Abstract: An embodiment provides a shift inhibitor apparatus. At least a portion of the range actuating assembly is moveable between a range first ratio and a range second ratio. The portion of the range actuating assembly is moveable, at least in part, in response to a fluid pressure. The range chamber is selectively in fluid communication with a vent. The shift inhibitor includes a main section neutral interlock having an interlock chamber. At least a portion of the main section neutral interlock is moveable between a first condition and a second condition. The interlock chamber is selectively in fluid communication with the vent. The range chamber can be exhausted such that the range section is selectively switched from the first ratio to the second ratio. The interlock chamber can be exhausted such that the main section neutral interlock is selectively switched from the first condition to the second condition.

Abstract: A robust control (10) for a pressurized-fluid-operated, three-position shift actuator piston assembly (12). The system requires only a single controlled source of pressurized fluid (44) to provide movement to and retention in a selected one of three axially displaced positions (D, N, OD). A solenoid-controlled valve (42) is controlled by pulse width modulation. Current applied to the solenoid coil is controlled (46), voltage (V) applied to the solenoid coil is sensed and used as a control parameter and/or a relatively light detent (48, 50) biases the assembly to a neutral (N) position to provide a robust control.