1995 JEEP CHEROKEE automatic transmission

Fig. 1 30RH/32RH Automatic Transmission
21 - 68 30RH/32RH AUTOMATIC TRANSMISSIONJ

driven by the torque converter. The converter is con-
nected to the engine crankshaft through the drive-
plate.
The pressure regulator valve maintains line pres-
sure. The regulator valve is located in the valve body.
The amount of line pressure developed is controlled
by throttle pressure, which is dependent on the de-
gree of throttle opening.
The governor valve is operated by the transmission
output shaft. Governor pressure increases approxi-
mately in proportion to vehicle speed.
The throttle valve determines line pressure and
shift speed. The throttle valve also controls upshift
and downshift speeds by regulating pressure in con-
junction with throttle position.
Shift Valves
The manual valve is operated by the gearshift link-
age and provides the operating range selected by the
driver.
The 1-2 shift valve provides automatic 1-2 or 2-1
shifts and the 2-3 shift valve provides automatic 2-3
or 3-2 shifts. The kickdown valve provides forced 3-2
or 3-1 downshifts depending on vehicle speed. Down-
shifts occur when the throttle is opened beyond
downshift detent position which is just before wide
open throttle.
The 2-3 valve throttle pressure plug provides 3-2
downshifts with varying throttle openings and de-
pending on vehicle speed. The 1-2 shift control valve
transmits 1-2 shift pressure to the accumulator pis-
ton to control kickdown band capacity on 1-2 upshifts
and 3-2 downshifts.The shuttle valve has two functions. First is fast
front band release and smooth engagement during
lift-foot 2-3 upshifts. The second is to regulate front
clutch and band application during 3-2 downshifts.
Clutches-Bands-Servos-Accumulator
The front/rear clutch pistons and servo pistons are
actuated by line pressure. When line pressure is re-
moved, the pistons are released by spring tension.
On 2-3 upshifts, the front servo piston is released
by spring tension and hydraulic pressure. The accu-
mulator controls hydraulic pressure on the apply side
of the front servo during 1-2 upshifts and at all
throttle openings.
Converter Clutch Controls
Converter clutch operation is controlled by the
power train control module, and by the solenoid and
clutch module on the valve body. The solenoid is op-
erated by a relay on the engine compartment side of
the dash panel.
Activating the solenoid opens a vent allowing fluid
to flow into the clutch module. When line pressure
exceeds tension of the module valve springs, the
module valves open. This allows fluid to be chan-
neled to the converter clutch through the reaction
shaft support and transmission shaft.
Gearshift And Park Lock Controls
The gearshift lever provides six operating positions:
Park (P), Reverse (R), Neutral (N), and the D, 2 and
1 forward drive ranges.
Manual 1 position provides first gear only. Overrun
braking occurs in 1 range when the throttle is re-
leased. Upshifts are not provided in 1 range.
Manual 2 range provides first and second gear. A
1-2 upshift will take place but a 2-3 upshift will not
occur.
D position provides 1-2, 2-3 upshifts and 3-2 and
3-1 downshifts.
Park position allows the park rod to move the park
pawl into engagement with the park gear. This pre-
vents rotation of the transmission output shaft. The
park lock mechanism is only engaged when the shift
lever is in the Park detent.
A park/neutral position switch controls engine
starting. The switch is designed to allow engine
starts only in park or neutral positions.
Fig. 2 Transmission Identification
J30RH/32RH AUTOMATIC TRANSMISSION 21 - 69

