Important:: The complete hydraulic circuit for Manual Third gear range has been omitted. This is because Manual Third operation is identical to Drive Range. However, in Manual Third the TCM prevents the transmission from upshifting into Fourth gear regardless of operating conditions. Also, in Manual Third the R321 fluid circuit at the manual valve is fed by line pressure but does not affect the transmission operation.

A manual 3-2 downshift can be accomplished by moving the gear selector lever into the Manual Second (2) position when the transmission is operating in Third gear. If vehicle speed is below approximately 120 km/h (75 mph), the TCM will downshift the transmission into Second gear. Above this speed, the TCM will keep the shift solenoids in a Third gear state and the transmission in Manual Second - Third Gear until vehicle speed decreases appropriately. Also, once in second gear, the TCM prevents the transmission from upshifting to third gear. In Manual Second the transmission upshifts and downshifts normally between First and Second gears. The following text explains what is different during a manual 3-2 downshift (from Drive Range - Third Gear to Manual Second - Second Gear) as opposed to a forced 3-2 downshift in Drive Range.

Manual Valve: D32 fluid at the manual valve feeds the 1-2 fluid circuit.

Mode Switch (Electrical): Located on the selector shaft (61), it signals the TCM that the selector lever and manual valve are in the Manual Second (2) position.

Overrun Lockout Valve: 1-2 fluid pressure assists spring force and hydraulically prevents the valve from shifting into the Fourth gear position, thereby preventing Fourth gear.

Checkball #4: 1-2 fluid pressure unseats the ball and, in addition to D32 fluid, feeds the D32/1-2 fluid circuit. The checkball #4 is located in the main case.

Low Pressure Control Valve: 1-2 fluid pressure moves the valve against spring force and orificed 1-2 regulated fluid. This action regulates 1-2 fluid into the 1-2 regulated fluid circuit. 1-2 regulated fluid pressure is approximately one half that of 1-2 fluid pressure and line pressure. This provides for a softer apply of the 3rd clutch when the transmission downshifts to First gear (remember that the 3rd clutch is applied in Manual Second - First Gear).

1-2/3-4 Shift Solenoid: The TCM keeps the solenoid energized (ON) as in Third gear. This keeps the solenoid open and D32/1-2 fluid pressure acting on the end of the 1-2/3-4 shift valve.

1-2/3-4 Shift Valve: In the Second and Third gear position the valve blocks 1-2 regulated fluid. This fluid is for use in First gear in Manual Second and Manual First. Otherwise the valve operates the same as in Third gear.

Manual Second Gear