sensor DODGE RAM 2003 Service Repair Manual

(4) Lubricate o-ring on pressure sensor with trans-
mission fluid.
(5) Align pressure sensor to bore in governor body.
(6) Push pressure sensor into governor body.
(7) Lubricate o-ring, on pressure solenoid, with
transmission fluid.
(8) Align pressure solenoid to bore in governor
body (Fig. 85).
(9) Push solenoid into governor body.
(10) Place solenoid retainer in position on governor
(Fig. 86).
(11) Install screws to hold pressure solenoid
retainer to governor body.
(12) Engage wire connectors into pressure sensor
and solenoid (Fig. 87).
(13) Install transmission fluid pan and (new) filter.(14) Lower vehicle and road test to verify repair.
EXTENSION HOUSING SEAL
REMOVAL
(1) Raise vehicle.
(2) Mark propeller shaft and axle yoke for align-
ment reference.
(3) Disconnect and remove propeller shaft.
(4) Remove old seal with a screw mounted in a
slide hammer.
INSTALLATION
(1) Place seal in position on overdrive housing.
(2) Drive seal into overdrive housing with Seal
Installer 9037 (Fig. 88).
(3) Carefully guide propeller shaft slip yoke into
housing and onto output shaft splines. Align marks
made at removal and connect propeller shaft to rear
axle pinion yoke.
Fig. 85 Pressure Solenoid and O-ring
1 - PRESSURE SOLENOID
2 - O-RING
3 - GOVERNOR
Fig. 86 Pressure Solenoid Retainer
1 - PRESSURE SOLENOID RETAINER
2 - GOVERNOR
Fig. 87 Governor Solenoid And Pressure Sensor
1 - PRESSURE SENSOR
2 - PRESSURE SOLENOID
3 - GOVERNOR
Fig. 88 Installing Overdrive Housing Yoke Seal
1 - SPECIAL TOOL 9037
2 - SPECIAL TOOL C-4171
21 - 380 AUTOMATIC TRANSMISSION - 48REDR
ELECTRONIC GOVERNOR (Continued)

vehicle if necessary to bring fluid temperature up to
normal hot operating temperature of 82ÉC (180ÉF).
(2) Position vehicle on level surface.
(3) Start and run engine at curb idle speed.
(4) Apply parking brakes.
(5) Shift transmission momentarily into all gear
ranges. Then shift transmission back to NEUTRAL.
(6) Clean top of filler tube and dipstick to keep
dirt from entering tube.
(7) Remove dipstick (Fig. 89) and check fluid level
as follows:
(a) Correct acceptable level is in crosshatch area.
(b) Correct maximum level is to MAX arrow
mark.
(c) Incorrect level is at or below MIN line.
(d) If fluid is low, add only enough MopartAT F
+4, type 9602, to restore correct level. Do not over-
fill.
PROCEDURE TWO
(1) Start engine and apply parking brake.
(2) Shift the transmission into DRIVE for approxi-
mately 2 seconds.
(3) Shift the transmission into REVERSE for
approximately 2 seconds.
(4) Shift the transmission into PARK.
(5) Hook up DRBtscan tool and select engine.(6) Select sensors.
(7) Read the transmission temperature value.
(8) Compare the fluid temperature value with the
chart.
(9) Adjust transmission fluid level shown on the
dipstick according to the chart (Fig. 90).
NOTE: After adding any fluid to the transmission,
wait a minimum of 2 minutes for the oil to fully
drain from the fill tube into the transmission before
rechecking the fluid level.
(10) Check transmission for leaks.
Fig. 90 48RE Fluid Fill Graph
Fig. 89 Dipstick Fluid Level MarksÐTypical
1 - DIPSTICK
2 - MAXIMUM CORRECT FLUID LEVEL
3 - ACCEPTABLE FLUID LEVEL
21 - 382 AUTOMATIC TRANSMISSION - 48REDR
FLUID AND FILTER (Continued)

