Transfer switch JEEP GRAND CHEROKEE 2003 WJ / 2.G Owner's Guide

OPERATION
The converter impeller (Fig. 115) (driving member),
which is integral to the converter housing and bolted
to the engine drive plate, rotates at engine speed.
The converter turbine (driven member), which reacts
from fluid pressure generated by the impeller, rotates
and turns the transmission input shaft.
TURBINE
As the fluid that was put into motion by the impel-
ler blades strikes the blades of the turbine, some of
the energy and rotational force is transferred into the
turbine and the input shaft. This causes both of them
(turbine and input shaft) to rotate in a clockwise
direction following the impeller. As the fluid is leav-
ing the trailing edges of the turbine's blades it con-
tinues in a ªhinderingº direction back toward the
impeller. If the fluid is not redirected before it strikes
the impeller, it will strike the impeller in such a
direction that it would tend to slow it down.
STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft (Fig. 116).
Under stall conditions (the turbine is stationary), the
oil leaving the turbine blades strikes the face of the
stator blades and tries to rotate them in a counter-
clockwise direction. When this happens the over-run-ning clutch of the stator locks and holds the stator
from rotating. With the stator locked, the oil strikes
the stator blades and is redirected into a ªhelpingº
direction before it enters the impeller. This circula-
tion of oil from impeller to turbine, turbine to stator,
and stator to impeller, can produce a maximum
torque multiplication of about 2.4:1. As the turbine
begins to match the speed of the impeller, the fluid
that was hitting the stator in such as way as to
cause it to lock-up is no longer doing so. In this con-
dition of operation, the stator begins to free wheel
and the converter acts as a fluid coupling.
TORQUE CONVERTER CLUTCH (TCC)
In a standard torque converter, the impeller and
turbine are rotating at about the same speed and the
stator is freewheeling, providing no torque multipli-
cation. By applying the turbine's piston and friction
material to the front cover, a total converter engage-
ment can be obtained. The result of this engagement
is a direct 1:1 mechanical link between the engine
and the transmission.
The clutch can be engaged in second, third, fourth,
and fifth gear ranges depending on overdrive control
switch position. If the overdrive control switch is in
the normal ON position, the clutch will engage after
the shift to fourth gear, and above approximately 72
km/h (45 mph). If the control switch is in the OFF
Fig. 115 Torque Converter Fluid Operation - Typical
1 - APPLY PRESSURE 3 - RELEASE PRESSURE
2 - THE PISTON MOVES SLIGHTLY FORWARD 4 - THE PISTON MOVES SLIGHTLY REARWARD
21 - 268 AUTOMATIC TRANSMISSION - 545RFEWJ
TORQUE CONVERTER (Continued)

VALVE BODY
DESCRIPTION
The valve body consists of a cast aluminum valve
body, a separator plate, and a transfer plate. The
valve body contains valves and check balls that con-
trol fluid delivery to the torque converter clutch,
bands, and frictional clutches. The valve body con-
tains the following components (Fig. 121) and (Fig.
122):
²Solenoid switch valve
²Manual valve
²Low/reverse switch valve
²5 Accumulators
²7 check balls
OPERATION
NOTE: Refer to the Hydraulic Schematics for a
visual aid in determining valve location, operation
and design.
SOLENOID SWITCH VALVE
The Solenoid Switch Valve (SSV) controls the direc-
tion of the transmission fluid when the L/R-TCC sole-
noid is energized.
The Solenoid Switch Valve controls line pressure
from the LR-TCC solenoid. In 1st gear, the SSV will
Fig. 121 Valve Body Components
1 - LOW/REVERSE ACCUMULATOR 6 - OVERDRIVE ACCUMULATOR
2 - LOW/REVERSE SWITCH VALVE 7 - UNDERDRIVE ACCUMULATOR
3 - UPPER VALVE BODY 8 - 4C ACCUMULATOR
4 - MANUAL VALVE 9 - 2C ACCUMULATOR
5 - SOLENOID SWITCH VALVE
Fig. 122 Check Ball Locations
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 273

