Park or Neutral - Engine Running

Park Or Neutral Engine Running:

PARK OR NEUTRAL ENGINE RUNNING

"A" SHIFT SOLENOID - ON
INPUT CLUTCH - APPLIED (NOT EFFECTIVE)
"B" SHIFT SOLENOID - ON
INPUT SPRAG - HOLDING (NOT EFFECTIVE)

In Park (P) range with the engine running, fluid is pulled from the sump, through the filter (100) and into the oil pump (200). Pump output is regulated by the pressure regulator valve (313) and a "decrease" passage which creates a calibrated output pressure called "line pressure". In PARK (P) range, line pressure is directed to the following components:

Pressure Regulator Valve (313): Regulates pump output in response to modulator pressure, PRN pressure at the reverse boost valve (310) and spring force from the pressure regulator valve springs (311, 312).

Manual Valve (404): Manually controlled through the gear selector lever, it directs line pressure from the pressure regulator valve (313) into the PRN passage in PARK, REVERSE or NEUTRAL. The manual valve (404) also provides for a hydraulic override of the electronic shift control system in the transaxle for manual third and manual second gear selection.

Modulator Valve (34): Controlled by the vacuum modulator, it regulates modulator pressure inversely to engine vacuum. Modulator pressure is directed to the line boost valve (304), 1-2 accumulator valve (341), secondary 1-2 accumulator valve (347), 2-3 accumulator valve (343) and 3-4 accumulator valve (350).

2-3 Shift Valve (357): In PARK range, line pressure passes through the 2-3 shift valve (357) and feeds the input clutch feed passage. Line pressure then passes through the 3-4 shift valve (362), around the No. 3 checkball (372, located in the channel plate) to apply the input clutch. Although the input clutch is applied and the input sprag is holding, they are not effective because neither the forward band assembly (688) or the reverse band assembly (615) are applied.

Converter Clutch Valve (335): Line pressure and spring force holds the valve against the converter clutch solenoid (315) allowing converter feed pressure to the release side of the converter clutch pressure plate. In this position, converter clutch apply pressure feeds into the cooler passage, through the cooler and into the lube circuit.

*Converter Clutch Regulator Valve (330): Biased by modulator and [1][2]Torque Converter Clutch (TCC) accumulator pressure, it uses line pressure to provide regulated apply fluid to the converter clutch valve (335).

Pulse Width Modulated (PWM) Solenoid (325): Electrically controlled by the Powertrain Control Module (PCM), it regulates PWM feed pressure into the PWM passage to the converter clutch regulator valve (330). This arrangement provides for precise control of regulated converter clutch apply pressure. Since the PWM solenoid (325) is not energized until 3rd gear operation, full line pressure passes through the solenoid to the converter clutch regulator valve (330).

"A" Shift Solenoid (315): Controlled by the Powertrain Control Module (PCM), it is energized (On) in PARK range. Line pressure moves the 1-2 shift valve (318) against spring pressure and directs line fluid into the "A" shift solenoid passage. "A" shift solenoid fluid is then directed to the 3-4 shift valve (362).

"B" Shift Solenoid (315): Controlled by the Powertrain Control Module (PCM), it is energized (On) in PARK range and directs line pressure into the "B" shift solenoid passage. "B" shift solenoid fluid is directed to: the 4-3 manual downshift valve (360) and moves the valve against spring pressure, and also the 3-2 manual downshift valve (356).

Pressure Relief Valve (321): Exhausts line pressure above 1,690-2,480 kPa (450-360 psi).

Line Pressure Tap (38): Allows line pressure to be monitored with a gage.

* Applications that do not use a Pulse Width Modulator (PWM).