Overdrive Range - Second Gear

Overdrive Range - Second Gear:

OVERDRIVE RANGE - SECOND GEAR

"A" SHIFT SOLENOID - OFF
INPUT CLUTCH - APPLIED
FORWARD BAND - APPLIED
"B" SHIFT SOLENOID - ON
INPUT SPRAG - OVERRUNNING
1/2 SUPPORT ROLLER CLUTCH - HOLDING
SECOND CLUTCH - APPLIED

To obtain second gear, the PCM receives input signals from the Vehicle Speed Sensor (VS Sensor), Throttle Position Sensor (TP Sensor) and other engine sensors, to determine the precise moment to "de-energize" or "turn off current" to "A" shift solenoid (315). When this occurs, line pressure to the 1-2 shift valve (318) exhausts through the solenoid allowing spring pressure to move the valve. D-4 pressure at the valve during first gear operation can now enter the 2nd fluid passage. 2nd fluid feeds to the No. 2 checkball (372) and seats the checkball forcing the fluid through a feed orifice before applying the 2nd clutch. At the same time, 2nd clutch fluid is fed to the 1-2 accumulator piston (136) and strokes the piston up against spring pressure and 1-2 accumulator fluid pressure, cushioning 2nd clutch apply. 1-2 accumulator fluid is then forced through the 1-2 accumulator passage and exhausts at the 1-2 secondary accumulator valve (347).

"A" Shift Solenoid (315): De-energizes, allowing line pressure to exhaust through the solenoid.

1-2 Shift Valve (318): With "A" shift solenoid off, spring pressure moves the valve allowing D-4 pressure to enter the 2nd fluid passage directing 2nd fluid to the No. 2 checkball.

No. 2 Checkball (372): Located in the channel plate (400) 2nd fluid seats the checkball and is forced through an orifice into the 2nd clutch passage to apply the 2nd clutch.

1-2 Accumulator Piston (136): Cushions the apply of the 2nd clutch using 2nd clutch fluid to force the piston against spring force and 1-2 accumulator fluid.

Secondary 1-2 Accumulator Valve (347): Regulates the exhaust rate of 1-2 accumulator fluid during the apply of the 2nd clutch.