(4) Raise the vehicle.
(5) Place the transmission manual shift lever in
the ªPARKº detent (rearmost) position and rotate
prop shaft to ensure transmission is in PARK.
(6) Route the gearshift cable through the transmis-
sion mounting bracket and secure the cable by snap-
ping the cable retaining ears into the transmission
bracket and snapping the cable eyelet on the manual
shift lever ball stud.
(7) Lower vehicle.
(8) Lock the shift cable adjustment by pressing the
cable adjuster lock tab downward until it snaps into
place.
(9) Check for proper operation of the transmission
range sensor.
(10) Adjust the gearshift cable and BTSI mecha-
nism as necessary.
ADJUSTMENTS
GEARSHIFT CABLE
Check adjustment by starting the engine in PARK
and NEUTRAL. Adjustment is CORRECT if the
engine starts only in these positions. Adjustment is
INCORRECT if the engine starts in one but not both
positions. If the engine starts in any position other
than PARK or NEUTRAL, or if the engine will not
start at all, the transmission range sensor may be
faulty.
Gearshift Adjustment Procedure
(1) Shift transmission into PARK.
(2) Release cable adjuster lock tab (underneath the
steering column) (Fig. 110) to unlock cable.
(3) Raise vehicle.
(4) Disengage the cable eyelet from the transmis-
sion manual shift lever.(5) Verify transmission shift lever is in PARK
detent by moving lever fully rearward. Last rearward
detent is PARK position.
(6) Verify positive engagement of transmission
park lock by attempting to rotate propeller shaft.
Shaft will not rotate when park lock is engaged.
(7) Snap the cable eyelet onto the transmission
manual shift lever.
(8) Lower vehicle.
(9) Lock shift cable by pressing cable adjuster lock
tab downward until it snaps into place.
(10) Check engine starting. Engine should start
only in PARK and NEUTRAL
Fig. 110 Gearshift Cable at Steering Column
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 391
GEARSHIFT CABLE (Continued)

DISASSEMBLY
(1) Remove transmission speed sensor and o-ring
seal from overdrive case (Fig. 125).
(2) Remove overdrive piston thrust bearing (Fig.
126).
OVERDRIVE PISTON
(1) Remove overdrive piston thrust plate (Fig.
127). Retain thrust plate. It is a select fit part and
may possibly be reused.
(2) Remove intermediate shaft spacer (Fig. 128).
Retain spacer. It is a select fit part and may possibly
be reused.
Fig. 125 Transmission Speed Sensor
1 - SOCKET AND WRENCH
2 - SPEED SENSOR
3 - O-RING
Fig. 126 Overdrive Piston Thrust Bearing Removal/
Installation
1 - THRUST BEARING
2 - OVERDRIVE PISTON
3 - THRUST PLATE
Fig. 127 Overdrive Piston Thrust Plate Removal/
Installation
1 - OVERDRIVE PISTON
2 - OVERDRIVE PISTON SPACER (SELECT FIT)
Fig. 128 Intermediate Shaft Spacer Location
1 - INTERMEDIATE SHAFT
2 - INTERMEDIATE SHAFT SPACER (SELECT FIT)
DRAUTOMATIC TRANSMISSION - 48RE 21 - 399
OVERDRIVE UNIT (Continued)

(b) Position Gauge Tool 6311 across face of over-
drive case (Fig. 178). Then position Dial Caliper
C-4962 over gauge tool.
(c) Extend sliding scale of dial caliper downward
through gauge tool slot until scale contacts end of
Gauge Alignment Tool 6312. Lock scale in place.
Remove dial caliper tool and note distance mea-
sured (Fig. 178).
(d) Select proper thickness end play spacer from
spacer chart based on distance measured (Fig.
179).
(e) Remove Gauge Alignment Tool 6312.
OD THRUST PLATE SELECTION
(1) Place overdrive unit in vertical position. Mount
it on blocks, or in workbench with appropriate size
mounting hole cut into it. Be sure unit is facingupward for access to direct clutch hub. Also be sure
output shaft is not loaded and internal components
are moved rearward for accurate measurement.
(2) Determine correct thickness overdrive piston
thrust plate as follows:
(a) Position Gauge Tool 6311 across face of over-
drive case. Then position Dial Caliper C-4962 over
gauge tool (Fig. 180).
(b) Measure distance to clutch hub thrust bear-
ing seat at four points 90É apart. Then average
measurements by adding them and dividing by 4.
(c) Select and install required thrust plate from
information in thrust plate chart (Fig. 181).
(3) Leave Alignment Tool 6227-2 in place. Tool will
keep planetary and clutch hub splines in alignment
until overdrive unit is ready for installation on trans-
mission.
(4) Transmission speed sensor can be installed at
this time if desired. However, it is recommended that
sensor not be installed until after overdrive unit is
secured to transmission.
Fig. 177 Overdrive Clutch Pack Retaining Ring
Installation
1 - OVERDRIVE CLUTCH PACK RETAINING RING
Fig. 178 Shaft End Play Measurement
1 - SPECIAL TOOL 6312
2 - SPECIAL TOOL 6311
3 - SPECIAL TOOL C-4962
Fig. 179 Intermediate Shaft End Play Spacer
Selection
Fig. 180 Overdrive Piston Thrust Plate Measurement
1 - SPECIAL TOOL 6311
2 - DIRECT CLUTCH HUB THRUST BEARING SEAT
3 - SPECIAL TOOL C-4962
DRAUTOMATIC TRANSMISSION - 48RE 21 - 413
OVERDRIVE UNIT (Continued)

