For a view of the oil flow diagram, refer to the 1996 TURM Manual.

When the gear selector lever is moved to the DRIVE range (D), the manual valve (404) allows line pressure to enter the D3 passage. D3 fluid is then directed to the 3-4 shift valve (362) and the fluid moves the valve against 1-2 shift solenoid valve pressure. D3 fluid is also sent to the 2-3 shift valve (357), where the fluid enters the input clutch feed passage. Input clutch feed fluid traces the following path:

1. Through the 3-4 shift valve (362)
2. Into the input clutch passage
3. Seats the #3 checkball (372) against the PRN passage
4. Applies the input clutch.

Fourth clutch application fluid at the fourth clutch is directed to the 3-4 accumulator assembly (421-428) and then to the #10 checkball (372). Exhausting fourth clutch fluid seats the #10 checkball (372) against the fourth passage This directs fluid through an exhaust orifice up to the 3-4 shift valve (362), where the fluid exhausts. Since D3 fluid overrides the 1-2 shift solenoid valve fluid at the 3-4 shift valve (362), a manual 4-3 downshift results, even if the 1-2 shift solenoid valve is energized (turned ON). The normal DRIVE range Fourth gear solenoid state is:

If the PCM receives the appropriate input signals from the VS Sensor and the TP Sensor, the 1-2 shift solenoid valve will de-energize (turn OFF), and the 1-2 shift solenoid valve fluid will then exhaust through the solenoid.

The gear selector lever moves the manual valve, allowing line pressure to enter the D3 passage.

The 2-3 shift valve allows D3 fluid to enter the input clutch feed passage. The valve then directs the fluid to the 3-4 shift valve (362).

The 3-4 shift valve is downshifted when D3 fluid is fed to the valve. In this position input clutch feed fluid enters the input clutch passage.

The #3 checkball is located in the channel plate (400). The checkball is seated against the PRN passage, which allows input clutch fluid to apply the input clutch.

The #10 checkball is located in the valve body (300). The checkball is seated against fourth fluid, which allows fourth clutch fluid to exhaust at the 3-4 shift valve (362).

1-2 shift solenoid valve fluid from the 3-4 shift valve (362) exhausts through a de-energized 1-2 shift solenoid valve. However, this event does not have to occur in order to achieve a manual 4-3 downshift.