2002 JEEP GRAND CHEROKEE Gear oil

A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
SPEED SENSOR
DESCRIPTION
The speed sensor (Fig. 240) is located in the over-
drive gear case. The sensor is positioned over the
park gear and monitors transmission output shaft
rotating speed.
OPERATION
Speed sensor signals are triggered by the park
gear lugs as they rotate past the sensor pickup face.
Input signals from the sensor are sent to the trans-
mission control module for processing. Signals from
this sensor are shared with the powertrain control
module.
THROTTLE VALVE CABLE
DESCRIPTION
Transmission throttle valve cable adjustment is
extremely important to proper operation. This adjust-
ment positions the throttle valve, which controls shift
speed, quality, and part-throttle downshift sensitivity.
If cable setting is too loose, early shifts and slip-
page between shifts may occur. If the setting is too
tight, shifts may be delayed and part throttle down-
shifts may be very sensitive.
The transmission throttle valve is operated by a
cam on the throttle lever. The throttle lever is oper-
ated by an adjustable cable (Fig. 241). The cable is
attached to an arm mounted on the throttle lever
shaft. A retaining clip at the engine-end of the cable
is removed to provide for cable adjustment. The
retaining clip is then installed back onto the throttle
valve cable to lock in the adjustment.
ADJUSTMENTS - TRANSMISSION THROTTLE
VALVE CABLE
A correctly adjusted throttle valve cable (Fig. 242)
will cause the throttle lever on the transmission to
move simultaneously with the throttle body lever
from the idle position. Proper adjustment will allow
Fig. 240 Transmission Output Speed Sensor
1 - TRANSMISSION OUTPUT SHAFT SPEED SENSOR
2 - SEAL
Fig. 241 Throttle Valve Cable
1 - THROTTLE VALVE CABLE
2 - THROTTLE VALVE LEVER
3 - THROTTLE BODY
21 - 126 AUTOMATIC TRANSMISSION - 42REWJ
SOLENOID (Continued)

TORQUE CONVERTER CLUTCH (TCC)
The torque converter clutch is hydraulically
applied and is released when fluid is vented from the
hydraulic circuit by the torque converter control
(TCC) solenoid on the valve body. The torque con-
verter clutch is controlled by the Powertrain Control
Module (PCM). The torque converter clutch engages
in fourth gear, and in third gear under various con-
ditions, such as when the O/D switch is OFF, when
the vehicle is cruising on a level surface after the
vehicle has warmed up. The torque converter clutch
will disengage momentarily when an increase in
engine load is sensed by the PCM, such as when the
vehicle begins to go uphill or the throttle pressure is
increased.
REMOVAL
(1) Remove transmission and torque converter
from vehicle.
(2) Place a suitable drain pan under the converter
housing end of the transmission.
CAUTION: Verify that transmission is secure on the
lifting device or work surface, the center of gravity
of the transmission will shift when the torque con-
verter is removed creating an unstable condition.
The torque converter is a heavy unit. Use caution
when separating the torque converter from the
transmission.
(3) Pull the torque converter forward until the cen-
ter hub clears the oil pump seal.
(4) Separate the torque converter from the trans-
mission.
INSTALLATION
Check converter hub and drive notches for sharp
edges, burrs, scratches, or nicks. Polish the hub and
notches with 320/400 grit paper or crocus cloth if nec-
essary. The hub must be smooth to avoid damaging
the pump seal at installation.
(1) Lubricate oil pump seal lip with transmission
fluid.
(2) Place torque converter in position on transmis-
sion.
CAUTION: Do not damage oil pump seal or bushing
while inserting torque converter into the front of the
transmission.
(3) Align torque converter to oil pump seal open-
ing.
(4) Insert torque converter hub into oil pump.
(5) While pushing torque converter inward, rotate
converter until converter is fully seated in the oil
pump gears.
(6) Check converter seating with a scale and
straightedge (Fig. 253). Surface of converter lugs
should be 1/2 in. to rear of straightedge when con-
verter is fully seated.
(7) If necessary, temporarily secure converter with
C-clamp attached to the converter housing.
(8) Install the transmission in the vehicle.
(9) Fill the transmission with the recommended
fluid.
