2002 JEEP GRAND CHEROKEE Air ah

(9) Remove the number 2 bearing from the input
clutch hub.
(10) Remove the overdrive clutch wave snap-ring
from the input clutch retainer.
(11) Remove the UD/OD reaction plate tapered
snap-ring from the input clutch retainer.
(12) Remove the UD/OD reaction plate from the
input clutch retainer.
(13) Remove the UD/OD reaction plate flat snap-
ring from the input clutch retainer (Fig. 70).
(14) Remove the underdrive clutch pack from the
input clutch retainer (Fig. 72).
(15) Using Spring Compressor 8251, compress the
UD/OD balance piston and remove the snap-ring
from the input clutch hub (Fig. 71).
(16) Remove the UD/OD balance piston and piston
return spring from the input clutch retainer (Fig. 72).
(17) Remove the underdrive piston from the input
clutch retainer (Fig. 72).NOTE: Both the UD/OD balance piston and the
underdrive piston have seals molded onto them. If
the seal is damaged, do not attempt to install a new
seal onto the piston. The piston/seal must be
replaced as an assembly.
(18) Remove the input clutch retainer tapered
snap-ring.
(19) Separate input clutch retainer from input
clutch hub.
(20) Separate OD/reverse piston from input clutch
hub retainer (Fig. 72).
(21) Remove all seals and o-rings from the input
shaft and input hub. The o-rings on the input hub
are color coded. Be sure to make note of which o-ring
belongs in which location.
ASSEMBLY
(1) Install all new seals and o-rings onto the input
shaft and input hub. The o-rings on the input hub
are color coded. Be sure to install the correct o-ring
in the correct location.
(2) Check the transmission lubrication check valve
located in the input shaft using shop air. The valve
should only allow air flow in one direction. If the
valve allows no air flow, or air flow in both direc-
tions, the valve will need to be replaced.
(3) Lubricate all seals with MopartATF +4, type
9602, prior to installation.
(4) Assemble the OD/reverse piston onto the input
clutch hub (Fig. 73).
(5) Assemble the input clutch retainer onto the
input clutch hub.
(6) Install the input clutch retainer tapered snap-
ring with tapered side up onto the input clutch hub.
Fig. 71 Compressing UD/OD Balance Piston Using
Tool 8251
1 - PRESS
2 - TOOL 8251
3 - BALANCE PISTON
21 - 238 AUTOMATIC TRANSMISSION - 545RFEWJ
INPUT CLUTCH ASSEMBLY (Continued)

(15) Install the UD/OD reaction plate into the
input clutch retainer. The reaction plate is to be
installed with the big step down.
(16) Install the UD/OD reaction plate upper
tapered snap-ring with tapered side up.
(17) Install the input clutch assembly into Input
Clutch Pressure Fixture 8260 (Fig. 78). Mount a dial
indicator to the assembly, push down on the clutch
discs and zero the indicator against the underdrive
clutch discs (Fig. 79). Apply 20 psi of air pressure to
the underdrive clutch and record the dial indicator
reading. Measure and record UD clutch pack mea-
surement in four (4) places, 90É apart. Take average
of four measurements and compare with UD clutch
pack clearance specification. The correct clutch clear-
ance is 0.84-1.54 mm (0.033-0.061 in.). The reaction
plate is not selective. If the clutch clearance is not
within specification, replace the reaction plate along
with all the friction and steel discs.
(18) Install the overdrive clutch pack into the
input clutch retainer (Fig. 77). The overdrive steel
separator plates can be identified by the lack of the
half-moon cuts in the locating tabs.
(19) Install the overdrive clutch wavy snap-ring
with the two tabbed ears into the input clutch
retainer.
(20) Install the OD/reverse reaction plate into the
input clutch retainer. The reaction plate is non-direc-
tional (Fig. 77).
(21) Install the OD/reverse reaction plate flat
snap-ring into the input clutch retainer.(22) Mount a dial indicator to the assembly and
zero the indicator against the OD/reverse reaction
plate (Fig. 80). Apply 20 psi of air pressure to the
overdrive clutch and record the dial indicator read-
ing. Measure and record OD clutch pack measure-
ment in four (4) places, 90É apart. Take average of
four measurements and compare with OD clutch
pack clearance specification.Verify that the clutch
clearance is 1.103-1.856 mm (0.043-0.073 in.). The
reaction plate is not selective. If the clutch clearance
is not within specification, replace the reaction plate
along with all the friction and steel discs.
Fig. 78 Input Clutch Assembly Mounted on Tool
8260
1 - INPUT CLUTCH ASSEMBLY
2 - TOOL 8260
Fig. 79 Measuring UD Clutch Clearance
1 - TOOL C-3339
2 - UNDERDRIVE CLUTCH PACK
Fig. 80 Measuring OD Clutch Clearance
1 - TOOL C-3339
2 - OD/REV REACTION PLATE
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 243
INPUT CLUTCH ASSEMBLY (Continued)

