2003 JEEP GRAND CHEROKEE piston ring

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)

(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
21 - 276 AUTOMATIC TRANSMISSION - 545RFEWJ
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)

LIFTGATE
REMOVAL
CAUTION: DO NOT DISCONNECT THE SUPPORT ROD
CYLINDERS WITH THE LIFTGATE CLOSED. THE SUP-
PORT ROD PISTONS ARE OPERATED BY HIGH PRES-
SURE GAS. THIS PRESSURE COULD CAUSE DAMAGE
AND /OR PERSONAL INJURY IF THEY ARE REMOVED
WHILE THE PISTONS ARE COMPRESSED.
(1) Open the liftgate. Support the liftgate for ease
of repair.
(2) Remove the liftgate trim panel.
(3) Remove the prop rods from the liftgate.
(4) Unplug the wire harnesses and disconnect the
washer hose.
(5) Mark the hinge location with a wax pencil or
other suitable device (Fig. 5).
(6) Remove the hinge screws and remove liftgate
from vehicle.
INSTALLATION
(1) Position the liftgate on the vehicle and align
the witness marks.
(2) Install the hinge screws at liftgate. Tighten
hinge screws to 28N´m (21ft. lbs.).
(3) Connect the wire harnesses and the washer
hose.
(4) Install the trim panel.
(5) Install the prop rods.
(6) Close the liftgate and check for proper latching
and alignment.
ADJUSTMENTS
LIFTGATE ADJUSTMENT
The position of the liftgate can be adjusted upward
or downward by the use of slots in the hinge. An
inward or outward adjustment is achieved by use of
slots in the body. If an inward or outward adjustment
is needed, use 3MŸ Fast and Firm or equivalent on
the hinge to body mating surface as a sealant.
TRIM PANEL
REMOVAL
REMOVAL - LIFTGATE TRIM PANEL
NOTE: The liftgate trim panel is attached with
screws and spring clips.
(1) Raise the liftgate.
(2) Remove the screws securing the liftgate trim
panel to the liftgate (Fig. 6).
(3) Disconnect the rear window defroster wires.
(4) Using a trim stick, or other suitable tool, pry
the liftgate trim panel off the liftgate.
Fig. 5 Liftgate
1 - HINGE
2 - LIFTGATE
Fig. 6 Liftgate Trim Panel
1 - LIFTGATE
2 - LIFTGATE TRIM PANEL
WJDECKLID/HATCH/LIFTGATE/TAILGATE 23 - 9