Fig. 252 Stator Operation
1 - DIRECTION STATOR WILL FREE WHEEL DUE TO OIL
PUSHING ON BACKSIDE OF VANES
2 - FRONT OF ENGINE
3 - INCREASED ANGLE AS OIL STRIKES VANES
4 - DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING
AGAINST STATOR VANES
Fig. 253 Checking Torque Converter Seating -
Typical
1 - SCALE
2 - STRAIGHTEDGE
WJAUTOMATIC TRANSMISSION - 42RE 21 - 133
TORQUE CONVERTER (Continued)

REGULATOR VALVE
The pressure regulator valve is needed to control
the hydraulic pressure within the system and reduce
the amount of heat produced in the fluid. The pres-
sure regulator valve is located in the valve body near
the manual valve. The pressure regulator valve train
controls the maximum pressure in the lines by
metering the dumping of fluid back into the sump.
Regulated pressure is referred to as ªline pressure.º
The regulator valve (Fig. 259) has a spring on one
end that pushes the valve to the left. This closes a
dump (vent) that is used to lower pressure. The clos-
ing of the dump will cause the oil pressure to
increase. Oil pressure on the opposite end of thevalve pushes the valve to the right, opening the
dump and lowering oil pressure. The result is spring
pressure working against oil pressure to maintain
the oil at specific pressures. With the engine run-
ning, fluid flows from the pump to the pressure reg-
ulator valve, manual valve, and the interconnected
circuits. As fluid is sent through passages to the reg-
ulator valve, the pressure pushes the valve to the
right against the large spring. It is also sent to the
reaction areas on the left side of the throttle pressure
plug and the line pressure plug. With the gear selec-
tor in the PARK position, fluid recirculates through
the regulator and manual valves back to the sump.
Fig. 259 Regulator Valve in PARK Position
21 - 140 AUTOMATIC TRANSMISSION - 42REWJ
VALVE BODY (Continued)

BOOST VALVE
The boost valve (Fig. 277) provides increased fluid
apply pressure to the overdrive clutch during 3-4
upshifts (Fig. 278), and when accelerating in fourth
gear. The boost valve also serves to increase line
pressure during torque converter lock-up.
REMOVAL
The valve body can be removed for service without
having to remove the transmission assembly.
The valve body can be disassembled for cleaning
and inspection of the individual components.
The only replaceable valve body components are:
²Manual lever.
²Manual lever washer, seal, E-clip, and shaft
seal.
²Manual lever detent ball.
²Throttle lever.
²Fluid filter.
²Pressure adjusting screw bracket.
²Governor pressure solenoid.
²Governor pressure sensor (includes transmission
temperature thermistor).
²Converter clutch/overdrive solenoid assembly
and harness.
²Governor housing gasket.
²Solenoid case connector O-rings.
(1) Shift transmission into NEUTRAL.
(2) Raise vehicle.
(3) Remove gearshift and throttle levers from shaft
of valve body manual lever.
(4) Disconnect wires at solenoid case connector
(Fig. 279).
(5) Position drain pan under transmission oil pan.
(6) Remove transmission oil pan and gasket.
(7) Remove fluid filter from valve body.
(8) Remove bolts attaching valve body to transmis-
sion case.
(9) Lower valve body enough to remove accumula-
tor piston and springs.
(10) Work manual lever shaft and electrical con-
nector out of transmission case.
(11) Lower valve body, rotate valve body away
from case, pull park rod out of sprag, and remove
valve body (Fig. 280).
Fig. 277 Boost Valve Before Lock-up
Fig. 278 Boost Valve After Lock-up
Fig. 279 Transmission Case Connector
1 - SOLENOID CASE CONNECTOR
2 - PARK/NEUTRAL POSITION SWITCH
21 - 154 AUTOMATIC TRANSMISSION - 42REWJ
VALVE BODY (Continued)

GOVERNOR BODY, SENSOR AND SOLENOID
(1) Turn valve body assembly over so accumulator
side of transfer plate is facing down.
(2) Install new O-rings on governor pressure sole-
noid and sensor.
(3) Lubricate solenoid and sensor O-rings with
clean transmission fluid.
(4) Install governor pressure sensor in governor
body.
(5) Install governor pressure solenoid in governor
body. Push solenoid in until it snaps into place in
body.
(6) Position governor body gasket on transfer
plate.
(7) Install retainer plate on governor body and
around solenoid. Be sure solenoid connector is posi-
tioned in retainer cutout.
