Jeep Cherokee 2000 Service Manual - page 1141
3–4 SHIFT VALVE
The 3–4 shift valve (Fig. 25) is operated by the No.
2 solenoid and by line pressure from the manual
valve, 2–3 valve and primary regulator valve.
Energizing the No. 2 solenoid causes line pressure
at the top of the 3–4 valve to be released through the
solenoid valve drain port. Spring tension moves the
valve up exposing the overdrive clutch accumulator
feed port to apply the clutch.
De–energizing the solenoid causes the drain port to
close. Line pressure then moves the valve down
exposing the overdrive brake accumulator feed port
for the shift to fourth gear.
In the 1–2 or 3 gearshift lever positions, line pres-
sure from the 2–3 shift valve is applied to the lower
end of the 3–4 valve. This holds the valve upward,
closing off the overdrive brake feed port preventing a
shift into fourth gear.
SECOND COAST MODULATOR VALVE
The second coast modulator valve (Fig. 26) momen-
tarily reduces line pressure from the 1–2 shift valve.
This cushions application of the second coast brake.
The valve is operative when the shift lever and man-
ual valve are in the 3 position.
LOW COAST MODULATOR VALVE
The low coast modulator valve (Fig. 27) momen-
tarily reduces line pressure from the 2–3 shift valve;
this action cushions application of the first/reverse
Fig. 25 3–4 Shift Valve
1 – TO OVER DRIVE BRAKE ACCUMULATOR
2 – LINE PRESSURE (FROM PRIMARY REGULATOR VALVE)
3 – LINE PRESSURE (FROM PRIMARY REGULATOR VALVE)
4 – TO OVERDRIVE CLUTCH ACCUMULATOR
Fig. 26 Second Coast Modulator Valve
1 – LINE PRESSURE (FROM 1–2 SHIFT VALVE)
2 – LOW COAST MODULATOR PRESSURE SECOND COAST
BRAKE
XJ
AW–4 AUTOMATIC TRANSMISSION
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DESCRIPTION AND OPERATION (Continued)