Overdrive Range - Fourth Gear (Converter Clutch Applied)

Overdrive Range - Fourth Gear (Converter Clutch Applied):

OVERDRIVE RANGE - FOURTH GEAR (CONVERTER CLUTCH APPLIED)

"A" SHIFT SOLENOID - ON
SECOND CLUTCH - APPLIED
1/2 SUPPORT ROLLER CLUTCH - OVERRUNNING
"B" SHIFT SOLENOID - 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 VS sensor and TP sensor in order to "energize" by providing a ground for "A" shift solenoid (315), When energized, line pressure is directed into the "A" shift solenoid passage to the 3-4 shift valve (362). "A" shift solenoid 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).

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

1-2 Shift Valve (318): Is held against "A" shift solenoid by spring pressure and "B" shift solenoid of 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 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 Checkball (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.