(8) Align screw holes in governor body and trans-
fer plate. Then install and tighten governor body
screws to 4 N´m (35 in. lbs.) torque.
(9) Connect harness wires to governor pressure
solenoid and governor pressure sensor.
(10) Install fluid filter and pan.
(11) Lower vehicle.
(12) Fill transmission with recommended fluid and
road test vehicle to verify repair.
INSTALLATION
(1) Check condition of O-ring seals on valve body
harness connector (Fig. 330). Replace seals on con-
nector body if cut or worn.
(2) Check condition of manual lever shaft seal in
transmission case. Replace seal if lip is cut or worn.
Install new seal with 15/16 deep well socket (Fig.
331).
(3) Check condition of seals on accumulator piston
(Fig. 332). Install new piston seals, if necessary.
(4) Place valve body manual lever in low (1 posi-
tion) so ball on park lock rod will be easier to install
in sprag.
(5) Lubricate shaft of manual lever with petroleum
jelly. This will ease inserting shaft through seal in
case.
(6) Lubricate seal rings on valve body harness con-
nector with petroleum jelly.
(7) Position valve body in case and work end of
park lock rod into and through pawl sprag. Turn pro-
peller shaft to align sprag and park lock teeth if nec-
essary. The rod will click as it enters pawl. Move rod
to check engagement.
CAUTION: It is possible for the park rod to displace
into a cavity just above the pawl sprag during
installation. Make sure the rod is actually engaged
in the pawl and has not displaced into this cavity.(8) Install accumulator springs and piston into
case. Then swing valve body over piston and outer
spring to hold it in place.
(9) Align accumulator piston and outer spring,
manual lever shaft and electrical connector in case.
(10) Then seat valve body in case and install one
or two bolts to hold valve body in place.
(11) Tighten valve body bolts alternately and
evenly to 11 N´m (100 in. lbs.) torque.
(12) Install new fluid filter on valve body. Tighten
filter screws to 4 N´m (35 in. lbs.) torque.
(13) Install throttle and gearshift levers on valve
body manual lever shaft.
(14) Check and adjust front and rear bands if nec-
essary.
(15) Connect solenoid case connector wires.
(16) Install oil pan and new gasket. Tighten pan
bolts to 13.6 N´m (125 in. lbs.) torque.
(17) Lower vehicle and fill transmission with
MopartATF +4, type 9602, fluid.
(18) Check and adjust gearshift and throttle valve
cables, if necessary.
ADJUSTMENTS - VALVE BODY
CONTROL PRESSURE ADJUSTMENTS
There are two control pressure adjustments on the
valve body;
²Line Pressure
²Throttle Pressure
Line and throttle pressures are interdependent
because each affects shift quality and timing. As a
result, both adjustments must be performed properly
and in the correct sequence. Adjust line pressure first
and throttle pressure last.
Fig. 330 Valve Body Harness Connector O-Ring Seal
1 - CONNECTOR O-RINGS
2 - VALVE BODY HARNESS CONNECTOR
3 - HARNESS
WJAUTOMATIC TRANSMISSION - 42RE 21 - 175
VALVE BODY (Continued)

AUTOMATIC TRANSMISSION - 545RFE
TABLE OF CONTENTS
page page
AUTOMATIC TRANSMISSION - 545RFE
DESCRIPTION........................178
OPERATION..........................179
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION.....................179
DIAGNOSIS AND TESTING - PRELIMINARY . 180
DIAGNOSIS AND TESTING - ROAD
TESTING...........................180
DIAGNOSIS AND TESTING - HYDRAULIC
PRESSURE TEST....................181
DIAGNOSIS AND TESTING - AIR CHECKING
TRANSMISSION CLUTCH OPERATION....182
DIAGNOSIS AND TESTING - CONVERTER
HOUSING FLUID LEAK................182
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR.....................183
REMOVAL............................183
DISASSEMBLY........................185
CLEANING...........................190
INSPECTION.........................190
ASSEMBLY...........................190
INSTALLATION........................197
SCHEMATICS AND DIAGRAMS
HYDRAULIC SCHEMATICS.............199
SPECIFICATIONS
TRANSMISSION.....................220
SPECIAL TOOLS
RFE TRANSMISSION.................221
4C RETAINER/BULKHEAD
DISASSEMBLY........................224
ASSEMBLY...........................224
ADAPTER HOUSING SEAL
REMOVAL............................225
INSTALLATION........................225
BRAKE TRANSMISSION SHIFT INTERLOCK
MECHANISM
DESCRIPTION........................226
OPERATION..........................226
DIAGNOSIS AND TESTING - BRAKE
TRANSMISSION SHIFT INTERLOCK......226
ADJUSTMENTS - BRAKE TRANSMISSION
SHIFT INTERLOCK...................227
FLUID AND FILTER
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL.............228
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID.......................228DIAGNOSIS AND TESTING - FLUID
CONTAMINATION....................228
