1995 JEEP YJ oil pressure

(47) Remove rear servo spring retainer snap ring.
Then remove compressor tools and remove rear servo
spring and piston.
OVERHAUL SERVICE INFORMATION
Inspect the transmission bushings during overhaul.
Bushing condition is important as severely worn, or
scored bushings contribute to low pressures, clutch
slip and accelerated wear of other components.How-
ever, do not replace bushings as a matter of
course. Replace bushings only when they are
actually worn, or scored.
Use recommended tools to replace bushings. The
tools are sized and designed to remove, install and
seat bushings correctly. The bushing replacement
tools are included in Bushing Tool Set C-3887-B or
C-3887-J. The bushing tools are manufactured by
Miller Tool Co. and is available through the dealer
tool program.
Pre-sized service bushings are available for replace-
ment purposes. Only the sun gear bushings are not
serviced. Replace the gear as an assembly if the
bushings are worn, or scored.
Heli-Coil inserts are recommended for repairing
damaged, stripped or worn threads in aluminum
parts. These inserts are available from most automo-
tive jobbers. Stainless steel inserts are preferred.
The use of crocus cloth is permissible where neces-
sary. When used on valves, use care to avoid round-
ing off sharp edges. Sharp edges are vital as they
prevent foreign matter from getting between the
valve and valve bore.
Do not reuse oil seals, gaskets, seal rings, or
O-rings during overhaul. Replace these parts as a
matter of course. Also do not reuse snap rings or E-
clips that are bent or distorted. Replace these parts
as well.Lubricate transmission parts with Mopar ATF
Plus, Type 7176 transmission fluid during overhaul
and assembly.
Use petroleum jelly to hold parts like thrust wash-
ers in place during assembly. Use Mopar Door Ease,
Ru-Glyde, or similar products to lubricate piston
seals and O-rings to ease installation. Petroleum jelly
can also be used to prelubricate parts during reas-
sembly if desired.
TRANSMISSION CASE CLEANING AND
INSPECTION
Clean the case in a solvent tank. Flush the case
bores and fluid passages thoroughly with solvent.
Use compressed air to dry the case and clear the
fluid passages. Be sure all solvent is removed from
the case as well.
Do not use shop towels or rags to dry the case
(or any other transmission component) unless
they are made from lint-free materials. Lint
will readily adhere to case surfaces and trans-
mission components and will circulate through-
out the transmission after assembly. A sufficient
quantity of lint can block fluid passages and in-
terfere with valve body operation.
Inspect the case for cracks, porous spots, worn
bores, or damaged threads. Damaged threads can be
repaired with Helicoil thread inserts. However, the
case will have to be replaced if it exhibits any type of
damage or wear.
Lubricate the front band adjusting screw threads
with petroleum jelly and thread the screw part-way
into the case. Be sure the screw turns freely.
Remount the case in a repair stand after cleaning
and inspection.
OVERRUNNING CLUTCHÐLOW-REVERSE
DRUMÐREAR SUPPORT OVERHAUL
DISASSEMBLING OVERRUNNING CLUTCH/
LOW-REVERSE DRUM
If the clutch assembly came out with the low-re-
verse drum, thread two clutch cam bolts into the
cam. Then lift the cam out of the drum with the bolts
(Fig. 30). Rotate the cam back and forth to ease re-
moval if necessary. Remove the clutch roller and
spring assembly from the race afterward.
CLEANING AND INSPECTION
Clean the overrunning clutch assembly, clutch cam,
low-reverse drum and rear support in solvent. Dry
them with compressed air after cleaning.
Inspect condition of each clutch part after cleaning.
Replace the overrunning clutch roller and spring as-
sembly if any rollers or springs are worn or damaged,
or if the roller cage is distorted, or damaged. Replace
the cam if worn, cracked or damaged.
Fig. 29 Compressing Rear Servo Spring
J30RH/32RH TRANSMISSION OVERHAUL 21 - 125

