After First 1-2 Shift

Overdrive Range, First Gear (After First 1-2 Shift)





Overdrive Range, First Gear

When the gear selector lever is moved to the Overdrive range position (D), from the Neutral (N) position, after the first 1-2 shift has occurred, the following changes occur to shift the transmission into Overdrive Range - First Gear.
Manual Valve: In the Overdrive position the manual valve routes line pressure into the D432 fluid circuit. D432 fluid is routed to the 1-2 shift valve and to the 3-4 shift valve.

Forward Clutch Applies
#6 and #7 Ball Check Valves: D432 fluid seats the #6 ball check valve and passes through orifice #15 into the forward clutch fluid circuit. D432 fluid also passes by the spring loaded #7 ball check valve to feed the forward clutch circuit as necessary to help control forward clutch apply.
#5 Ball Check Valve: Forward clutch fluid seats the #5 ball check valve and passes through orifice #17 into the coast clutch feed circuit.
Forward Clutch Assembly: Forward clutch fluid is routed to the forward clutch piston to apply the forward clutch plates.

Coast Clutch Applies
2-3 Shift Solenoid (SS) Valve: The 2-3 SS valve is energized, allowing feed limit fluid to enter the 2-3 signal fluid circuit. 2-3 signal fluid overcomes 2-3 shift valve spring (372) force and moves the 2-3 shift valve (371) to the applied position.
1-2 Shift Control Valve and 1-2 Shift Valve: 2-3 signal fluid is routed to the 1-2 shift control valve (366) and moves the valve against 1-2 shift control valve spring (367) force to the applied position. This allows feed limit fluid to enter the FDL fluid circuit. FDL fluid is routed to the 1-2 shift valve (387) and moves the valve against 1-2 shift valve spring (388) force to the applied position to block D432 fluid at the valve.
3-4 Shift Control Valve and 3-4 Shift Valve: 2-3 signal fluid is also routed to the 3-4 shift control valve (346) and moves the valve against 3-4 shift valve spring (344) force to the applied position. This allows D432 fluid to enter the 123 fluid circuit at the 3-4 shift valve (345).
#4 Ball Check Valve: 123 fluid seats the #4 ball check valve and passes through orifice 16. This orifice helps to control coast clutch apply.
4-5 Shift Valve: Orificed 123 fluid is routed to the 4-5 shift valve (374) where it passes into the coast clutch fluid circuit.
Coast Clutch Assembly: Coast clutch fluid is routed to the coast clutch piston to apply the coast clutch plates.

Fluid Pressure Directed in Preparation for a Shift to Second Gear
1-2 Shift Valve: D432 fluid is routed to the 1-2 shift valve (387) where it is blocked by the valve in preparation for an upshift to second gear.