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK............................229
STANDARD PROCEDURE - FLUID AND
FILTER REPLACEMENT...............230
STANDARD PROCEDURE - TRANSMISSION
FILL...............................230
GEARSHIFT CABLE
DIAGNOSIS AND TESTING - GEARSHIFT
CABLE.............................231
REMOVAL............................231
INSTALLATION........................231
ADJUSTMENTS - GEARSHIFT CABLE......232
HOLDING CLUTCHES
DESCRIPTION........................233
OPERATION..........................234
INPUT CLUTCH ASSEMBLY
DESCRIPTION........................235
OPERATION..........................235
DISASSEMBLY........................237
ASSEMBLY...........................238
INPUT SPEED SENSOR
DESCRIPTION........................244
OPERATION..........................244
REMOVAL............................244
INSTALLATION........................244
LINE PRESSURE (LP) SENSOR
DESCRIPTION........................245
OPERATION..........................245
REMOVAL............................245
INSTALLATION........................245
LOW/REVERSE CLUTCH
DISASSEMBLY........................246
CLEANING...........................247
INSPECTION.........................247
ASSEMBLY...........................247
OIL PUMP
DESCRIPTION........................248
OPERATION..........................248
STANDARD PROCEDURE - OIL PUMP
VOLUME CHECK.....................249
DISASSEMBLY........................250
CLEANING...........................252
INSPECTION.........................252
ASSEMBLY...........................253
OIL PUMP FRONT SEAL
REMOVAL............................253
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 177

INSTALLATION........................253
OUTPUT SPEED SENSOR
DESCRIPTION........................254
OPERATION..........................254
REMOVAL............................254
INSTALLATION........................254
OVERDRIVE SWITCH
DESCRIPTION........................254
OPERATION..........................254
PARK LOCK CABLE
REMOVAL............................255
INSTALLATION........................255
PISTONS
DESCRIPTION........................256
OPERATION..........................256
PLANETARY GEARTRAIN
DESCRIPTION........................258
OPERATION..........................260
DISASSEMBLY........................260
CLEANING...........................260
INSPECTION.........................260
ASSEMBLY...........................261
SHIFT MECHANISM
DESCRIPTION........................261
OPERATION..........................261
REMOVAL............................261
INSTALLATION........................263
SOLENOID SWITCH VALVE
DESCRIPTION........................263
OPERATION..........................263
SOLENOIDS
DESCRIPTION........................263OPERATION..........................264
TORQUE CONVERTER
DESCRIPTION........................264
OPERATION..........................268
REMOVAL............................269
INSTALLATION........................269
TRANSMISSION CONTROL RELAY
DESCRIPTION........................270
OPERATION..........................270
TRANSMISSION RANGE SENSOR
DESCRIPTION........................270
OPERATION..........................270
TRANSMISSION SOLENOID/TRS ASSEMBLY
DESCRIPTION........................271
OPERATION..........................271
REMOVAL............................272
INSTALLATION........................272
TRANSMISSION TEMPERATURE SENSOR
DESCRIPTION........................272
OPERATION..........................272
VALVE BODY
DESCRIPTION........................273
OPERATION..........................273
REMOVAL............................274
DISASSEMBLY........................275
CLEANING...........................277
INSPECTION.........................277
ASSEMBLY...........................278
INSTALLATION........................279
AUTOMATIC TRANSMISSION -
545RFE
DESCRIPTION
The 545RFE automatic transmission is a sophisti-
cated, multi-range, electronically controlled transmis-
sion which combines optimized gear ratios for
responsive performance, state of the art efficiency
features and low NVH. Other features include driver
adaptive shifting and three planetary gear sets to
provide wide ratio capability with precise ratio steps
for optimum driveability. The three planetary gear
sets also make available a unique alternate second
gear ratio. The primary 2nd gear ratio fits between
1st and 3rd gears for normal through-gear accelera-
tions. The alternate second gear ratio (2prime) allows
smoother 4-2 kickdowns at high speeds to provide
2nd gear passing performance over a wider highway
cruising range. An additional overdrive ratio (0.67:1)
is also provided for greater fuel economy and less
NVH at highway speeds.The hydraulic portion of the transmission consists
of the transmission fluid, fluid passages, hydraulic
valves, and various line pressure control components.
