Abstract: An electrohydraulic speed change system for a load-shiftable gear transmission of an automotive vehicle in which hydraulic devices such as clutches and brakes are operated by electromagnetic actuation of respective valves of the hydraulic system. The speed selection is effected by a series-connected array of switches and the circuit means provided for actuation of the electromagnetic valve includes time-delay networks operating an interrupter switch in series with this array.

Abstract: An automotive transmission with three or four stages corresponding to as many forward speeds, established by the activation of respective hydraulic coupling elements via associated electrical valve-operating switches, includes an individual delay network in the energizing circuit of each valve-operating switch for modifying its response time in dependence on load and on the direction of shift. By this modification an upshift under load or a downshift under pull proceeds with substantially immediate activation of one coupling element upon deactivation of another coupling element, whereas under other circumstances (downshift under load or upshift under pull) an appreciable hiatus occurs between deactivation and activation to take advantage of the intervening speed change.