Overdrive Range - Fourth Gear (Converter Clutch Applied)

Overdrive Range - Fourth Gear (Converter Clutch Applied):

OVERDRIVE RANGE - FOURTH GEAR (CONVERTER CLUTCH APPLIED)

SOLENOID "A" - ON
SECOND CLUTCH - APPLIED
1/2 SUPPORT ROLLER CLUTCH - OVERRUNNING
SOLENOID "B" - OFF
THIRD CLUTCH - APPLIED/NOT EFFECTIVE
FORWARD BAND - APPLIED
PWM SOLENOID - ON
THIRD ROLLER CLUTCH - OVERRUNNING
TCC SOLENOID - ON
FOURTH CLUTCH - APPLIED

To obtain fourth gear, the PCM receives input signals from the Vehicle Speed Sensor (VSS) and Throttle Position Sensor (TPS) in order to "energize" or "turn on current" supply to solenoid "A" (315). When energized, line pressure is directed into the solenoid "A" passage to the 3-4 shift valve (362). Solenoid "A" pressure shifts the valve against spring pressure allowing 3rd fluid to enter the 4th and 4th clutch fluid passages. 4th fluid seats #10 checkball (372) and forces it through a feed orifice to stroke the 3-4 accumulator piston (428) while applying the 4th clutch. 3-4 accumulator fluid on the spring side of the piston is forced through the 3-4 accumulator pin (426) into the 3-4 accumulator passage and exhausts at the 3-4 accumulator valve (350).

Solenoid "A" (315): Energizes to prevent fluid from exhausting out of the line passage and solenoid "A" passage.

1-2 Shift Valve (318): Is held against solenoid "A" by spring pressure and solenoid "B" off fluid pressure at the end of the valve.

3-4 Shift Valve (362): When shifted against spring force, it allows 3rd fluid to enter the 4th and 4th clutch fluid passages. 4th fluid seats #10 checkball (372) and is forced through a feed orifice before stroking the 3-4 accumulator piston (428) and applying the fourth clutch.

#10 Check ball (372): Located in the valve body (300), it forces 4th fluid through a feed orifice into the 4th clutch passage to stroke the 3-4 accumulator piston (428).

3-4 Accumulator Piston (428): Cushions the apply of the 4th clutch by using 4th clutch fluid to stroke the piston against spring force and 3-4 accumulator fluid.

3-4 Accumulator Valve (350): Controls the rate of exhaust of 3-4 accumulator fluid during 4th clutch apply.