The primary mechanical components of the trans-
mission consist of the following:
²Three multiple disc input clutches
²Three multiple disc holding clutches
²Five hydraulic accumulators
²Three planetary gear sets
²Dual Stage Hydraulic oil pump
²Valve body
²Solenoid pack
The TCM is the ªheartº or ªbrainº of the electronic
control system and relies on information from vari-
ous direct and indirect inputs (sensors, switches, etc.)
to determine driver demand and vehicle operating
conditions. With this information, the TCM can cal-
culate and perform timely and quality shifts through
various output or control devices (solenoid pack,
transmission control relay, etc.).
21 - 178 AUTOMATIC TRANSMISSION - 545RFEWJ

TRANSMISSION IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan
sealing surface (Fig. 1). Refer to this information
when ordering replacement parts. A label is attached
to the transmission case above the stamped numbers.
The label gives additional information which may
also be necessary for identification purposes.
GEAR RATIOS The 545RFE gear ratios are:
1st .................................3.00:1
2nd.................................1.67:1
2nd Prime............................1.50:1
3rd .................................1.00:1
4th .................................0.75:1
5th .................................0.67:1
Reverse..............................3.00:1
OPERATION
The 545RFE offers full electronic control of all auto-
matic up and downshifts, and features real-time adap-
tive closed-loop shift and pressure control. Electronic
shift and torque converter clutch controls help protect
the transmission from damage due to high tempera-
tures, which can occur under severe operating condi-
tions. By altering shift schedules, line pressure, and
converter clutch control, these controls reduce heat gen-
eration and increase transmission cooling.
To help reduce efficiency-robbing parasitic losses,
the transmission includes a dual-stage transmission
fluid pump with electronic output pressure control.
Under most driving conditions, pump output pres-
sure greatly exceeds that which is needed to keep the
clutches applied. The 545RFE pump-pressure controlsystem monitors input torque and adjusts the pump
pressure accordingly. The primary stage of the pump
works continuously; the second stage is bypassed
when demand is low. The control system also moni-
tors input and output speed and, if incipient clutch
slip is observed, the pressure control solenoid duty
cycle is varied, increasing pressure in proportion to
demand.
A high-travel torque converter damper assembly
allows earlier torque converter clutch engagement to
reduce slippage. Needle-type thrust bearings reduce
internal friction. The 545RFE is packaged in a one-
piece die-cast aluminum case. To reduce NVH, the
case has high lateral, vertical and torsional stiffness.
It is also designed to maximize the benefit of the
structural dust cover that connects the bottom of the
bell housing to the engine bedplate, enhancing over-
all power train stiffness. Dual filters protect the
pump and other components. A pump return filter is
added to the customary main sump filter. Indepen-
dent lubrication and cooler circuits assure ample
pressure for normal transmission operation even if
the cooler is obstructed or the fluid cannot flow due
to extremely low temperatures.
The hydraulic control system design (without elec-
tronic assist) provides the transmission with PARK,
REVERSE, NEUTRAL, SECOND, and THIRD gears,
based solely on driver shift lever selection. This
design allows the vehicle to be driven (in ªlimp-inº
mode) in the event of a electronic control system fail-
ure, or a situation that the Transmission Control
Module (TCM) recognizes as potentially damaging to
the transmission.
The TCM also performs certain self-diagnostic
functions and provides comprehensive information
(sensor data, DTC's, etc.) which is helpful in proper
diagnosis and repair. This information can be viewed
with the DRB scan tool.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION
CAUTION: Before attempting any repair on a
545RFE automatic transmission, check for Diagnos-
tic Trouble Codes with the DRBTscan tool.
Transmission malfunctions may be caused by these
general conditions:
²Poor engine performance
²Improper adjustments
²Hydraulic malfunctions
²Mechanical malfunctions
²Electronic malfunctions
Fig. 1 Transmission Part And Serial Number
Location
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 179
AUTOMATIC TRANSMISSION - 545RFE (Continued)