Abstract: A vehicle driven by a super charged engine has a gear transmission that is automatically shifted between drive ratios under the joint control of vehicle speed and engine load demand, modified by a loading signal pressure derived from the engine carburetor to correctively influence the change in drive ratio so as to accommodate a super charged type of engine. Such loading signal pressure is applied to a shift valve of the transmission control system independently of control pressure reflecting vehicle speed and engine load demand in order to correctively modify the pressure control exercised during the drive ratio change interval.

Abstract: Two concurrently operated hydraulic brakes of an automotive transmission, actuated in an intermediate-speed ("second gear") position, are filled under the control of a slide valve whose slider in a normal position admits fluid at high rate to both brakes and thereafter assumes an unstable throttling position in which the fluid pressure gradually builds up in them to a value causing an associated plunger to return the slider to normal. One of the brakes, which is only unidirectionally effective, remains actuated also upon an upshift into a high-speed position ("third gear") whereas the other, bidirectionally effective brake is released upon such upshift under the control of a shift valve which cuts off the fluid flow to the latter brake and establishes a drainage path therefor by passing the slide valve.