OVERDRIVE PISTON
(1) Install new seals on overdrive piston.
(2) Stand transmission case upright on bellhous-
ing.
(3) Position Guide Ring 8114-1 on outer edge of
overdrive piston retainer.
(4) Position Seal Guide 8114-3 on inner edge of
overdrive piston retainer.
(5) Install overdrive piston in overdrive piston
retainer by:
(a) Aligning locating lugs on overdrive piston to
the two mating holes in retainer.
(b) Lubricate overdrive piston seals with Mopart
ATF+4.
(c) Install piston over Seal Guide 8114-3 and
inside Guide Ring 8114-1.
(d) Push overdrive piston into position in
retainer.
(e) Verify that the locating lugs entered the lug
bores in the retainer.
(6) Install intermediate shaft spacer on intermedi-
ate shaft.
(7) Install overdrive piston thrust plate on over-
drive piston.
(8) Install overdrive piston thrust bearing on over-
drive piston.
(9) Install transmission speed sensor and o-ring
seal in overdrive case.
INSTALLATION
(1) Be sure overdrive unit Alignment Tool 6227-2
is fully seated before moving unit. If tool is not
seated and gear splines rotate out of alignment, over-
drive unit will have to be disassembled in order to
realign splines.
(2) If overdrive piston retainer was not removed
during service and original case gasket is no longer
reusable, prepare new gasket by trimming it.(3) Cut out old case gasket around piston retainer
with razor knife (Fig. 182).
(4) Use old gasket as template and trim new gas-
ket to fit.
(5) Position new gasket over piston retainer and
on transmission case. Use petroleum jelly to hold
gasket in place if necessary. Do not use any type of
sealer to secure gasket. Use petroleum jelly only.
(6) Install selective spacer on intermediate shaft, if
removed. Spacer goes in groove just rearward of
shaft rear splines (Fig. 183).
(7) Install thrust bearing in overdrive unit sliding
hub. Use petroleum jelly to hold bearing in position.
CAUTION: Be sure the shoulder on the inside diam-
eter of the bearing is facing forward.
(8) Verify that splines in overdrive planetary gear
and overrunning clutch hub are aligned with Align-
Fig. 181 Overdrive Piston Thrust Plate Selection
Fig. 182 Trimming Overdrive Case Gasket
1 - GASKET
2 - SHARP KNIFE
Fig. 183 Intermediate Shaft Selective Spacer
Location
1 - SELECTIVE SPACER
2 - SPACER GROOVE
3 - INTERMEDIATE SHAFT
21 - 414 AUTOMATIC TRANSMISSION - 48REDR
OVERDRIVE UNIT (Continued)

ment Tool 6227-2. Overdrive unit cannot be installed
if splines are not aligned. If splines have rotated out
of alignment, unit will have to be disassembled to
realign splines.
(9)
Carefully slide Alignment Tool 6227-2 out of over-
drive planetary gear and overrunning clutch splines.
(10) Raise overdrive unit and carefully slide it
straight onto intermediate shaft. Insert park rod into
park lock reaction plug at same time. Avoid tilting
overdrive during installation as this could cause
planetary gear and overrunning clutch splines to
rotate out of alignment. If this occurs, it will be nec-
essary to remove and disassemble overdrive unit to
realign splines.
(11) Work overdrive unit forward on intermediate
shaft until seated against transmission case.
(12) Install bolts attaching overdrive unit to trans-
mission unit. Tighten bolts in diagonal pattern to 34
N´m (25 ft-lbs).
(13) Connect the transmission speed sensor and
overdrive wiring connectors.
(14) Install the transfer case, if equipped.
(15) Align and install rear propeller shaft, if nec-
essary. (Refer to 3 - DIFFERENTIAL & DRIVELINE/
PROPELLER SHAFT/PROPELLER SHAFT -
INSTALLATION)
OVERRUNNING CLUTCH
CAM/OVERDRIVE PISTON
RETAINER
DESCRIPTION
The overrunning clutch (Fig. 184) consists of an
inner race, an outer race (or cam), rollers and
springs, and the spring retainer. The number of roll-
ers and springs depends on what transmission and
which overrunning clutch is being dealt with.
OPERATION
As the inner race is rotated in a clockwise direction
(as viewed from the front of the transmission), the
race causes the rollers to roll toward the springs,
causing them to compress against their retainer. The
compression of the springs increases the clearance
between the rollers and cam. This increased clear-
ance between the rollers and cam results in a free-
wheeling condition. When the inner race attempts to
rotate counterclockwise, the action causes the rollers
to roll in the same direction as the race, aided by the
pushing of the springs. As the rollers try to move in
the same direction as the inner race, they are
wedged between the inner and outer races due to the
design of the cam. In this condition, the clutch is
locked and acts as one unit.
DISASSEMBLY
(1) Remove the overdrive piston (Fig. 185).
(2) Remove the overdrive piston retainer bolts.
(3) Remove overdrive piston retainer.
(4) Remove case gasket.
Fig. 185 Overdrive Piston Removal
1 - OVERDRIVE CLUTCH PISTON
2 - INTERMEDIATE SHAFT
3 - SELECTIVE SPACER
4 - PISTON RETAINER
Fig. 184 Overrunning Clutch
1 - OUTER RACE (CAM)
2 - ROLLER
3 - SPRING
4 - SPRING RETAINER
5 - INNER RACE (HUB)
DRAUTOMATIC TRANSMISSION - 48RE 21 - 415
OVERDRIVE UNIT (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

