Abstract: An oil pressure supply path to a transmission is changed over using a spool valve comprising a spool which displaces in conjunction with a selector lever of the transmission. The displacement of the spool is detected by an inhibitor switch. By supporting the inhibitor switch directly by the spool valve, the spool displacement position and inhibitor switch output signal always precisely correspond. Therefore, it is unnecessary to adjust the relative position of the spool valve and inhibitor switch unlike the case where these members are supported separately in the transmission.

Abstract: A shift capacity control system for an automatic transmission is constructed to determine a state of an engine speed difference after occurrence of a shift command, determine a propriety of a shift capacity of the automatic transmission in response to the state determined, and control an engagement capacity of a friction element to be operated during a period of shifting in response to the propriety determined.