2002 CHRYSLER CARAVAN oil

ADJUSTMENTS
THROTTLE VALVE LINKAGE ADJUSTMENT
The throttle valve linkage adjustment is very
important to proper transaxle operation. This adjust-
ment positions a valve which controls shift speed,
shift quality, and part throttle downshift sensitivity.
If the setting is too short, early shifts and slippage
between shifts may occur. If the setting is too long,
shifts may be delayed and part throttle downshifts
may be very sensitive.
LINKAGE ADJUSTMENT PROCEDURE
(1) Perform transaxle throttle valve linkage
adjustment while engine is at normal operating tem-
perature.
(2) Using small screwdriver, disengage adjustment
lock at transaxle.
(3) Rotate lever at transaxle all the way to the left
side of vehicle against stop.
(4) Slide cable adjuster until cable core end
touches clip at throttle valve lever.
(5) Press adjuster lock (Fig. 228) to retain setting.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 229) 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.
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. 228 Throttle Valve Cable Adjustment Lock
1 - ADJUSTER LOCK
Fig. 229 Torque Converter Assembly
1 - TURBINE
2 - IMPELLER
3 - HUB
4-STATOR
5 - CONVERTER CLUTCH DISC
6 - DRIVE PLATE
21 - 122 31TH AUTOMATIC TRANSAXLERS
THROTTLE VALVE CABLE (Continued)
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IMPELLER
The impeller (Fig. 230) is an integral part of the
converter housing. The impeller consists of curved
blades placed radially along the inside of the housing
on the transmission side of the converter. As the con-
verter housing is rotated by the engine, so is the
impeller, because they are one and the same and are
the driving member of the system.
Fig. 230 Impeller
1 - ENGINE FLEXPLATE 4 - ENGINE ROTATION
2 - OIL FLOW FROM IMPELLER SECTION INTO TURBINE
SECTION5 - ENGINE ROTATION
3 - IMPELLER VANES AND COVER ARE INTEGRAL
RS31TH AUTOMATIC TRANSAXLE21 - 123
TORQUE CONVERTER (Continued)
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TURBINE
The turbine (Fig. 231) is the output, or driven,
member of the converter. The turbine is mounted
within the housing opposite the impeller, but is not
attached to the housing. The input shaft is inserted
through the center of the impeller and splined into
the turbine. The design of the turbine is similar to
the impeller, except the blades of the turbine are
curved in the opposite direction.
Fig. 231 Turbine
1 - TURBINE VANE
2 - ENGINE ROTATION
3 - INPUT SHAFT
4 - PORTION OF TORQUE CONVERTER COVER5 - ENGINE ROTATION
6 - OIL FLOW WITHIN TURBINE SECTION
21 - 124 31TH AUTOMATIC TRANSAXLERS
TORQUE CONVERTER (Continued)
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STATOR
The stator assembly (Fig. 232) is mounted on a sta-
tionary shaft which is an integral part of the oil
pump. The stator is located between the impeller and
turbine within the torque converter case (Fig. 233).
The stator contains an over-running clutch, which
allows the stator to rotate only in a clockwise direc-
tion. When the stator is locked against the over-run-
ning clutch, the torque multiplication feature of the
torque converter is operational.
TORQUE CONVERTER CLUTCH (TCC)
The TCC (Fig. 234) was installed to improve the
efficiency of the torque converter that is lost to the
slippage of the fluid coupling. Although the fluid cou-
pling provides smooth, shock±free power transfer, it
is natural for all fluid couplings to slip. If the impel-
ler and turbine were mechanically locked together, a
zero slippage condition could be obtained. A hydraulic
piston was added to the turbine, and a friction mate-
rial was added to the inside of the front cover to pro-
vide this mechanical lock-up.
Fig. 232 Stator Components
1 - CAM (OUTER RACE)
2 - ROLLER
3 - SPRING
4 - INNER RACE
Fig. 233 Stator Location
1-STATOR
2 - IMPELLER
3 - FLUID FLOW
4 - TURBINE
Fig. 234 Torque Converter Clutch (TCC)
1 - IMPELLER FRONT COVER
2 - THRUST WASHER ASSEMBLY
3 - IMPELLER
4-STATOR
5 - TURBINE
6 - PISTON
7 - FRICTION DISC
RS31TH AUTOMATIC TRANSAXLE21 - 125
TORQUE CONVERTER (Continued)
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STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft (Fig. 236).
