Abstract: Disclosed is a shift control for an automatic transmission adapted to shift speed ranges by coupling or decoupling of the friction coupling elements mounted on the transmission mechanism.The coupling force of the friction coupling elements is subjected to feed-forward control during a preset period after a signal of instruction for shifting was given. A control value for the feed-forward control is determined in accordance with control value characteristics which vary from a given initial value at a constant change rate.After the preset period, coupling force of the friction coupling element is feed-back controlled by of actual revolutions of an input shaft of the transmission mechanism. A final control value for the feed-back control is determined by determining a target change rate in the feed-back control by an amount of change in revolutions number of the input shaft of the transmission mechanism estimated by shifting and a set time for the feed-back control.

Abstract: The invention relates to a method for preventing, in a vehicle transmission coacting with a system for automatic gear selection, the selection of an operationally incorrect gear in the case where a signal representing a vehicle wheel rotational speed, e.g. during braking of the vehicle, does not constitute a correct representation of the vehicle speed. There is thus calculated in the system the wheel rotational speed change, which is compared with a predetermined retardation value. If the retardation limiting value is exceeded, an operative circuit or the like is activated for ensuring that an incorrect gear selection is prevented, e.g. by selecting neutral gear.