Jeep XJ. Manual — part 423
TRANSMISSION VALVE BODY COMPONENTS
DESCRIPTION
Transmission operating pressure is supplied to the
clutch and brake apply circuits through the transmis-
sion valve body. The valve body consists of an upper
body, lower body, separator plate and upper and
lower gaskets (Fig. 14). The various spool valves,
sleeves, plugs and springs are located within the two
body sections.
The manual valve, 1–2 shift valve, primary regula-
tor valve, accumulator control valve, check balls, and
oil strainers are located in the lower body section
(Fig. 15). The remaining control and shift valves plus
check balls and one additional oil strainer are located
in the upper body section (Fig. 16).
TRANSMISSION VALVE BODY SOLENOIDS
The solenoids are mounted on the valve body and
operated by the TCM. The solenoids control operation
of the converter clutch and shift valves in response to
input signals from the module.
Fig. 14 Two–Section Transmission Valve Body
1 – UPPPER BODY
2 – UPPER GASKET
3 – SEPARATOR PLATE
4 – LOWER GASKET
5 – LOWER BODY
Fig. 15 Upper Body Components
1 – ACCUMULATOR CONTROL VALVE
2 – 1–2 SHIFT VALVE
3 – MANUAL VALVE
4 – PRIMARY REGULATOR VALVE
5 – LOWER BODY
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DESCRIPTION AND OPERATION (Continued)
OPERATION
MANUAL VALVE
The manual valve is operated by the gearshift link-
age. The valve diverts fluid to the apply circuits
according to shift lever position (Fig. 17).
Fig. 16 Lower Body Components
1 – DOWNSHIFT PLUG
2 – LOCK-UP RELAY VALVE
3 – SECONDARY REGULATOR VALVE
4 – UPPER BODY
5 – CUT-BACK VALVE
6 – THROTTLE VALVE
7 – LOW COAST MODULATOR VALVE
8 – SECONDARY COAST MODULATOR VALVE
9 – 2–3 SHIFT VALVE
10 – 3–4 SHIFT VALVE
11 – THROTTLE CAM
Fig. 17 Manual Valve
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DESCRIPTION AND OPERATION (Continued)
PRIMARY REGULATOR VALVE
The primary regulator valve (Fig. 18) modulates
line pressure to the clutches and brakes according to
engine load. The valve is actuated by throttle valve
pressure.
During high load operation, the valve increases
line pressure to maintain positive clutch and brake
engagement. At light load, the valve decreases line
pressure just enough to maintain smooth engage-
ment.
THROTTLE VALVE AND DOWNSHIFT PLUG
The throttle valve and downshift plug (Fig. 19)
control throttle pressure to the primary regulator
valve.
The downshift plug and throttle valve are operated
by the throttle valve cam and throttle cable in
response to engine throttle position. Throttle valve
pressure is also modulated by the cut–back valve in
second, third and fourth gear ranges.
CUT–BACK VALVE
The cut–back valve (Fig. 20) helps prevent exces-
sive pump pressure buildup in second, third and
fourth gear. The valve is actuated by throttle pres-
sure and by line pressure from the second brake. The
valve also helps regulate line pressure by controlling
the amount of cut–back pressure to the throttle
valve.
SECONDARY REGULATOR VALVE
The secondary regulator valve (Fig. 21) regulates
converter clutch and transmission lubrication pres-
sure. When primary regulator valve pressure exceeds
requirements for clutch engagement or transmission
lubrication, the secondary regulator valve is moved
upward exposing the drain port. Excess pressure
then bleeds off as needed. As pressure drops, spring
Fig. 18 Primary Regulator Valve
1 – THROTTLE PRESSURE
2 – LINE PRESSURE (FROM MANUAL VALVE “R” RANGE)
3 – LINE PRESSURE (FROM PUMP)
4 – CONVERTER PRESSURE TO CONVERTER CLUTCH RELAY
VALVE
5 – LINE PRESSURE
6 – CONVERTER PRESSURE (TO SECONDARY REGULATOR
VALVE)
7 – DRAIN
8 – DRAIN
Fig. 19 Throttle Valve And Downshift Plug
1 – LINE PRESSURE CABLE
2 – THROTTLE VALVE CAM
3 – DOWNSHIFT PLUG
4 – THROTTLE VALVE
5 – THROTTLE PRESSURE (TO PRIMARY REGULATOR VALVE)
6 – LINE PRESSURE
7 – CUT-BACK PRESSURE (FROM CUT-BACK VALVE)
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DESCRIPTION AND OPERATION (Continued)
tension moves the valve downward closing the drain
port.
CONVERTER CLUTCH RELAY VALVE
The converter clutch relay valve (Fig. 22) controls
fluid flow to the converter clutch. The valve is oper-
ated by line pressure from the 1–2 shift valve and is
controlled by solenoid valve number three.
1–2 SHIFT VALVE
The 1–2 shift valve (Fig. 23) controls the 1–2
upshifts and downshifts. The valve is operated by the
No. 2 valve body solenoid and line pressure from the
manual valve, second coast modulator valve and the
2–3 shift valve.
When the transmission control module deactivates
the solenoid, line pressure at the top of the valve
moves the valve down closing the second brake accu-
mulator feed port. As the solenoid is activated and
the drain port opens, spring force moves the valve up
exposing the second brake feed port for the shift to
second gear.
2–3 SHIFT VALVE
The 2–3 shift valve (Fig. 24) controls the 2–3
upshifts and downshifts. The valve is actuated by the
No. 1 valve body solenoid and by line pressure from
the manual valve and primary regulator valve.
Fig. 20 Cut–Back Valve
1 – THROTTLE PRESSURE
2 – CUT-BACK PRESSURE TO THROTTLE VALVE
3 – CUT-BACK VALVE
4 – SECOND BRAKE LINE PRESSURE
Fig. 21 Secondary Regulator Valve
Fig. 22 Converter Clutch Relay Valve
1 – SOLENOID VALVE NO. 3
2 – LINE PRESSURE (FROM 1–2 SHIFT VALVE)
3 – CONVERTER PRESSURE
4 – DRAIN
5 – LINE PRESSURE (FROM PUMP)
6 – CONVERTER CLUTCH RELAY VALVE
7 – TO CONVERTER CLUTCH (DISENGAGED)
8 – TO OIL COOLER
9 – TO CONVERTER CLUTCH (ENGAGED)
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DESCRIPTION AND OPERATION (Continued)
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