1998 DODGE RAM 1500 Removal

(9) Mark annulus gear and output shaft for assem-
bly alignment reference (Fig. 144). Use punch or
scriber to mark gear and shaft.
(10) Remove snap-ring that secures annulus gear
on output shaft (Fig. 145). Use two screwdrivers to
unseat and work snap-ring out of groove as shown.
(11) Remove annulus gear from output shaft (Fig.
146). Use rawhide or plastic mallet to tap gear off
shaft.
GEAR CASE AND PARK LOCK
(1) Remove locating ring from gear case.
(2) Remove park pawl shaft retaining bolt and
remove shaft, pawl and spring.
(3) Remove reaction plug snap-ring and remove
reaction plug.
(4) Remove output shaft seal.
CLEANING
Clean the geartrain and case components with sol-
vent. Dry all parts except the bearings with com-
pressed air. Allow bearings to air dry.
Do not use shop towels for wiping parts dry unless
the towels are made from a lint-free material. A suf-
ficient quantity of lint (from shop towels, cloths, rags,
etc.) could plug the transmission filter and fluid pas-
sages.
Discard the old case gasket and seals. Do not
attempt to salvage these parts. They are not reus-
able. Replace any of the overdrive unit snap-rings if
distorted or damaged.
Minor nicks or scratches on components can be
smoothed with crocus cloth. However, do not attempt
to reduce severe scoring on any components with
abrasive materials. Replace severely scored compo-
nents; do not try to salvage them.
INSPECTION
Check condition of the park lock components and
the overdrive case.
Check the bushings in the overdrive case. Replace
the bushings if severely scored or worn. Also replace
the case seal if loose, distorted, or damaged.
Examine the overdrive and direct clutch discs and
plates. Replace the discs if the facing is worn,
severely scored, or burned and flaking off. Replace
the clutch plates if worn, heavily scored, or cracked.
Fig. 144 Marking Annulus Gear And Output Shaft
For Assembly Alignment
1 - OUTPUT SHAFT
2 - HAMMER
3 - PUNCH
Fig. 145 Annulus Gear Snap-Ring Removal
1 - OUTPUT SHAFT
2 - ANNULUS GEAR
3 - SNAP-RING
Fig. 146 Annulus Gear Removal
1 - OUTPUT SHAFT
2 - ANNULUS GEAR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 225
OVERDRIVE UNIT (Continued)

OVERRUNNING CLUTCH
CAM/OVERDRIVE PISTON
RETAINER
DESCRIPTION
The overrunning clutch (Fig. 178) 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. 179).
(2) Remove the overdrive piston retainer bolts.
(3) Remove overdrive piston retainer.
(4) Remove case gasket.(5) Tap old cam out of case with pin punch. Insert
punch through bolt holes at rear of case (Fig. 180).
Alternate position of punch to avoid cocking cam dur-
ing removal.
(6) Clean clutch cam bore and case. Be sure to
remove all chips/shavings generated during cam
removal.
CLEANING
Clean the overrunning clutch assembly, clutch cam,
low-reverse drum, and overdrive piston retainer in
solvent. Dry them with compressed air after clean-
ing.
Fig. 178 Overrunning Clutch
1 - OUTER RACE (CAM)
2 - ROLLER
3 - SPRING
4 - SPRING RETAINER
5 - INNER RACE (HUB)
Fig. 179 Overdrive Piston Removal
1 - OVERDRIVE CLUTCH PISTON
2 - INTERMEDIATE SHAFT
3 - SELECTIVE SPACER
4 - PISTON RETAINER
Fig. 180 Overrunning Clutch Cam
1 - PIN PUNCH
2 - REAR SUPPORT BOLT HOLES
21 - 236 AUTOMATIC TRANSMISSION - 48REDR