(23) Install the reverse clutch pack into the input
clutch retainer (Fig. 77).
(24) Install the reverse reaction plate into the
input clutch retainer.
(25) Install the reverse reaction plate selective
snap-ring into the input clutch retainer.
(26) Mount a dial indicator to the assembly, push
down on the clutch discs, pull up on the reaction
plate to ensure the plate is properly seated and zero
the indicator against the reverse clutch discs (Fig.
81). Apply 20 psi of air pressure to the reverse clutch
and record the dial indicator reading. Measure and
record Reverse clutch pack measurement in four (4)
places, 90É apart. Take average of four measurements
and compare with Reverse clutch pack clearance
specification. The correct clutch clearance is 0.58-1.47
mm (0.023-0.058 in.). Adjust as necessary. Install the
chosen snap-ring and re-measure to verify selection.
(27) Remove the reverse clutch pack from the
input clutch retainer.
(28) Install the number 2 bearing onto the under-
drive hub with outer race against the hub with petro-
leum jelly.
(29) Install the underdrive hub into the input
clutch retainer.
(30) Install the number 3 bearing into the over-
drive hub with the outer race against the hub with
petroleum jelly.
(31) Install the overdrive hub into the input clutch
retainer.
(32) Install the number 4 bearing into the reverse
hub with outer race against the hub with petroleum
jelly.(33) Install the reverse hub into the input clutch
retainer.
(34) Install the complete reverse clutch pack.
(35) Install the reverse reaction plate and snap-
ring.
(36) Push up on reaction plate to allow reverse
clutch to move freely.
INPUT SPEED SENSOR
DESCRIPTION
The Input and Output Speed Sensors are two-wire
magnetic pickup devices that generate AC signals as
rotation occurs. They are mounted in the left side of
the transmission case and are considered primary
inputs to the Transmission Control Module (TCM).
OPERATION
The Input Speed Sensor provides information on
how fast the input shaft is rotating. As the teeth of
the input clutch hub pass by the sensor coil, an AC
voltage is generated and sent to the TCM. The TCM
interprets this information as input shaft rpm.
The Output Speed Sensor generates an AC signal
in a similar fashion, though its coil is excited by rota-
tion of the rear planetary carrier lugs. The TCM
interprets this information as output shaft rpm.
The TCM compares the input and output speed
signals to determine the following:
²Transmission gear ratio
²Speed ratio error detection
²CVI calculation
The TCM also compares the input speed signal and
the engine speed signal to determine the following:
²Torque converter clutch slippage
²Torque converter element speed ratio
REMOVAL
(1) Raise vehicle.
(2) Place a suitable fluid catch pan under the
transmission.
(3) Remove the wiring connector from the input
speed sensor (Fig. 82).
(4) Remove the bolt holding the input speed sensor
to the transmission case.
(5) Remove the input speed sensor from the trans-
mission case.
INSTALLATION
(1) Install the input speed sensor into the trans-
mission case.
(2) Install the bolt to hold the input speed sensor
into the transmission case. Tighten the bolt to 11.9
N´m (105 in.lbs.).
Fig. 81 Measuring Reverse Clutch Clearance
1 - TOOL C-3339
2 - REVERSE CLUTCH PACK
21 - 244 AUTOMATIC TRANSMISSION - 545RFEWJ
INPUT CLUTCH ASSEMBLY (Continued)