30RH/32RH TRANSMISSION DIAGNOSIS
INDEX
page page
Air Pressure Test......................... 74
Analyzing the Road Test.................... 71
Converter Housing Leak Diagnosis............ 75
Converter Stall Test........................ 74
Diagnosis Guides and Charts................ 77
Effects of Incorrect Fluid Level............... 71
Fluid Level Check......................... 70Gearshift Cable/Linkage Adjustment........... 71
General Information....................... 70
Hydraulic Pressure Test.................... 72
Preliminary Diagnosis...................... 70
Road Test............................... 71
Transmission Throttle Valve Cable Adjustment.... 71
GENERAL INFORMATION
Automatic transmission problems are generally a
result of:
²poor engine performance
²incorrect fluid level
²incorrect throttle valve cable adjustment
²incorrect band adjustment
²incorrect hydraulic control pressure adjustments
²hydraulic component malfunctions
²mechanical component malfunctions.
Begin diagnosis by checking the easily accessible
items such as fluid level, fluid condition and control
linkage adjustment. A road test will determine if fur-
ther diagnosis is necessary.
Procedures outlined in this section should be per-
formed in the following sequence to realize the most
accurate results:
²Preliminary diagnosis
²Check fluid level and condition
²Check control linkage Adjustment
²Road test
²Stall test
²Hydraulic pressure test
²Air pressure tests
²Leak test
²Analyze test results and consult diagnosis charts
PRELIMINARY DIAGNOSIS
Two basic procedures are required. One procedure
for vehicles that are driveable and an alternate pro-
cedure for disabled vehicles (will not back up or move
forward).
Vehicle Is Driveable
(1) Check fluid level and condition.
(2) Adjust throttle cable and gearshift linkage if
complaint was based on delayed, erratic, or harsh
shifts.
(3) Road test vehicle and note transmission operat-
ing characteristics.(4) Perform stall test if complaint is based on slug-
gish, low speed acceleration or abnormal throttle
opening needed to maintain normal speeds with
properly tuned engine.
(5) Perform hydraulic pressure tests.
(6) Perform air pressure test to check clutch-band
operation.
Vehicle Is Disabled
(1) Check fluid level and condition.
(2) Check for broken, disconnected throttle linkage.
(3) Check for cracked, leaking cooler lines, or loose,
missing pressure port plugs.
(4) Raise vehicle, start engine, shift transmission
into gear and note following:
(a) If propeller shafts turn but wheels do not,
problem is with differential or axle shafts.
(b) If propeller shafts do not turn and transmis-
sion is noisy, stop engine. Remove oil pan, and
check for debris. If pan is clear, remove transmis-
sion and check for damaged drive plate, converter,
oil pump or input shaft.
(c) If propeller shafts do not turn and transmis-
sion is not noisy, perform hydraulic pressure test to
determine if problem is a hydraulic or mechanical.
FLUID LEVEL CHECK
Transmission fluid level should be checked monthly
under normal operation. If the vehicle is used for
trailer towing or similar heavy load hauling, check
fluid level and condition weekly.
Fluid level is checked with the engine running at
curb idle speed, the transmission in Neutral and the
transmission fluid at normal operating temperature.
FLUID LEVEL CHECK PROCEDURE
(1) Transmission fluid must be at normal operating
temperature for accurate fluid level check. Drive ve-
hicle if necessary to bring fluid temperature up to
normal hot operating temperature of 82ÉC (180ÉF).
(2) Position vehicle on level surface. This is ex-
tremely important for accurate fluid level check.
(3) Start and run engine at curb idle speed.
21 - 70 30RH/32RH TRANSMISSION DIAGNOSISJ

(3) If vehicle is equipped withauxiliary cooler,
test cooler flow as described in step (2).
TRANSMISSION COOLER REVERSE FLUSHING
The flushing procedure applies to standard and
auxiliary coolers alike. Although pressure equipment
is preferred, reverse flushing can be performed with
hand operated equipment as follows.
(1) Disconnect cooler pressure and return lines at
transmission (Figs. 34 and 35).
(2) Remove and discard drainback valve. Install
fabricated hose and fitting in place of valve.
(3) Position drain pan under cooler pressure line to
catch material flushed through cooler and lines.(4) Reverse flush cooler using hand operated suc-
tion gun filled with mineral spirits. Insert gun nozzle
(or hose) into cooler return line. Then force mineral
spirits into line and through cooler.
(5) Continue reverse flushing until fluid coming
out of cooler pressure line is clear.Replace cooler if
fluid cannot be pumped through.
(6) Clear flushing materials from cooler and lines
with short pulses of compressed air. Insert air gun
nozzle into cooler return line and continue short air
pulses until all fluid is cleared from cooler and lines.
(7) Pump one quart of fresh automatic transmis-
sion fluid through cooler and lines before reconnect-
ing lines.
(8) Install new drainback valve in pressure line.
(9) Check and adjust transmission fluid level as
described in this section.
Fig. 34 Cooler Line Fitting Identification (30RH/
32RH)
Fig. 35 Cooler Line Routing (YJ)
21 - 114 30RH/32RH IN-VEHICLE SERVICEJ

