Transmission DODGE RAM 2003 Service Repair Manual

CLEANING
Clean the clutch components with solvent and dry
them with compressed air. Do not use rags or shop
towels to dry any of the clutch parts. Lint from such
materials will adhere to component surfaces and
could restrict or block fluid passages after assembly.
INSPECTION
Replace the clutch discs if warped, worn, scored,
burned/charred, the lugs are damaged, or if the fac-
ing is flaking off. Replace the top and bottom pres-
sure plates if scored, warped, or cracked. Be sure the
driving lugs on the pressure and clutch plates are
also in good condition. The lugs must not be bent,
cracked or damaged in any way.
Replace the piston spring and wave spring if either
part is distorted, warped or broken.
Check the lug grooves in the clutch retainer. The
clutch and pressure plates should slide freely in the
slots. Replace the retainer if the grooves are worn or
damaged. Also check action of the check balls in the
retainer and piston. Each check ball must move
freely and not stick.
Replace the retainer bushing if worn, scored, or
doubt exists about bushing condition.
Inspect the piston and retainer seal surfaces for
nicks or scratches. Minor scratches can be removed
with crocus cloth. However, replace the piston and/or
retainer if the seal surfaces are seriously scored.
Check condition of the fiber thrust washer and
metal output shaft thrust washer. Replace either
washer if worn or damaged.
Check condition of the seal rings on the input shaft
and clutch retainer hub. Replace the seal rings only
if worn, distorted, or damaged. The input shaft front
seal ring is teflon with chamfered ends. The rear ring
is metal with interlocking ends.
Check the input shaft for wear, or damage. Replace
the shaft if worn, scored or damaged in any way.
ASSEMBLY
(1) Soak clutch discs in transmission fluid while
assembling other clutch parts.
(2) Install new seal rings on clutch retainer hub
and input shaft if necessary.
(a) Be sure clutch hub seal ring is fully seated in
groove and is not twisted.
(3) Lubricate splined end of input shaft and clutch
retainer with transmission fluid. Then partially press
input shaft into retainer (Fig. 221). Use a suitably
sized press tool to support retainer as close to input
shaft as possible.
(4) Install input shaft retaining ring.
(5) Press the input shaft the remainder of the way
into the clutch retainer.(6) Install new seals on clutch piston. Be sure lip
of each seal faces interior of clutch retainer.
(7) Lubricate lip of piston seals with generous
quantity of MopartDoor Ease. Then lubricate
retainer hub and bore with light coat of transmission
fluid.
(8) Install clutch piston in retainer. Use twisting
motion to seat piston in bottom of retainer. A thin
strip of plastic (about 0.0209thick), can be used to
guide seals into place if necessary.
CAUTION: Never push the clutch piston straight in.
This will fold the seals over causing leakage and
clutch slip. In addition, never use any type of metal
tool to help ease the piston seals into place. Metal
tools will cut, shave, or score the seals.
(9) Install piston spring in retainer and on top of
piston. Concave side of spring faces downward
(toward piston).
(10) Install the spacer ring and wave spring into
the retainer. Be sure spring is completely seated in
retainer groove.
(11) Install pressure plate (Fig. 220). Ridged side
of plate faces downward (toward piston) and flat side
toward clutch pack.
(12) Install first clutch disc in retainer on top of
pressure plate. Then install a clutch plate followed
Fig. 221 Pressing Input Shaft Into Rear Clutch
Retainer
1 - INPUT SHAFT
2 - REAR CLUTCH RETAINER
3 - PRESS RAM
21 - 428 AUTOMATIC TRANSMISSION - 48REDR
REAR CLUTCH (Continued)