holding the Belleville spring into the low/reverse
clutch retainer.
(10) Remove the low/reverse clutch Belleville
spring and piston from the low/reverse clutch
retainer. Use 20 psi of air pressure to remove the pis-
ton if necessary.
CLEANING
Clean the overrunning clutch assembly, clutch cam,
and low-reverse clutch retainer. Dry them with com-
pressed air after cleaning.
INSPECTION
Inspect condition of each clutch part after cleaning.
Replace the overrunning clutch roller and spring
assembly if any rollers or springs are worn or dam-
aged, or if the roller cage is distorted, or damaged.
Replace the cam if worn, cracked or damaged.
Replace the low-reverse clutch retainer if the
clutch race, roller surface or inside diameter is
scored, worn or damaged.
ASSEMBLY
(1) Check the bleed orifice to ensure that it is not
plugged or restricted.
(2) Install a new seal on the low/reverse piston.
Lubricate the seal with MopartATF +4, type 9602,
prior to installation.
(3) Install the low/reverse piston into the low/re-
verse clutch retainer.
(4) Position the low/reverse piston Belleville spring
on the low/reverse piston.
(5) Using Spring Compressor 8285 and a suitable
shop press (Fig. 86), compress the low/reverse piston
Belleville spring and install the split retaining ring
to hold the Belleville spring into the low/reverse
clutch retainer.
(6) Install the lower overrunning clutch snap-ring
(Fig. 85).
(7) Assemble the inner and outer races of the over-
running clutch (Fig. 85).
(8) Position the overrunning clutch spacer on the
overrunning clutch.
(9) Install the upper overrunning clutch snap-ring
(Fig. 85).
(10) Assemble and install the low/reverse clutch
pack into the low/reverse clutch retainer (Fig. 84).
(11) Install the low/reverse reaction plate into the
low/reverse clutch retainer (Fig. 84). The reaction
plate is directional and must be installed with the
flat side down.
(12) Install the low/reverse clutch pack snap-ring
(Fig. 84). The snap-ring is selectable and should be
chosen to give the correct clutch pack clearance.
(13) Measure the low/reverse clutch pack clearance
and adjust as necessary. The correct clutch clearance
is 1.00-1.74 mm (0.039-0.075 in.).
(14) Install the overrunning clutch into the low/re-
verse clutch retainer making sure that the index
splines are aligned with the retainer.
(15) Install the overrunning clutch inner snap-
ring.
Fig. 85 Overrunning Clutch
1 - SNAP-RING
2 - OUTER RACE
3 - OVERRUNNING CLUTCH
4 - SPACER
Fig. 86 Compress Low/Reverse Belleville Spring
Using Tool 8285
1 - PRESS
2 - TOOL 8285
3 - BELLEVILLE SPRING
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 247
LOW/REVERSE CLUTCH (Continued)

(9) Remove the oil pump valve retainers and asso-
ciated valve and spring one at a time (Fig. 93) (Fig.
94). Mark the combination of components as a group
and tag them as to the location from which they were
removed.
CLEANING
Clean pump and support components with solvent
and dry them with compressed air.
INSPECTION
Check condition of the seal rings and thrust
washer on the reaction shaft support. The seal rings
do not need to be replaced unless cracked, broken, or
severely worn.
Inspect the pump and support components. Replace
the pump or support if the seal ring grooves or
machined surfaces are worn, scored, pitted, or dam-
aged. Replace the pump gears if pitted, worn
chipped, or damaged.Inspect the pump reaction shaft support bushings.
Replace either bushing only if heavily worn, scored or
damaged. It is not necessary to replace the bushings
unless they are actually damaged.
Inspect the valves and plugs for scratches, burrs,
nicks, or scores. Minor surface scratches on steel
valves and plugs can be removed with crocus cloth
butdo not round off the edges of the valve or
plug lands.Maintaining sharpness of these edges is
vitally important. The edges prevent foreign matter
from lodging between the valves and plugs and the
bore.
Inspect all the valve and plug bores in the oil
pump cover. Use a penlight to view the bore interi-
ors. Replace the oil pump if any bores are distorted
or scored. Inspect all of the valve 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.
Fig. 93 Oil Pump Valve Body
1 - T/C REGULATOR VALVE
2 - T/C LIMIT VALVE
3 - REGULATOR VALVE
4 - OIL PUMP VALVE BODY
Fig. 94 T/C Switch Valve
1 - RETAINER
2 - T/C SWITCH VALVE
3 - OIL PUMP VALVE BODY
21 - 252 AUTOMATIC TRANSMISSION - 545RFEWJ
OIL PUMP (Continued)