AW-4 AUTOMATIC TRANSMISSION
CONTENTS
page page
AW-4 AUTOMATIC TRANSMISSION........ 165
AW-4 IN-VEHICLE SERVICE.............. 182
AW-4 TRANSMISSION DIAGNOSIS......... 176
AW-4 TRANSMISSION OVERHAUL......... 201AW-4 TRANSMISSION REMOVAL AND
INSTALLATION....................... 198
GENERAL INFORMATION................ 165
GENERAL INFORMATION
INDEX
page page
Components and Operation................. 166
Description............................. 165
First/Second/Third/Reverse Components....... 168
Fourth Gear Overdrive Components.......... 167
Geartrain Operation and Application Charts..... 169Hydraulic System........................ 169
Recommended Fluid and Capacity........... 166
Torque Converter........................ 167
Transmission Identification.................. 166
Transmission Ranges and Shift Lever Positions . . 166
DESCRIPTION
AW-4 Transmission Overhaul
The AW-4 is a 4-speed, electronically controlled au-
tomatic transmission (Fig. 1). The AW-4 is used in XJ
models with a 4.0L engine.
Running gear consists of an oil pump, planetary
gear sets, clutch and brake units, hydraulic accumu-
lators, a valve body with electrical solenoids and a
transmission control module (TCM). Cables are usedfor shift and throttle pressure control. A park/neutral
position switch permits engine starting in Park and
Neutral range only.
The valve body solenoids are controlled by signals
from the transmission control module (TCM). Signal
sequence is determined by vehicle speed and throttle
position.
Fourth gear is an 0.75:1 ratio overdrive range.
First, second, third and reverse gear are conventional
Fig. 1 AW-4 Automatic Transmission
JAW-4 AUTOMATIC TRANSMISSION 21 - 165

ranges. Third gear ratio is 1:1. A separate planetary
gear set provides overdrive operation in fourth gear.
TRANSMISSION RANGES AND SHIFT LEVER
POSITIONS
The AW-4 transmission has six ranges and shift le-
ver positions. Park, Reverse and Neutral are conven-
tional and mechanically operated. The 1-2, 3 and D
ranges provide electronically controlled shifting.
The 1-2 position provides first and second gear
only. The 3 position provides first, second and third
gear.
The D range provides first through fourth gear.
Overdrive fourth gear range is available only when
the shift lever is in D position (Fig. 2).
TRANSMISSION IDENTIFICATION
The transmission I.D. plate is attached to the case
(Fig. 3). The plate contains the transmission serial
and model numbers. Refer to the information on this
plate when ordering service parts.
RECOMMENDED FLUID AND CAPACITY
Recommended and preferred fluid for the AW-4
transmission is Mopar Dexron IIE/Mercon.
Mopar Dexron II can be used but only in emer-
gency situations where Mercon fluid is not available.
Approximate refill capacity for the AW-4 is 8.0 li-
ters (16.9 pints or 8.45 quarts).
COMPONENTS AND OPERATION
ELECTRONIC CONTROLS
The AW-4 is electronically controlled in 1, 2, 3 and
D ranges. Controls consist of the transmission control
module (TCM), valve body solenoids and various sen-
sors. The sensors monitor vehicle speed, throttle
opening, shift lever position and brake pedal applica-
tion.
TRANSMISSION CONTROL MODULE (TCM)
The module determines shift and converter clutch
engagement timing based on signals from sensors.
The valve body solenoids are activated, or deacti-
vated accordingly.
The TCM has a self diagnostic program. Compo-
nent and circuitry malfunctions can be diagnosed
with the DRB scan tool. Once a malfunction is noted
and stored in control module memory, it is retained
even after the problem has been corrected. To cancel
a stored malfunction, disconnect and reconnect the
9Trans.9fuse in the module harness.
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.
SENSORS
Sensors include:
²throttle position sensor (TPS)
²transmission speed sensor
²vehicle speed sensor
²park/neutral position switch
²brake switch
The throttle position sensor is mounted on the
throttle body. It electronically determines throttle po-
sition and relays this information to the transmission
control module to determine shift points and con-
verter clutch engagement.
Fig. 2 AW-4 Shift Lever Positions And Transmission
Ranges
Fig. 3 Transmission Identification
21 - 166 AW-4 AUTOMATIC TRANSMISSIONJ

