slowly to somewhat above 35 u00b0 c the drag torque is the sum of all the unloaded losses in the transmission mainly friction losses and churning losses the drag torque s 1 in the transmission with the oil filling is initially very high above 5 5 nm because of.