If vehicle speed becomes greater than 12 km/h (7 mph) while the transmission is operating in REVERSE, the TCM commands the following changes to the transmission's hydraulic and electrical systems in order to inhibit reverse operation and prevent damage to the transmission.
The reverse, 1st SS valve assembly is energized, causing fluid pressure to build-up in the S1 signal (14) fluid circuit.
S1 signal (14) fluid is routed to the U1 shift valve and passes through the valve into the reverse inhibit (52) fluid circuit.
Reverse inhibit (52) fluid is routed to the M1 shift valve and applies the valve against spring force.
The reverse SS valve assembly is de-energized, causing fluid pressure to build-up in the S5 signal (18) fluid circuit.
S5 signal (18) fluid is routed to the shift pressure relay valve and applies the valve against spring force.
When the M1 shift valve is shifted to the applied position, reverse clutch (23) fluid is blocked and low and reverse clutch (24) fluid exhausts through the valve allowing the low and reverse clutch assembly to release.
Exhausting low and reverse clutch (24) fluid is routed into the B5 control 2 (38) fluid passage at the M1 shift valve, the B5 control 1 (37) fluid passage at the solenoid relay valve, the reverse control (25) fluid passage at the B5 control valve, and on to the shift pressure relay valve where it exhausts.
The 1-2, 2-3, reverse SS valve assembly is de-energized. However, because there is no fluid supplied to the circuit, the 1-2, 2-3, reverse SS valve assembly has no effect in REVERSE INHIBIT.
When the M1 shift valve is shifted to the applied position, direct clutch feed 1 (27) fluid is blocked and direct clutch (29) fluid pressure exhausts, allowing the direct clutch assembly to release.
Exhausting direct clutch (29) fluid passes through the M2 shift valve into the direct clutch feed 2 (28) fluid circuit and on to the M1 shift valve where it exhausts.