CAUTION: The pump inner gear is a one way fit.
The bore on one side of the gear inside diameter
(I.D.) is chamfered. Be sure the chamfered side
faces forward (to front of pump).
(6) Install new thrust washer on hub of reaction
shaft support. Lubricate washer with transmission
fluid or petroleum jelly.
(7) If reaction shaft seal rings are being replaced,
install new seal rings on support hub (Fig. 59). Lu-
bricate seal rings with transmission fluid or petro-
leum jelly after installation. Squeeze each ring until
ring ends are securely hooked together.
CAUTION: The reaction shaft support seal rings will
break if overspread, or twisted. If new rings are be-
ing installed, spread them only enough for installa-
tion. Also be very sure the ring ends are securely
hooked together after installation. Otherwise, the
rings will either prevent pump installation, or break
during installation.
(8) Install reaction shaft support on pump housing
(Fig. 60).(9) Align reaction support on pump housing. Use
alignment marks made at disassembly. Or, rotate
support until bolt holes in support and pump housing
are all aligned (holes are offset for one-way fit).
(10) Install all bolts that attach support to pump
housing. Then tighten bolts finger tight.
(11) Tighten support-to-pump bolts to required
torque as follows:
(a) Reverse pump assembly and install it in
transmission case. Position pump so bolts are fac-
ing out and are accessible.
(b) Secure pump assembly in case with 2 or 3
bolts, or with pilot studs.
(c) Tighten support-to-pump bolts to 20 Nzm (15
ft. lbs.).
(d) Remove pump assembly from transmission
case.
(12) Install new oil seal in pump with Special Tool
C-4193 and Tool Handle C-4171 (Fig. 61). Be sure
seal lip faces inward.
(13) Install new seal ring around pump housing.
Be sure seal is properly seated in groove.
(14) Lubricate lip of pump oil seal and O-ring seal
with transmission fluid.
FRONT CLUTCH OVERHAUL
FRONT CLUTCH DISASSEMBLY
(1) Remove waved snap ring and remove pressure
plate, clutch plates and clutch discs (Fig. 62).
Fig. 57 Supporting Pump And Installing Outer Gear
Fig. 58 Pump Inner Gear Installation
Fig. 59 Hub Seal Ring Position
Fig. 60 Assembling Reaction Shaft Support And
Pump Housing
21 - 134 30RH/32RH TRANSMISSION OVERHAULJ

CAUTION: The throttle valve, shuttle valve plug, 1-2
shift valve and 1-2 governor plug are made of
coated aluminum. Aluminum components can be
identified by the dark color of the special coating
applied to the surface (or by testing with a magnet).
DO NOT polish or sand aluminum valves or plugs
with any type of material, or under any circum-
stances. This practice might damage the special
coating and cause the valves and plugs to stick and
bind.
Inspect the valves and plugs for scratches, burrs,
nicks, or scores. Also inspect the coating on the alu-
minum valves and plugs (Fig. 119). If the coating is
damaged or worn through, the valve (or valve body)
should be replaced.
Aluminum valves and plugs should not be sanded
or polished under any circumstances. However, minor
burrs or scratches on steel valves and plugs can beremoved with crocus cloth but do not round off the
valve or plug edges. Squareness of these edges is vi-
tally important. These edges prevent foreign matter
from lodging between the valves, plugs and bore.
Inspect all the valve and plug bores in the valve
body. Use a penlight to view the bore interiors. Re-
place the valve body if any bores are distorted or
scored. Inspect all of the valve body springs. The
springs must be free of distortion, warpage or broken
coils.
Trial fit each valve and plug in its bore to check
freedom of operation. When clean and dry, the valves
and plugs should drop freely into the bores. Valve
body bores do not change dimensionally with use. If
the valve body functioned correctly when new, it will
continue to operate properly after cleaning and in-
spection. It should not be necessary to replace a
valve body assembly unless it is damaged in han-
dling.
Fig. 118 Shift Valves And Pressure Regulator Plugs
J30RH/32RH TRANSMISSION OVERHAUL 21 - 151

