Hydraulic control system for an automatic transmission

A hydraulic control system for a motor vehicle transmission includes a pressure regulation subsystem and a manual valve assembly in fluid communication with the pressure regulation subsystem. The manual valve assembly is moveable between at least park, neutral, drive, and reverse positions. A default disable valve assembly is in fluid communication with the manual valve assembly, a default disable solenoid valve assembly, and a default select valve assembly. A one-way valve may be provided to permit hydraulic fluid to flow to a second-priority hydraulic circuit when in a default mode of operation. A combined main regulation and priority valve may be provided to pressurize line pressure as a first priority, pressurize the second-priority hydraulic circuit as a second priority, and to feed excess pressure to a decrease-pressure circuit as a third priority.