by a clutch disc until entire clutch pack is installed
(4 discs and 3 plates are required) (Fig. 220).
(13) Install the reaction plate.
(14) Install selective snap-ring. Be sure snap-ring
is fully seated in retainer groove.
(15) Using a suitable gauge bar and dial indicator,
measure clutch pack clearance (Fig. 222).
(a) Position gauge bar across the clutch drum
with the dial indicator pointer on the pressure
plate (Fig. 222).
(b) Using two small screw drivers, lift the pres-
sure plate and release it.
(c) Zero the dial indicator.
(d) Lift the pressure plate until it contacts the
snap-ring and record the dial indicator reading.
Clearance should be 0.635 - 0.914 mm (0.025 -
0.036 in.). If clearance is incorrect, steel plates, discs,
selective snap ring and pressure plates may have to
be changed.
The selective snap ring thicknesses are:
²0.107 - 0.109 in.
²0.098 - 0.100 in.
²0.095 - 0.097 in.
²0.083 - 0.085 in.
²0.076 - 0.078 in.
²0.071 - 0.073 in.
²0.060 - 0.062 in.
(16) Coat rear clutch thrust washer with petro-
leum jelly and install washer over input shaft and
into clutch retainer (Fig. 223). Use enough petroleum
jelly to hold washer in place.
(17) Set rear clutch aside for installation during
final assembly.
REAR SERVO
DESCRIPTION
The rear (low/reverse) servo consists of a single
stage or diameter piston and a spring loaded plug.
The spring is used to cushion the application of the
rear (low/reverse) band.
OPERATION
While in the de-energized state (no pressure
applied), the piston is held up in its bore by the pis-
ton spring. The plug is held down in its bore, in the
piston, by the plug spring. When pressure is applied
to the top of the piston, the plug is forced down in its
bore, taking up any clearance. As the piston moves, it
causes the plug spring to compress, and the piston
moves down over the plug. The piston continues to
move down until it hits the shoulder of the plug and
fully applies the band. The period of time from the
initial application, until the piston is against the
shoulder of the plug, represents a reduced shocking
of the band that cushions the shift.
Fig. 222 Checking Rear Clutch Pack Clearance
1 - DIAL INDICATOR
2 - PRESSURE PLATE
3 - SNAP-RING
4-STAND
5 - REAR CLUTCH
6 - GAUGE BAR
Fig. 223 Installing Rear Clutch Thrust Washer
1 - REAR CLUTCH RETAINER
2 - REAR CLUTCH THRUST WASHER
DRAUTOMATIC TRANSMISSION - 48RE 21 - 429
REAR CLUTCH (Continued)

DISASSEMBLY
(1) Remove small snap-ring and remove plug and
spring from servo piston (Fig. 224).
(2) Remove and discard servo piston seal ring.
CLEANING
Remove and discard the servo piston seal ring (Fig.
225). Then clean the servo components with solvent
and dry with compressed air. Replace either spring if
collapsed, distorted or broken. Replace the plug and
piston if cracked, bent, or worn. Discard the servo
snap-rings and use new ones at assembly.
ASSEMBLY
(1) Lubricate piston and guide seals (Fig. 226)
with petroleum jelly. Lubricate other servo parts with
MopartATF +4, Automatic Transmission fluid.
(2) Install new seal ring on servo piston.(3) Assemble piston, plug, spring and new snap-
ring.
(4) Lubricate piston seal lip with petroleum jelly.
SHIFT MECHANISM
DESCRIPTION
The gear shift mechanism provides six shift posi-
tions which are:
²PARK (P)
²REVERSE (R)
²NEUTRAL (N)
²DRIVE (D)
²Manual SECOND (2)
²Manual LOW (1)
OPERATION
Manual LOW (1) range provides first gear only.
Overrun braking is also provided in this range. Man-
ual SECOND (2) range provides first and second gear
only.
DRIVE range provides first, second third and over-
drive fourth gear ranges. The shift into overdrive
fourth gear range occurs only after the transmission
has completed the shift into D third gear range. No
further movement of the shift mechanism is required
to complete the 3-4 shift.
The fourth gear upshift occurs automatically when
the overdrive selector switch is in the ON position.
No upshift to fourth gear will occur if any of the fol-
lowing are true:
²The transmission fluid temperature is below 10É
C (50É F) or above 121É C (250É F).
²The shift to third is not yet complete.
²Vehicle speed is too low for the 3-4 shift to occur.
²Battery temperature is below -5É C (23É F).
Fig. 224 Rear Servo Components
1 - SNAP-RING
2 - PISTON SEAL
3 - PISTON PLUG
4 - SPRING RETAINER
5 - SNAP-RING
6 - PISTON SPRING
7 - CUSHION SPRING
8 - PISTON
Fig. 225 Rear Servo Components
1 - SNAP-RING
2 - PISTON SEAL
3 - PISTON PLUG
4 - SPRING RETAINER
5 - SNAP-RING
6 - PISTON SPRING
7 - CUSHION SPRING
8 - PISTON
Fig. 226 Rear Servo Components
1 - SNAP-RING
2 - PISTON SEAL
3 - PISTON PLUG
4 - SPRING RETAINER
5 - SNAP-RING
6 - PISTON SPRING
7 - CUSHION SPRING
8 - PISTON
21 - 430 AUTOMATIC TRANSMISSION - 48REDR
REAR SERVO (Continued)