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

The rear planetary ring gear is splined to the out-
put shaft. The front planetary carrier and rear car-
rier ring gear are meshed and rotate as a unit with
the output shaft.
GEARTRAIN OPERATION AND APPLICATION
CHARTS
Operation and application of the first through
fourth and reverse gear elements are outlined in the
function and application charts.
The Component Function Chart (Fig. 7) describes
basic function of various geartrain elements. The
Component Application Chart (Fig. 8) indicates
which elements (including valve body solenoids), are
applied in the various gear ranges.
HYDRAULIC SYSTEM
The hydraulic system consists of the pump, valve
body and solenoids, and four hydraulic accumulators.
The oil pump provides lubrication and operating
pressure.
The valve body controls application of the clutches,
brakes, second coast band, and the converter clutch.
The valve body solenoids control sequencing of the
1-2, 2-3 and 3-4 shift valves. The solenoids are acti-
vated by signals from the transmission control mod-
ule.
The accumulators are used in the clutch and brake
feed circuits to control initial apply pressure. Spring
loaded accumulator pistons modulate the initial
surge of apply pressure for smooth engagement.
OIL PUMP
A gear-type oil pump is used. The pump gears are
mounted in the pump body. The pump drive gear isoperated by the torque converter hub. Drive tangs on
the hub engage in drive slots in the drive gear.
TRANSMISSION VALVE BODY COMPONENTS
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. 9). The various spool valves,
sleeves, plugs and springs are located within the two
body sections.
Fig. 8 Component Application Chart
Fig. 9 Two-Section Transmission Valve Body
JAW-4 AUTOMATIC TRANSMISSION 21 - 169

The manual valve, 1-2 shift valve, primary regula-
tor valve, accumulator control valve, check balls, so-
lenoids and oil strainers are located in the lower
body section (Fig. 10). The remaining control and
shift valves plus check balls and one additional oil
strainer are located in the upper body section (Fig.
11).
Manual Valve
The manual valve is operated by the gearshift link-
age. The valve diverts fluid to the apply circuits ac-
cording to shift lever position.Primary Regulator Valve
The primary regulator valve (Fig. 13) 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 en-
gagement. At light load, the valve decreases line
pressure just enough to maintain smooth engage-
ment.
Fig. 10 Upper Body Components
Fig. 11 Lower Body Components
21 - 170 AW-4 AUTOMATIC TRANSMISSIONJ

