For a view of the oil flow diagrams, refer to the 1996 TURM
manual.
In order to obtain the 4-3 downshift, the PCM receives an input signal
from the TP Sensor at increased throttle openings. This causes the PCM to
de-energize the 1-2 solenoid.
1-2 Shift Solenoid (1-2 SS) Valve: When the 1-2 SS Valve de-energizes, spring force holds the 1-2 shift
valve to the extreme right.
2-3 Shift Solenoid (2-3 SS) Valve: When the 2-3 SS Valve de-energizes, signal B pressure exhausts at the
solenoid. This allows a spring force to move the 2-3 shift valve to the extreme
right.
2-3 Shift Valve: The third clutch feed pressure from the 2-3 shift valve is shut off and
an exhaust port is opened at the 2-3 shift valve. This exhausts the third
clutch fluid as the fluid leaves the third clutch accumulator. This causes
the direct clutch to release, shifting the transmission into second
gear.
Direct Clutch: Exhausting third clutch fluid unseats the #8 checkball. This allows for
a rapid exhausting of the third clutch apply fluid at the 2-3 shift valve.
Third Clutch Accumulator: As fluid exhausts from the third clutch accumulator, fluid also exhausts
through the unseated #8 check valve and exhausts at the 2-3 shift valve.