When the gear selector lever is moved to the REVERSE (R) position (from the PARK position) the following changes occur in the transmission's hydraulic and electrical systems.
With the manual valve in the REVERSE position, line (2) pressure is directed into the reverse (22) fluid circuit.
Reverse (22) fluid pressure, at the primary regulator valve plunger, boosts line (2) pressure for the additional torque requirements in REVERSE. Throttle signal (10) fluid pressure from the line pressure control solenoid valve (SLT) acting on the primary regulator valve plunger also helps determine line (2) pressure in REVERSE depending on throttle position and other TCM input signals.
Reverse (22) fluid pressure is routed to the #7 accumulator check valve assembly where it passes into the reverse clutch (23) circuit. Reverse (22) fluid pressure moves the check valve against spring force in order to cushion the apply of the low and reverse clutch.
Reverse clutch (23) fluid passes through the M1 shift valve into the low and reverse clutch (24) fluid circuit.
Low and reverse clutch (24) fluid is routed to the low and reverse clutch piston to apply the low and reverse clutch plates.
The normally closed reverse SS valve assembly is energized, allowing fluid pressure in the S5 signal (18) fluid circuit to exhaust through the solenoid.
Reverse (22) fluid seats the reverse shift ball check valve against the drive (19) fluid passage and enters the drive or reverse (20) fluid passage.
S5 signal (18) fluid is exhausted from the shift pressure relay valve and spring force moves the valve to the released position to allow drive or reverse (20) fluid to enter the direct clutch feed 1 (27) fluid circuit.
Direct clutch feed 1 (27) fluid passes through the M1 shift valve into the direct clutch feed 2 (28) fluid circuit.
Direct clutch feed 2 (28) fluid passes through the M2 shift valve into the direct clutch (29) fluid circuit.
Direct clutch (29) fluid pressure is routed to the #1 accumulator check valve assembly and moves the check valve against spring force in order to cushion the apply of the direct clutch.
Direct clutch (29) fluid is routed to the direct clutch piston to apply the direct clutch plates.
The normally closed 1-2, 2-3, reverse SS valve assembly is 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.