SOLENOID
DESCRIPTION
The typical electrical solenoid used in automotive
applications is a linear actuator. It is a device that
produces motion in a straight line. This straight line
motion can be either forward or backward in direc-
tion, and short or long distance.
A solenoid is an electromechanical device that uses
a magnetic force to perform work. It consists of a coil
of wire, wrapped around a magnetic core made from
steel or iron, and a spring loaded, movable plunger,
which performs the work, or straight line motion.
The solenoids used in transmission applications
are attached to valves which can be classified asnor-
mally openornormally closed. Thenormally
opensolenoid valve is defined as a valve which
allows hydraulic flow when no current or voltage is
applied to the solenoid. Thenormally closedsole-
noid valve is defined as a valve which does not allow
hydraulic flow when no current or voltage is applied
to the solenoid. These valves perform hydraulic con-
trol functions for the transmission and must there-
fore be durable and tolerant of dirt particles. For
these reasons, the valves have hardened steel pop-
pets and ball valves. The solenoids operate the valves
directly, which means that the solenoids must have
very high outputs to close the valves against the siz-
able flow areas and line pressures found in current
transmissions. Fast response time is also necessary
to ensure accurate control of the transmission.
The strength of the magnetic field is the primary
force that determines the speed of operation in a par-
ticular solenoid design. A stronger magnetic field will
cause the plunger to move at a greater speed than a
weaker one. There are basically two ways to increase
the force of the magnetic field:
1. Increase the amount of current applied to the
coil or
2. Increase the number of turns of wire in the coil.
The most common practice is to increase the num-
ber of turns by using thin wire that can completely
fill the available space within the solenoid housing.
The strength of the spring and the length of the
plunger also contribute to the response speed possi-
ble by a particular solenoid design.
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 voltageacross 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. 227) 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.
Fig. 227 Transmission Output Speed Sensor
1 - TRANSMISSION OUTPUT SHAFT SPEED SENSOR
2 - SEAL
DRAUTOMATIC TRANSMISSION - 48RE 21 - 431

THROTTLE VALVE CABLE
DESCRIPTION
Transmission throttle valve cable (Fig. 228) adjust-
ment is extremely important to proper operation.
This adjustment positions the throttle valve, which
controls shift speed, quality, and part-throttle down-
shift 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. 229). 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 - THROTTLE VALVE CABLE
A correctly adjusted throttle valve cable will cause
the throttle lever on the transmission to move simul-
taneously with the throttle body lever from the idle
position. Proper adjustment will allow simultaneous
movement without causing the transmission throttlelever to either move ahead of, or lag behind the lever
on the throttle body.
ADJUSTMENT VERIFICATION
(1) Turn ignition key to OFF position.
(2) Remove air cleaner.
(3) Verify that lever on throttle body is at curb idle
position (Fig. 230). Then verify that the transmission
throttle lever (Fig. 231) is also at idle (fully forward)
position.
(4) Slide cable off attachment stud on throttle body
lever.
(5) Compare position of cable end to attachment
stud on throttle body lever:
²Cable end and attachment stud should be
aligned (or centered on one another) to within 1 mm
(0.039 in.) in either direction (Fig. 232).
²If cable end and attachment stud are misaligned
(off center), cable will have to be adjusted as
described in Throttle Valve Cable Adjustment proce-
dure.
(6) Reconnect cable end to attachment stud. Then
with aid of a helper, observe movement of transmis-
sion throttle lever and lever on throttle body.
Fig. 228 Throttle Valve Cable Attachment - At
Engine
1 - THROTTLE VALVE CABLE
2 - CABLE BRACKET
3 - THROTTLE BODY LEVER
4 - ACCELERATOR CABLE
5 - SPEED CONTROL CABLE
Fig. 229 Throttle Valve Cable at Throttle Linkage
1 - THROTTLE LINKAGE
2 - THROTTLE VALVE CABLE LOCKING CLIP
3 - THROTTLE VALVE CABLE
21 - 432 AUTOMATIC TRANSMISSION - 48REDR