OPERATION
REACTION PLANETARY GEARTRAIN
The reaction planetary carrier and reverse sun
gear of the reaction planetary geartrain are a single
component which is held by the 2C clutch when
required. The reaction annulus gear is a stand alone
component that can be driven by the reverse clutch
or held by the 4C clutch. The reaction sun gear is
driven by the overdrive clutch.
REVERSE PLANETARY GEARTRAIN
The reverse planetary geartrain is the middle of
the three planetary sets. The reverse planetary car-
rier can be driven by the overdrive clutch as
required. The reverse planetary carrier is also
splined to the input annulus gear, which can be held
by the low/reverse clutch. The reverse planetary
annulus, input planetary carrier, and output shaft
are all one piece.
INPUT PLANETARY GEARTRAIN
The input sun gear of the input planetary
geartrain is driven by the underdrive clutch.
DISASSEMBLY
(1) Remove the snap-ring holding the input annu-
lus into the input carrier (Fig. 104).
(2) Remove the input annulus from the input car-
rier (Fig. 104).
(3) Remove the number 9 bearing from the reverse
planetary carrier. Note that this planetary carrier
has four pinion gears.
(4) Remove the reverse planetary gear carrier (Fig.
104).
(5) Remove the number 10 bearing from the input
sun gear (Fig. 104).
(6) Remove the input sun gear from the input car-
rier (Fig. 104).
(7) Remove the number 11 bearing from the input
carrier (Fig. 104).
CLEANING
Clean the planetary components in solvent and dry
them with compressed air.
INSPECTION
Check sun gear and driving shell condition.
Replace the gear if damaged or if the bushings are
scored or worn. The bushings are not serviceable.
Fig. 104 Reverse/Input Planetary Carrier Assembly
1 - SNAP-RING 5 - INPUT PLANETARY CARRIER
2 - BEARING NUMBER 10 6 - INPUT SUN GEAR
3 - BEARING NUMBER 11 7 - REVERSE PLANETARY CARRIER
4 - INPUT ANNULUS
21 - 260 AUTOMATIC TRANSMISSION - 545RFEWJ
PLANETARY GEARTRAIN (Continued)

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.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 109) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The con-
verter clutch engages in third gear. The torque con-
verter hub drives the transmission oil (fluid) pump
and contains an o-ring seal to better control oil flow.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid. If the fluid
is contaminated, flush the fluid cooler and lines.
Fig. 109 Torque Converter Assembly
1 - TURBINE ASSEMBLY
2-STATOR
3 - CONVERTER HUB
4 - O-RING
5 - IMPELLER ASSEMBLY
6 - CONVERTER CLUTCH PISTON
7 - TURBINE HUB
21 - 264 AUTOMATIC TRANSMISSION - 545RFEWJ
SOLENOIDS (Continued)

CLEANING
Clean the valve housings, valves, plugs, springs,
and separator plates with a standard parts cleaning
solution only. Do not use gasoline, kerosene, or any
type of caustic solution. (Fig. 131)
Do not immerse any of the electrical components in
cleaning solution. Clean the electrical components by
wiping them off with dry shop towels only.
Dry all except the electrical parts with compressed
air. Make sure all passages are clean and free from
obstructions.Do not use rags or shop towels to
dry or wipe off valve body components. Lint
from these materials can stick to valve body
parts, interfere with valve operation, and clog
filters and fluid passages.
INSPECTION
Inspect all of the valve body mating surfaces for
scratches, nicks, burrs, or distortion. Use a straight-edge to check surface flatness. Minor scratches may
be removed with crocus cloth using only very light
pressure.
Minor distortion of a valve body mating surface
may be corrected by smoothing the surface with a
sheet of crocus cloth. Position the crocus cloth on a
surface plate, sheet of plate glass or equally flat sur-
face. If distortion is severe or any surfaces are
heavily scored, the valve body will have to be
replaced.
Inspect the valves and plugs (Fig. 132) for
scratches, burrs, nicks, or scores. Minor surface
scratches on steel valves and plugs can be removed
with crocus cloth butdo not round off the edges
of the valve or plug lands.Maintaining sharpness
of these edges is vitally important. The edges prevent
foreign matter from lodging between the valves and
plugs and the bore.
Fig. 130 Valve Body Components
1 - SOLENOID SWITCH VALVE
2 - MANUAL VALVE
3 - LOW REVERSE SWITCH VALVE
4 - LOW REVERSE ACCUMULATOR
5 - 2ND CLUTCH ACCUMULATOR
6 - UNDERDRIVE ACCUMULATOR
7 - OVERDRIVE ACCUMULATOR
8 - 4TH CLUTCH ACCUMULATOR
9 - CHECK BALLS (7)
Fig. 131 Valve Body Components
1 - SOLENOID SWITCH VALVE
2 - MANUAL VALVE
3 - LOW REVERSE SWITCH VALVE
4 - LOW REVERSE ACCUMULATOR
5 - 2ND CLUTCH ACCUMULATOR
6 - UNDERDRIVE ACCUMULATOR
7 - OVERDRIVE ACCUMULATOR
8 - 4TH CLUTCH ACCUMULATOR
9 - CHECK BALLS (7)
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 277
VALVE BODY (Continued)