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 to the front
cover's friction material, 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 engagement and disengagement of the TCC
are automatic and controlled by the Powertrain Con-
trol Module (PCM). The engagement cannot be acti-
vated in the lower gears because it eliminates the
torque multiplication effect of the torque converternecessary for acceleration. Inputs that determine
clutch engagement are: coolant temperature, vehicle
speed and throttle position. The torque converter
clutch is engaged by the clutch solenoid on the valve
body. The clutch will engage at approximately 56
km/h (35 mph) with light throttle, after the shift to
third gear.
REMOVAL
(1) Remove transmission and torque converter
from vehicle. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 31TH - REMOVAL)
(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 converter hub and 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. 237). 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.
Fig. 236 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
RS31TH AUTOMATIC TRANSAXLE21 - 127
TORQUE CONVERTER (Continued)
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VALVE BODY
REMOVAL
(1) Disconnect battery negative cable.
(2) Disconnect throttle valve cable from throttle
valve lever at transaxle.
(3) Disconnect gearshift cable from gearshift lever
at transaxle.
(4) Disconnect torque converter clutch solenoid
connector.
(5) Raise vehicle on hoist.
(6) Remove transaxle oil pan bolts (Fig. 297).
(7) Separate oil pan from case and drain fluid into
suitable container (Fig. 298).(8) Remove oil filter-to-valve body screws (Fig.
299).
(9) Remove oil filter and gasket (Fig. 300).
Fig. 297 Transaxle Oil Pan Bolts
1 - TRANSAXLE OIL PAN
2 - OIL PAN BOLTS
Fig. 298 Transaxle Oil Pan
1 - TRANSAXLE OIL PAN
2 - OIL FILTER
Fig. 299 Oil Filter Screws
1 - SCREWDRIVER HANDLE
2 - SPECIAL TOOL L-4553
3 - OIL FILTER SCREWS (2)
4 - OIL FILTER
Fig. 300 Oil Filter and Gasket
1 - OIL FILTER
2 - GASKET
3 - VALVE BODY
21 - 146 31TH AUTOMATIC TRANSAXLERS
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(3) Separate transfer and separator plate from
valve body assembly (Fig. 309). Note check ball loca-
tions (Fig. 310) for proper reassembly.(4) Remove throttle valve shaft-to-manual valve
shaft e-clip (Fig. 311). Note orientation of washer and
seal (Fig. 312).
Fig. 309 Separate Transfer Plate and Separator
Plate from Valve Body
1 - SEPARATOR PLATE
2 - TRANSFER PLATE
3 - OIL SCREEN
4 - VALVE BODY
Fig. 310 Steel Ball Locations
1 - MANUAL VALVE
2 - STEEL BALLS (8)
3 - STEEL BALLS
Fig. 311 Remove Throttle Shaft E-Clip
1 - MANUAL VALVE LEVER ASSEMBLY
2 - THROTTLE VALVE LEVER ASSEMBLY
3 - SCREWDRIVER
4 - ªEº CLIP
Fig. 312 Throttle Shaft E-Clip, Washer, and Seal
1 - MANUAL VALVE LEVER ASSEMBLY
2 - OIL SEAL
3 - ªEº CLIP
4 - THROTTLE VALVE LEVER ASSEMBLY
5 - WASHER
RS31TH AUTOMATIC TRANSAXLE21 - 149
VALVE BODY (Continued)
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valve or plug edges. Squareness of these edges is
vitally important. These edges prevent foreign matter
from lodging between the valves, plugs and bore.
INSPECTION
Inspect the throttle and manual valve levers and
shafts. Do not attempt to straighten a bent shaft or
correct a loose lever. Replace these components if
worn, bent, loose or damaged in any way.
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.
Inspect the valves and plugs for scratches, burrs,
nicks, or scores. Also inspect the coating on the alu-
minum valves and plugs. If the coating is damaged
or worn through, the valve (or valve body) should be
replaced.
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.
ASSEMBLY
(1) Install shift/shuttle valves and springs as
shown in (Fig. 320).
(2) Install torque converter clutch solenoid, spring,
and plug as shown in (Fig. 319).
(3) Install governor plugs as shown in (Fig. 318).
(4) Install pressure regulator and manual control
springs and valves as shown in (Fig. 317).
(5) Install pressure regulator spring retainer/ad-
justing screw bracket (Fig. 321).
(6) Install manual valve from valve body (Fig.
322).
Fig. 321 Pressure Regulator and Adjusting Screw
Bracket
1 - SCREWDRIVER HANDLE
2 - PRESSURE REGULATOR SPRING RETAINER AND
ADJUSTING SCREW BRACKET
3 - VALVE BODY
4 - SCREWS
Fig. 322 Install Manual Valve
1 - MANUAL VALVE
2 - VALVE BODY
RS31TH AUTOMATIC TRANSAXLE21 - 155
VALVE BODY (Continued)
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