The transmission speed sensor consists of a rotor
and magnet on the transmission output shaft and a
switch in the extension housing or adapter. The sen-
sor switch is activated each time the rotor and mag-
net complete one revolution. Sensor signals are sent
to the transmission control module.
The park/neutral position switch is mounted on the
valve body manual shaft. The switch signals shift
linkage and manual valve position to the transmis-
sion control module through an interconnecting har-
ness. The switch prevents engine starting in all gears
other than Park or Neutral.
The brake switch is in circuit with the torque con-
verter clutch solenoid. The switch disengages the
converter clutch whenever the brakes are applied.
The switch is mounted on the brake pedal bracket
and signals the transmission control module when
the pedal is pressed or released.
TORQUE CONVERTER
A three element torque converter is used for all ap-
plications. The converter contains an impeller, stator,
and turbine.
The AW-4 converters are all equipped with a con-
verter clutch mechanism. The clutch consists of a
sliding clutch piston, clutch springs and the clutch
disc material (Fig. 4). The clutch provides optimum
torque transfer and economy when engaged.
The clutch disc is attached to the converter front
cover. The clutch piston and clutch springs are at-
tached to the turbine hub. The springs dampen en-
gine firing impulses and loads during the initial
phase of converter clutch engagement.
Clutch engagement is controlled by transmission
valve body solenoid number three and by the con-
verter clutch relay valve. The solenoid channels line
pressure to the clutch through the relay valve at
clutch engagement speeds.Torque converter clutch engagement occurs in sec-
ond gear in 1-2 position; third gear in 3 position and
third and fourth gear in D position.
FOURTH GEAR OVERDRIVE COMPONENTS
The overdrive system consists of the input shaft,
one-way clutch, planetary sun gear, ring gear, plane-
tary carrier, clutch and overdrive brake (Fig. 5). The
overdrive elements are controlled and applied
through transmission valve body solenoid number
two.
In overdrive fourth gear, the brake prevents the
overdrive sun gear from turning. During operation,
the overdrive elements operate as follows:
Fig. 4 Torque Converter (With Clutch)
Fig. 5 Fourth Gear Overdrive Components
JAW-4 AUTOMATIC TRANSMISSION 21 - 167

The overdrive input shaft and planetary carrier ro-
tate as a unit. The sun gear and overdrive direct
clutch drum are in mesh and operate as a single
unit. The direct clutch splines function as the hub for
the overdrive brake. The one-way clutch outer race is
in mesh with the planetary carrier. The inner race is
fixed to the sun gear shaft.
FIRST/SECOND/THIRD/REVERSE COMPONENTS
First, third and reverse gear components are out-
lined in Figure 6.
The input shaft is meshed with the direct clutch
hub and the forward clutch drum. These elements ro-tate as a unit. The forward clutch hub rotates as a
unit with the front planetary ring gear. The direct
clutch drum is meshed with the forward end of the
planetary sun gear.
The second brake hub serves as the outer race of
one-way clutch No. 1. The clutch inner race is locked
with the front/rear sun gear. The inner race of one-
way clutch No. 2 is splined to the transmission case
and is locked. The outer race rotates as a unit with
the rear planetary carrier.
Fig. 6 First, Second, Third And Reverse Gear Components
Fig. 7 Component Function Chart
21 - 168 AW-4 AUTOMATIC TRANSMISSIONJ