(7) Remove the screws holding the accumulator
cover onto the valve body (Fig. 128).
(8) Remove the accumulator springs and pistons
from the valve body. Note which accumulator piston
and spring belong in each location.
(9) Place the valve body on the bench with the
transfer plate upward.
NOTE: The valve body contains seven check balls.
The transfer plate must be placed upward to pre-
vent losing the check balls when the transfer plate
is removed from the valve body.
(10) Remove the screws holding the valve body to
the valve body transfer plate.
(11) Remove the transfer plate from the valve
body. Note the location of all check balls (Fig. 129).
(12) Remove the check balls from the valve body.
(13) Remove the retainers securing the solenoid
switch valve, manual valve, and the low/reverse
switch valve into the valve body and remove the
associated valve and spring. Tag each valve andspring combination with location information to aid
in assembly. (Fig. 130)
Fig. 128 Valve Body Components
1 - LOW/REVERSE ACCUMULATOR 6 - OVERDRIVE ACCUMULATOR
2 - LOW/REVERSE SWITCH VALVE 7 - UNDERDRIVE ACCUMULATOR
3 - UPPER VALVE BODY 8 - 4C ACCUMULATOR
4 - MANUAL VALVE 9 - 2C ACCUMULATOR
5 - SOLENOID SWITCH VALVE
Fig. 129 Check Ball Locations
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VALVE BODY (Continued)

Inspect all the valve and plug bores in the valve
body. Use a penlight to view the bore interiors.
Replace 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
inspection. It should not be necessary to replace a
valve body assembly unless it is damaged in han-
dling.
Inspect all the accumulator bores in the valve body.
Use a penlight to view the bore interiors. Replace the
valve body if any bores are distorted or scored.Inspect all of the accumulator springs. The springs
must be free of distortion, warpage or broken coils.
Inspect all the fluid seals on the valve body (Fig.
133). Replace any seals that are cracked, distorted, or
damaged in any way. These seals pass fluid pressure
directly to the clutches. Any pressure leak at these
points, may cause transmission performance prob-
lems.
ASSEMBLY
(1) Lubricate valves, springs, and the housing
valve bores with clean transmission fluid.
(2) Install solenoid switch valve, manual valve,
and the low/reverse switch valve into the valve body.
(3) Install the retainers to hold each valve into the
valve body.
(4) Install the valve body check balls into their
proper locations.
(5) Position the transfer plate onto the valve body.
(6) Install the screws to hold the transfer plate to
the valve body. Tighten the screws to 5.6 N´m (50 in.
lbs.).
(7) Install the accumulator pistons and springs
into the valve body in the location from which they
were removed. Note that all accumulators except the
overdrive have two springs. The overdrive accumula-
tor piston has only one spring.
Fig. 132 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. 133 Valve Body Seals
1 - UNDERDRIVE ACCUMULATOR (2 SPRINGS)
2 - 4TH CLUTCH ACCUMULATOR (2 SPRINGS)
3 - 2ND CLUTCH ACCUMULATOR (2 SPRINGS)
4 - LOW REVERSE ACCUMULATOR (2 SPRINGS)
5 - LOW/REVERSE PASSAGE SEAL
6 - 2ND CLUTCH PASSAGE SEAL
7 - 4TH CLUTCH PASSAGE SEAL
8 - OVERDRIVE ACCUMULATOR (1 SPRING)
21 - 278 AUTOMATIC TRANSMISSION - 545RFEWJ
VALVE BODY (Continued)

