Manual Valve
WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The gear selector lever mechanically moves the manual valve. While this is occurring, the valve directs line pressure through the PRND4 fluid passage into the reverse circuit. Reverse fluid then routes to the pressure regulator valve and to the reverse orifice bypass valve. Reverse fluid then passes through orifice #6. The fluid seats checkball #7 before routing to the 1-2 shift valve.