Drive Range, Manual 1ST (From Drive, Manual 2ND)

Drive Range - Manual First (From Manual Second):

When the gear selector lever is moved to the MANUAL FIRST range (1), the manual valve (404) allows line pressure to enter the Lo passage. Lo fluid pressure is sent to the #7 checkball (372), which seats against the Lo-First fluid passage. Based on Powertrain Control Module (PCM) input signals from the VS Sensor, the TP Sensor, and the Lo-First lockout speed calibration, the 1-2 shift solenoid valve is energized (turned ON). This allows line pressure to enter the 1-2 shift solenoid passage. The 1-2 shift solenoid valve fluid then holds the 1-2 shift valve (318). The fluid is also directed to the 3-4 shift valve (362). The second clutch is released by second clutch applied fluid exhausting to the #2 checkball (372), forcing the fluid through the exhaust orifice into the second fluid passage. Second fluid is the directed through the 1-2 shift valve (318) and into the third fluid passage where the fluid exhausts at the 2-3 shift valve (357). Simultaneously, Lo fluid is directed through the 1-2 shift valve (318) into the Lo-First fluid passage. Lo-First fluid is send to the pressure regulator valve (313) in order to boost line pressure. At the same time fluid is sent to the Lo blow-off valve (407). Lo-First fluid also seats the #4 checkball against the third clutch passage and directs the fluid into the third clutch/Lo-First passage in order to apply the third clutch.

MANUAL VALVE (404)
The gear selector lever moves the manual valve, allowing line pressure to enter the Lo fluid passage.

#7 CHECKBALL (372)
The #7 checkball is located in the valve body (300). The checkball directs Lo fluid to the 1-2 shift valve (318).

1-2 SHIFT VALVE (318)
When shifted against spring force, the 1-2 shift valve allows Lo fluid to enter the Lo-First passage to the pressure regulator valve (313). During release of the second clutch, exhausting second fluid passes through the valve and enters the third fluid passage.

PRESSURE REGULATOR VALVE (313)
The pressure regulator valve boosts line pressure using Lo-First fluid pressure.

LO BLOW-OFF VALVE (407)
The Lo blow-off valve is a relief valve that exhausts excess Lo fluid pressures above 448 kPa (65 psi) in the third clutch applied circuit.

#4 CHECKBALL (372)
The #4 checkball is located in the channel plate (400). The checkball seats against third clutch fluid allowing Lo-First fluid to enter the third clutch fluid passage and apply the third clutch.

1-2 SHIFT SOLENOID VALVE (315)
Line pressure feeds into the energized 1-2 shift solenoid passage and on to the 3-4 shift valve (357).

#2 CHECKBALL (372)
The #2 checkball is located in the channel plate (400). The checkball forces exhausting second clutch applied fluid through an orifice into the second clutch passage and to the 1-2 shift valve (318).