(8) Position the accumulator cover onto the valve
body.
(9) Install the screws to hold the accumulator
cover onto the valve body. Tighten the screws to 4.5
N´m (40 in. lbs.).
(10) Install the TRS selector plate onto the valve
body and the manual valve.
(11) Install the solenoid and pressure switch
assembly onto the valve body.
(12) Install the screws to hold the solenoid and
pressure switch assembly onto the valve body.
Tighten the screws to 5.7 N´m (50 in. lbs.). Tighten
the screws adjacent to the arrows cast into the bot-
tom of the transfer plate first.
(13) Position the detent spring onto the valve body.
(14) Install the screw to hold the detent spring
onto the valve body. Tighten the screw to 4.5 N´m (40
in. lbs.).
(15) Install new clutch passage seals onto the
valve body, if necessary
INSTALLATION
(1) Check condition of seals on valve body and the
solenoid and pressure switch assembly. Replace seals
if cut or worn.
(2) Place TRS selector plate in the PARK position.
(3) Place the transmission in the PARK position.
(4) Lubricate seal on the solenoid and pressure
switch assembly connector with petroleum jelly.(5) Position valve body in transmission and align
the manual lever on the valve body to the pin on the
transmission manual shift lever.
(6) Seat valve body in case and install one or two
bolts to hold valve body in place.
(7) Tighten valve body bolts alternately and evenly
to 12 N´m (105 in. lbs.) torque.
(8) Install a new primary oil filter seal in the oil
pump inlet bore. Seat the seal in the bore with the
butt end of a hammer, or other suitable tool.
CAUTION: The primary oil filter seal MUST be fully
installed flush against the oil pump body. DO NOT
install the seal onto the filter neck and attempt to
install the filter and seal as an assembly. Damage to
the transmission will result.
(9) Place replacement filter in position on valve
body and into the oil pump.
(10) Install screw to hold filter to valve body.
Tighten screw to 4.5 N´m (40 in. lbs.) torque.
(11) Connect the solenoid and pressure switch
assembly connector.
(12) Install oil pan. Tighten pan bolts to 12 N´m
(105 in. lbs.) torque.
(13) Lower vehicle and fill transmission with
MopartATF +4, type 9602, fluid.
(14) Check and adjust gearshift cable, if necessary.
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 279
VALVE BODY (Continued)

(22) Remove the front bin from the floor console.
(Refer to 23 - BODY/INTERIOR/FLOOR CONSOLE -
REMOVAL).
(23) Reach through the front bin opening of the
floor console to access and remove the two screws
that secure the center floor tunnel bracket to the
instrument panel.
(24) Reach through the front bin opening of the
floor console to access and loosen the two nuts that
secure the center floor tunnel bracket to the studs on
the floor panel transmission tunnel.
(25) Slide the center floor tunnel bracket rearward
in the vehicle far enough to disengage the locating
hole in the lower flange of the top pad from the locat-
ing pin on the instrument panel structural duct (Fig.
25).
(26) Remove the instrument panel top pad from
the instrument panel structural duct.INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
If the top pad is being replaced with a new unit, be
certain to transfer or install the panel outlets and
the passenger side trim bezel to the new unit before
it is installed on the instrument panel structural
duct. (Refer to 24 - HEATING & AIR CONDITION-
ING/DISTRIBUTION/AIR OUTLETS - REMOVAL)
and (Refer to 23 - BODY/INSTRUMENT PANEL/IP
TRIM BEZEL - PASSENGER - REMOVAL).
(1) Position the instrument panel top pad over the
instrument panel structural duct and the studs on
the dash panel near the windshield fence line.
(2) Route the instrument panel wire harness take
out for the glove box lamp and switch unit to the
switch mounting hole in the upper glove box opening
reinforcement.
(3) Reach through the front bin opening of the
floor console to engage the locating hole in the lower
flange of the top pad with the locating pin on the
instrument panel structural duct (Fig. 25).
(4) Reach through the front bin opening of the
floor console to slide the center floor tunnel bracket
forward in the vehicle far enough to capture the
lower flange of the top pad between the bracket and
the structural duct.
(5) Reach through the front bin opening of the
floor console to install and tighten the two screws
that secure the center floor tunnel bracket to the
instrument panel. Tighten the screws to 11.8 N´m
(105 in. lbs.).
Fig. 25 Instrument Panel Top Pad Remove/Install
1 - STRUCTURAL DUCT
2 - LOCATING PIN
3 - INSTRUMENT PANEL TOP PAD
4 - LOWER FLANGE
5 - CENTER FLOOR TUNNEL BRACKET
23 - 54 INSTRUMENT PANEL SYSTEMWJ
INSTRUMENT PANEL TOP PAD (Continued)