PRESSURE TEST ANALYSIS
If pressures in D and Reverse are higher than
specified in test, check for the following:
²throttle cable loose, worn, binding or out of adjust-
ment
²throttle valve, downshift plug, throttle cam, or pri-
mary regulator valve are sticking, worn or damaged
If pressures in D and Reverse are lower than spec-
ified in test, check for following:
²throttle cable loose, worn, binding or out of adjust-
ment
²throttle valve, downshift plug, or throttle cam
sticking, worn or damaged
²primary regulator valve sticking, worn, or dam-
aged
²oil pump gears or housing worn, or damaged
²overdrive clutch worn, or damaged
If pressures are low in D range only, check for fol-
lowing:
²forward clutch worn or damaged
²fluid leakage in D range circuit (component seal
and O-rings)
If pressures are low in Reverse only, check for fol-
lowing:
²shift cable and manual valve out of adjustment
²fluid leakage in reverse circuit (component seal
and O-rings)
²direct clutch worn or damaged
²first/reverse brake worn or damaged
TORQUE CONVERTER STALL TEST
Stall testing checks the holding ability of the trans-
mission clutches and brakes and of the torque con-
verter stator overrunning clutch.Stall speeds are
checked in both Drive and Reverse ranges with
the AW-4 transmission.
(1) Before starting test, be sure fluid level is cor-
rect and fluid is at normal operating temperature.
(2) Connect tachometer to engine. Position tachom-
eter so it can be viewed from drivers seat.
(3) Apply parking brakes and block wheels.
(4) Apply and hold service brakes.
(5) Shift transfer case into 2H position.
(6) Start engine.
WARNING: DO NOT ALLOW ANYONE TO STAND AT
THE FRONT OR REAR OF THE VEHICLE DURING
THE TEST.
(7) Shift transmission into D range.
(8) Open throttle completely and record maximum
engine rpm registered on tachometer. It takes any-
where from 4 to 10 seconds to reach maximum rpm.
However, once maximum rpm has been achieved,do
not hold wide open throttle for more than 3-4
seconds.CAUTION: Stalling the converter causes a rapid in-
crease in fluid temperature. To avoid fluid overheat-
ing, hold wide open throttle for no more than 4
seconds after reaching peak rpm. In addition, if
more than one stall test is required, run the engine
at 1000 rpm with the transmission in Neutral for at
least 20 seconds to cool the fluid.
(9) Stall speed should be in 2100-2400 rpm range
in Drive.
(10) Release throttle, shift transmission into Neu-
tral, and run engine for 20-30 seconds to cool fluid.
(11) Shift transmission into Reverse.
(12) Repeat stall test described in step (8).
(13) Stall speed in Reverse should also be in 2100-
2400 rpm range.
(14) Release accelerator pedal, shift transmission
into Neutral, and run engine for 20-30 seconds to
cool fluid.
STALL SPEED TEST ANALYSIS
If engine rpm is lower than specified in D and Re-
verse, check for the following:
²engine output/performance insufficient
²stator overrunning clutch in torque converter not
holding if engine speed was 1500 rpm or less.
If stall speed in D range is higher than specified,
check for the following:
²line pressure low
²forward clutch slipping
²No. 2 one-way clutch not holding
²overdrive one-way clutch not holding
If stall speed in Reverse was higher than specified,
check for the following:
²line pressure low
²direct clutch slipping
²first/ reverse brake slipping
²overdrive one-way clutch not holding
If stall speeds were higher than specified in both D
and Reverse, check for the following:
²low fluid level
²line pressure low
²overdrive one-way clutch not holding
TIME LAG TEST
This test checks general condition of the overdrive
clutch, forward clutch, rear clutch and first/reverse
brake. Condition is indicated by the amount of time
required for clutch/brake engagement with the en-
gine at curb idle speed. Engagement time is mea-
sured for D and Reverse positions. A stop watch is
recommended for test accuracy.
TEST PROCEDURE
(1) Check and adjust transmission fluid level if
necessary.
(2) Bring transmission to normal operating tem-
perature.
21 - 178 AW-4 TRANSMISSION DIAGNOSISJ

(15) Connect park rod to sector (Fig. 21).
(16) Install park rod bracket (Fig. 26). Tighten
bracket bolts to 10 Nzm (7 ft. lbs.) torque.
(17) Install valve body, oil screen and oil pan. Use
Mopar or Loctite 599 sealer on oil pan seal surface.
(18) Install park/neutral position switch.
ACCUMULATOR PISTONS AND SPRINGS
ACCUMULATOR PISTON AND SPRING
REMOVAL
(1) Remove valve body. Refer to procedure in this
section.(2) Remove accumulator pistons with compressed
air (Fig. 27). Apply air through small feed hole next
to each piston bore. Catch each piston in a shop
towel as it exits bore.
CAUTION: Use only enough air pressure to ease
each piston out of the bore. In addition, remove the
pistons one at a time and tag the pistons and
springs for assembly reference. Do not intermix
them.
(3) Remove and discard piston O-ring seals. Then
clean pistons and springs with solvent.
Fig. 24 Installing Manual Valve Shaft Seals
Fig. 25 Installing Spacer Sleeve On Sector
Fig. 26 Installing Park Rod Bracket
Fig. 27 Accumulator Piston Removal
JAW-4 IN-VEHICLE SERVICE 21 - 189