Speed gear change responsive engine torque reducing system

A device is provided for reducing the engine torque when shifting a speed-change gear transmission connected downstream of an internal combustion engine. A final engine torque control element is connected to a control device which cause the final control element to reduce the engine torque dependent on certain operating conditions dictated by speed and load of the internal combustion engine and upon the occurrence of a switching signal, with interposition of at least one timing element. To obtain precise timing between shifting and engine intervention, the arrangement is made such that the switching signal is triggered synchronously to the torque reversal at a lockable reaction gear element of a planetary wheel gear involved in the shifting so as to cause the final control element to reduce the engine torque without any time delay.