OPERATION
OPERATION - HEATER AND AIR CONDITIONER
Outside fresh air enters the vehicle through the
cowl top opening at the base of the windshield, and
passes through a plenum chamber to the HVAC sys-
tem blower housing. Air flow velocity can then be
adjusted with the blower motor speed selector switch
on the a/c heater control panel. The air intake open-
ings must be kept free of snow, ice, leaves, and other
obstructions for the HVAC system to receive a suffi-
cient volume of outside air.
It is also important to keep the air intake openings
clear of debris because leaf particles and other debris
that is small enough to pass through the cowl ple-
num screen can accumulate within the HVAC hous-
ing. The closed, warm, damp and dark environment
created within the HVAC housing is ideal for the
growth of certain molds, mildews and other fungi.
Any accumulation of decaying plant matter provides
an additional food source for fungal spores, which
enter the housing with the fresh air. Excess debris,
as well as objectionable odors created by decaying
plant matter and growing fungi can be discharged
into the passenger compartment during HVAC sys-
tem operation.
Both the manual and AZC heater and air condi-
tioner are blend-air type systems. In a blend-air sys-
tem, a blend door controls the amount of
unconditioned air (or cooled air from the evaporator)
that is allowed to flow through, or around, the heater
core. A temperature control knob on the a/c heater
control panel determines the discharge air tempera-
ture by energizing the blend door actuator, which
operates the blend door. This allows an almost imme-
diate control of the output air temperature of the sys-
tem. The AZC system will have separate blend doors
and temperature controls for each front seat occu-
pant.
The mode control knob on the a/c heater control
panel is used to direct the conditioned air to the
selected system outlets. On manual temperature con-
trol systems, the mode control knob switches engine
vacuum to control the mode doors, which are oper-
ated by vacuum actuators. On AZC systems, the
mode control knob switches electrical current to con-
trol the mode doors, which are operated by electronic
actuators.
The outside air intake can be shut off on manual
temperature control systems by selecting the Recircu-
lation Mode with the mode control knob. The outside
air intake can be shut off on Automatic Zone Control
(AZC) type system by pushing the Recirculation
Mode button. This will operate the recirculation door
that closes off the outside fresh air intake and recir-
culates the air that is already inside the vehicle.The air conditioner for all models is designed for
the use of non-CFC, R-134a refrigerant. The air con-
ditioning system has an evaporator to cool and dehu-
midify the incoming air prior to blending it with the
heated air. This air conditioning system uses a ther-
mal expansion valve to meter refrigerant flow to the
evaporator coil. To maintain minimum evaporator
temperature and prevent evaporator freezing, the
system utilizes an evaporator thermister probe with
the appropriate operating logic located in the body
control module (BCM).
OPERATION - REFRIGERANT SYSTEM SERVICE
PORT
The high pressure service port is located on the liq-
uid line near the receiver/drier. The low pressure ser-
vice port is located on the suction line near the
evaporator at the rear of the engine compartment.
Each of the service ports has a threaded plastic
protective cap installed over it from the factory. After
servicing the refrigerant system, always reinstall
both of the service port caps.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE
The air conditioning system is designed to provide
the passenger compartment with low temperature
and low specific humidity air. The evaporator, located
in the HVAC housing on the dash panel below the
instrument panel, is cooled to temperatures near the
freezing point. As warm damp air passes through the
cooled evaporator, the air transfers its heat to the
refrigerant in the evaporator and the moisture in the
air condenses on the evaporator fins. During periods
of high heat and humidity, an air conditioning sys-
tem will be more effective in the Recirculation Mode.
With the system in the Recirculation Mode, only air
from the passenger compartment passes through the
evaporator. As the passenger compartment air dehu-
midifies, the air conditioning system performance
levels improve.
Humidity has an important bearing on the tempera-
ture of the air delivered to the interior of the vehicle. It
is important to understand the effect that humidity has
on the performance of the air conditioning system.
When humidity is high, the evaporator has to perform a
double duty. It must lower the air temperature, and it
must lower the temperature of the moisture in the air
that condenses on the evaporator fins. Condensing the
moisture in the air transfers heat energy into the evap-
orator fins and tubing. This reduces the amount of heat
the evaporator can absorb from the air. High humidity
greatly reduces the ability of the evaporator to lower
the temperature of the air.
24 - 2 HEATING & AIR CONDITIONINGWJ
HEATING & AIR CONDITIONING (Continued)