Abstract: Automatic differential transmission gear particularly suitable for motor vehicles comprising a speed reducing gear box with a reduction planetary gear and a collecting planetary gear. The gear box has two input shafts, one of which is connected with the reduction planetary gear and the second of which is connected with the collecting planetary gear. In one preferred embodiment, the input shaft of the reduction planetary gear is selectively connected firmly or by way of a hydrodynamic element with the input shaft of the automatic differential transmission gear, and the input shaft of the collecting planetary gear is adapted to be connected with the input shaft of the automatic differential transmission gear by a connecting element in the form of two friction clutches.

Abstract: In order to prevent a cyclic repeating of switching of vehicle gears to higher speeds for automatic transmissions at increased running resistances, an electronic control system is provided with a prognostic circuit which predicts the acceleration which can be expected after switching to a higher speed and which allows the switching to higher speeds only if this acceleration is above zero. If an adjusted maximum speed is exceeded, this operation of the prognostic circuit is interrupted.