²If both levers move simultaneously from idle to
half-throttle and back to idle position, adjustment is
correct.
²If transmission throttle lever moves ahead of, or
lags behind throttle body lever, cable adjustment will
be necessary. Or, if throttle body lever prevents
transmission lever from returning to closed position,
cable adjustment will be necessary.
ADJUSTMENT PROCEDURE
(1) Turn ignition switch to OFF position.
(2) Remove air cleaner if necessary.
(3) Disconnect cable end from attachment stud.
Carefully slide cable off stud. Do not pry or pull
cable off.
(4) Verify that transmission throttle lever is in
fully closed position. Then be sure lever on throttle
body is at curb idle position.
(5) Pry the T.V. cable lock (A) into the UP position
(Fig. 232). This will unlock the cable and allow for
readjustment.
(6) Apply just enough tension on the T.V. cable (B)
to remove any slack in the cable.Pulling too tight
will cause the T.V. lever on the transmission to
move out of its idle position, which will result
Fig. 230 Throttle Valve Cable Attachment - At
Engine
1 - THROTTLE VALVE CABLE
2 - CABLE BRACKET
3 - THROTTLE BODY LEVER
4 - ACCELERATOR CABLE
5 - SPEED CONTROL CABLE
Fig. 231 Throttle Valve Cable at Transmission
1 - TRANSMISSION SHIFTER CABLE
2 - THROTTLE VALVE CABLE
3 - TRANSFER CASE SHIFTER CABLE
4 - TRANSFER CASE SHIFTER CABLE BRACKET RETAINING
BOLT(1OR2)
5 - THROTTLE VALVE CABLE BRACKET RETAINING BOLT
6 - ELECTRICAL CONNECTORS
7 - TRANSMISSION FLUID LINES
Fig. 232 Throttle Valve Cable at Throttle Linkage
1 - THROTTLE LINKAGE
2 - THROTTLE VALVE CABLE LOCKING CLIP
3 - THROTTLE VALVE CABLE
DRAUTOMATIC TRANSMISSION - 48RE 21 - 433
THROTTLE VALVE CABLE (Continued)

in an incorrect T.V. cable adjustment.Slide the
sheath of the T.V. cable (D) back and forth until the
centerlines of the T.V. cable end (B) and the throttle
bell crank lever (C) are aligned within one millimeter
(1mm) (Fig. 232).
(7) While holding the T.V. cable in the set position
push the T.V. cable lock (A) into the down position
(Fig. 232). This will lock the present T.V. cable
adjustment.
NOTE: Be sure that as the cable is pulled forward
and centered on the throttle lever stud, the cable
housing moves smoothly with the cable. Due to the
angle at which the cable housing enters the spring
housing, the cable housing may bind slightly and
create an incorrect adjustment.
(8) Reconnect the T.V. cable (B) to the throttle
bellcrank lever (C).
(9) Check cable adjustment. Verify transmission
throttle lever and lever on throttle body move simul-
taneously.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 233) 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 torque
converter 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 all transmission fluid
cooler(s) and lines.
Fig. 233 Torque Converter Assembly
1 - TURBINE
2 - IMPELLER
3 - HUB
4-STATOR
5 - FRONT COVER
6 - CONVERTER CLUTCH DISC
7 - DRIVE PLATE
21 - 434 AUTOMATIC TRANSMISSION - 48REDR
THROTTLE VALVE CABLE (Continued)

IMPELLER
The impeller (Fig. 234) 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 members of the system.
Fig. 234 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
DRAUTOMATIC TRANSMISSION - 48RE 21 - 435
TORQUE CONVERTER (Continued)

TURBINE
The turbine (Fig. 235) 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. 235 Turbine
1 - TURBINE VANE 4 - PORTION OF TORQUE CONVERTER COVER
2 - ENGINE ROTATION 5 - ENGINE ROTATION
3 - INPUT SHAFT 6 - OIL FLOW WITHIN TURBINE SECTION
21 - 436 AUTOMATIC TRANSMISSION - 48REDR
TORQUE CONVERTER (Continued)

STATOR
The stator assembly (Fig. 236) 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. 237).
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. 238) 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 impeller
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. 236 Stator Components
1 - CAM (OUTER RACE)
2 - ROLLER
3 - SPRING
4 - INNER RACE
Fig. 237 Stator Location
1-STATOR
2 - IMPELLER
3 - FLUID FLOW
4 - TURBINE
Fig. 238 Torque Converter Clutch (TCC)
1 - IMPELLER FRONT COVER
2 - THRUST WASHER ASSEMBLY
3 - IMPELLER
4-STATOR
5 - TURBINE
6 - PISTON
7 - FRICTION DISC
DRAUTOMATIC TRANSMISSION - 48RE 21 - 437
TORQUE CONVERTER (Continued)