Reverse Shift Solenoid (SS) Valve Assembly (S5)
WARNING: This page is about a different car, the 2009 Pontiac Torrent and 2009 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
Line (2) fluid passes through orifice #5 into the S5 signal (18) fluid circuit. The normally closed reverse SS valve assembly is OFF, causing fluid pressure to build-up in the S5 signal (18) fluid circuit.