Abstract: A shift control mechanism for a change speed transmission, or a change speed transmission section, having selectively axially movable gears, the selective axial movement of which is effective to cause engagement and disengagement of the axially moved gear, is provided. The shift control mechanism is utilized for a four speed transmission, or transmission section, and comprises a first shift fork fixed to a first shift rail, a second shift fork fixed to a second shift rail and a third shift fork fixed to a third shift rail. The shift rails are independently axially movable, the first and second shift rails are concentrically received in a first bore of a housing, the third shift rail is received in the second bore of a housing, and positive interlock means are provided to prevent simultaneous displacement of any two or more of the shift rails.