DISASSEMBLY
(1) Remove planetary snap-ring from intermediate
shaft (Fig. 193). Discard snap-ring as it is not reus-
able.
(2) Remove front planetary gear and front annulus
gear as assembly (Fig. 194).
(3) Remove front planetary gear and thrust
washer from front annulus gear (Fig. 195). Note
thrust washer position for assembly reference.
(4) Remove tabbed thrust washer from driving
shell (Fig. 196). Note washer position for assembly
reference.
Fig. 193 Removing Planetary Snap-Ring
1 - PLANETARY SNAP-RING
Fig. 194 Removing Front Planetary And Annulus
Gears
1 - DRIVING SHELL
2 - FRONT ANNULUS GEAR
3 - FRONT PLANETARY GEAR
Fig. 195 Disassembling Front Planetary And
Annulus Gears
1 - FRONT PLANETARY GEAR
2 - TABBED THRUST WASHER
3 - FRONT ANNULUS GEAR
4 - TORLON BUSHING
Fig. 196 Driving Shell Thrust Washer Removal
1 - DRIVING SHELL
2 - TABBED THRUST WASHER
3 - SUN GEAR
21 - 242 AUTOMATIC TRANSMISSION - 48REDR
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(5) Remove sun gear and driving shell as assembly
(Fig. 197).
(6) Remove tabbed thrust washer from rear plane-
tary gear (Fig. 198). Note washer position on gear for
assembly reference.
(7) Remove rear planetary gear and rear annulus
gear from intermediate shaft (Fig. 199).
(8) Remove thrust washer from rear planetary
gear (Fig. 200).
INSPECTION
Inspect the planetary gear sets and annulus gears.
The planetary pinions, shafts, washers, and retaining
pins are serviceable. However, if a pinion carrier is
damaged, the entire planetary gear set must be
replaced as an assembly.Replace the annulus gears if the teeth are chipped,
broken, or worn, or the gear is cracked. Replace the
planetary thrust plates and the tabbed thrust wash-
ers if cracked, scored or worn.
Inspect the machined surfaces of the intermediate
shaft. Be sure the oil passages are open and clear.
Replace the shaft if scored, pitted, or damaged.
Inspect the sun gear and driving shell. If either
component is worn or damaged, remove the sun gear
rear retaining ring and separate the sun gear and
thrust plate from the driving shell. Then replace the
necessary component.
Replace the sun gear as an assembly if the gear
teeth are chipped or worn. Also replace the gear as
an assembly if the bushings are scored or worn. The
sun gear bushings are not serviceable. Replace the
Fig. 197 Sun Gear And Driving Shell Removal
1 - INTERMEDIATE SHAFT
2 - DRIVING SHELL
3 - SUN GEAR
Fig. 198 Rear Planetary Thrust Washer Removal
1 - SUN GEAR
2 - REAR PLANETARY THRUST WASHER
3 - DRIVING SHELL
Fig. 199 Rear Planetary And Annulus Gear Removal
1 - INTERMEDIATE SHAFT
2 - REAR ANNULUS GEAR
3 - REAR PLANETARY GEAR
Fig. 200 Rear Annulus Thrust Washer Removal
1 - REAR ANNULUS GEAR
2 - THRUST WASHER
DRAUTOMATIC TRANSMISSION - 48RE 21 - 243
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft (Fig. 234).
Under stall conditions the turbine is stationary and
the oil leaving the turbine blades strikes the face of
the stator blades and tries to rotate them in a coun-
terclockwise direction. When this happens the over-
running 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
circulation of oil from impeller to turbine, turbine to
stator, and stator to impeller, can produce a maxi-
mum torque multiplication of about 1.75:1. 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)
The torque converter clutch is hydraulically
applied or released when fluid is feed or vented from
the hydraulic circuit by the torque converter control
(TCC) solenoid on the valve body. The torque con-
verter clutch is controlled by the Powertrain Control
Module (PCM). The torque converter clutch engages
in FOURTH gear, and in THIRD gear under various
conditions, such as when the O/D switch is OFF, orwhen the vehicle is cruising on a level surface after
the vehicle has warmed up. The torque converter
clutch can also be engaged in the MANUAL SEC-
OND gear position if high transmission temperatures
are sensed by the PCM. The torque converter clutch
may disengage momentarily when an increase in
engine load is sensed by the PCM, such as when the
vehicle begins to go uphill or the throttle pressure is
increased.
REMOVAL
(1) Remove transmission and torque converter
from vehicle.
(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 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.
Fig. 234 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
21 - 260 AUTOMATIC TRANSMISSION - 48REDR
TORQUE CONVERTER (Continued)