TRANSMISSION RANGE
SENSOR
DESCRIPTION
The Transmission Range Sensor (TRS) (Fig. 242)
has 3 primary functions:
²Provide a PARK/NEUTRAL start signal to the
engine controller and the starter relay.
²Turn the Back-up lamps on when the transmis-
sion is in REVERSE and the engine (ignition) is on.
²Provide a transmission range signal to the
instrument cluster.
The sensor is mounted in the transmission housing
near the valve body, just above the pan rail. It's in
the same position as the Park/Neutral switch on
other transmissions. The TRS contacts a cammed
surface on the manual valve lever. The cammed sur-
face translates the rotational motion of the manual
lever into the linear motion of the sensor. The
cammed surface on the manual lever is comprised of
two parts controlling the TRS signal: The insulator
portion contacts the switch poppet when the manual
lever is not in PARK or NEUTRAL. The manual
lever itself contacts the poppet when the lever is in
PARK or NEUTRAL; providing a ground for the sig-
nal from the starter relay and the JTEC engine con-
troller.
OPERATION
As the switch moves through its linear motion (Fig.
243) contacts slide across a circuit board which
changes the resistance between the range sensing
pins of the switch. A power supply on the instrument
cluster provides a regulated voltage signal to the
switch. The return signal is decoded by the cluster,
which then controls the PRNDL display to corre-
spond with the correct transmission range. A bus
message of transmission range is also sent by the
cluster. In REVERSE range a second contact set
closes the circuit providing power to the reverse
lamps.
Fig. 242 Transmission Range Sensor
Fig. 243 Transmission Range Sensor Linear
Movement
DRAUTOMATIC TRANSMISSION - 48RE 21 - 441

Mechanical State Electronic Display
(Ignition Unlocked)Electronic Display
(Ignition On)
Indicated Gear Position Transmission
StatusColumn Shifter
Position
P P P Vehicle is in PARK
with the pawl
engaged.In the PARK gate.
R The PARK pawl is
disengaged and the
vehicle is free to
roll, but REVERSE
is not engaged.Between the PARK
and REVERSE
gates.
R R R The transmission is
hydraulically in
REVERSE.In the REVERSE
gate.
N The transmission is
transitioning
between REVERSE
and NEUTRAL.Between the
REVERSE and
NEUTRAL gates.
N N N The vehicle is in
NEUTRAL.In the NEUTRAL
gate.
N The transmission is
transitioning
between NEUTRAL
and DRIVE, but is
not in DRIVE.Between the
NEUTRAL and
DRIVE gates.
D D D The transmission is
hydraulically in
DRIVE.In the DRIVE gate,
2 2 2 The transmission is
hydraulically in
Manual SECOND.In the SECOND
gate.
1 1 1 The transmission is
hydraulically in
Manual FIRST.In the FIRST gate.
DIAGNOSIS AND TESTING - TRANSMISSION
RANGE SENSOR (TRS)
NOTE: For all circuit identification in the following
steps, Refer to the appropriate Wiring Information.
(1) Raise vehicle on suitable hoist.
(2) Disconnect the vehicle's shift cable from the
manual lever.
(3) With the manual lever in the PARK position
(the PARK position is with the manual lever moved
to the full rearward position), measure the resistance
between the Park/Neutral Position Sense pin of the
TRS and the transmission case. The resistance
should be less than 5 ohms.(4) With the manual lever in the NEUTRAL posi-
tion (the NEUTRAL position is with the manual
lever moved two detents forward of the full rearward
position), measure the resistance between the Park/
Neutral Position Sense pin of the TRS and the trans-
mission case. The resistance should be less than 5
ohms.
(5) If the resistance is greater than 5 ohms in
either of the previous steps, check for a dirty contact
between the tip of the TRS rod and the valve body
manual lever. If the contact is OK, replace the TRS.
(6) With the manual lever in the REVERSE posi-
tion (the REVERSE position is with the manual lever
moved one detent forward of the full rearward posi-
tion), measure the resistance between the Fused
Ignition Switch Output and the Back-up Lamp feed
pins of the TRS. The resistance should be less than 5
21 - 442 AUTOMATIC TRANSMISSION - 48REDR
TRANSMISSION RANGE SENSOR (Continued)