OPERATION
At key-on, overdrive operation is allowed. Pressing
the switch once causes the tow/haul overdrive OFF
mode to be entered and the Tow/Haul lamp to be illu-
minated. Pressing the switch a second time causes
normal overdrive operation to be restored and the
tow/haul lamp to be turned off. The tow/haul over-
drive OFF mode defaults to ON after the ignition
switch is cycled OFF and ON. The normal position
for the control switch is the ON position. The switch
must be in this position to energize the solenoid and
allow a 3-4 upshift. The control switch indicator light
illuminates only when the tow/haul overdrive switch
is turned to the OFF position, or when illuminated
by the transmission control module.
DIAGNOSIS AND TESTING - OVERDRIVE
ELECTRICAL CONTROLS
The tow/haul overdrive off switch, valve body sole-
noid, case connectors and related wiring can all be
tested with a 12 volt test lamp or a volt/ohmmeter.
Check continuity of each component when diagnosis
indicates this is necessary.
Switch and solenoid continuity should be checked
whenever the transmission fails to shift into fourth
gear range.
REMOVAL
(1) Using a plastic trim tool, remove the tow/haul
overdrive off switch retainer from the shift lever (Fig.
237).(2) Pull the switch outwards to release it from the
connector in the lever (Fig. 238)
INSTALLATION
NOTE: There is enough slack in the wire to pull out
the connector from the lever.
(1) Pull the connector out of the lever just enough
to grasp it.
CAUTION: Be careful not to bend the pins on the
tow/haul overdrive off switch. Use care when
installing the switch, as it is not indexed, and can
be accidentally installed incorrectly.
(2) Install the tow/haul overdrive off switch into
the connector (Fig. 239)
(3) Push the tow/haul overdrive off switch and wir-
ing into the shift lever.
(4) Install the tow/haul overdrive off switch
retainer onto the shift lever.
Fig. 237 Tow/Haul Overdrive Off Switch Retainer
Fig. 238 Remove the Tow/Haul Overdrive Off Switch
Fig. 239 Install the Tow/Haul Overdrive Off Switch
21 - 262 AUTOMATIC TRANSMISSION - 48REDR
TOW/HAUL OVERDRIVE SWITCH (Continued)

(7) 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 Transmission Range Sensor MUX and
the Transmission Range Sensor 5V Supply pins of
the TRS. The resistance should be 522.2 ohms. If the
resistance is not correct, replace the TRS.
(8) 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 Transmis-
sion Range Sensor MUX and the Transmission Range
Sensor 5V Supply pins of the TRS. The resistance
should be 206.2 ohms. If the resistance is not correct,
replace the TRS.
(9) 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 Trans-
mission Range Sensor MUX and the Transmission
Range Sensor 5V Supply pins of the TRS. The resis-
tance should be 108.6 ohms. If the resistance is not
correct, replace the TRS.
(10) With the manual lever in the DRIVE position
(the DRIVE position is with the manual lever moved
three detents forward of the full rearward position),
measure the resistance between the Transmission
Range Sensor MUX and the Transmission Range
Sensor 5V Supply pins of the TRS. The resistance
should be 59.9 ohms. If the resistance is not correct,
replace the TRS.
(11) With the manual lever in the SECOND posi-
tion (the SECOND position is with the manual lever
moved one detent rearward of the full forward posi-
tion), measure the resistance between the Transmis-
sion Range Sensor MUX and the Back-up Lamp feed
pins of the TRS. The resistance should be 31.9 ohms.
If the resistance is not correct, replace the TRS.
(12) With the manual lever in the LOW position
(the LOW position is with the manual lever moved to
the full forward position), measure the resistance
between the Transmission Range Sensor MUX and
the Back-up Lamp feed pins of the TRS. The resis-
tance should be 13.7 ohms. If the resistance is not
correct, replace the TRS.
REMOVAL
(1) Raise vehicle and position drain pan under the
transmission range sensor (TRS).
(2) Move the transmission manual lever to the
manual LOW position. The manual LOW position is
with the manual lever in the forward-most detent.(3) Disengage the wiring connector from the TRS.
(4) Remove the two screws holding the TRS to the
TRS mounting bracket.
(5) Remove the TRS (Fig. 242) from the TRS
mounting bracket by pulling it straight out of the
bracket.
(6) Loosen the TRS mounting bracket in the trans-
mission case using Adapter 8581 (Fig. 243).
Fig. 242 Remove Transmission Range Sensor
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
3 - TRANSMISSION RANGE SENSOR
Fig. 243 Loosen the TRS Mounting Bracket
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
3 - ADAPTER 8581
DRAUTOMATIC TRANSMISSION - 48RE 21 - 265
TRANSMISSION RANGE SENSOR (Continued)

BOOST VALVE
The boost valve (Fig. 271) provides increased fluid
apply pressure to the overdrive clutch during 3-4
upshifts (Fig. 272), and when accelerating in fourth
gear. The boost valve also serves to increase line
pressure during torque converter lock-up.
REMOVAL
The valve body can be removed for service without
having to remove the transmission assembly.
The valve body can be disassembled for cleaning
and inspection of the individual components.
The only replaceable valve body components are:
²Manual lever.
²Manual lever washer, seal, E-clip, and shaft
seal.
²Manual lever detent ball.
²Throttle lever.
²Fluid filter.
²Pressure adjusting screw bracket.
²Governor pressure solenoid.
²Governor pressure sensor (includes transmission
temperature thermistor).
²Converter clutch/overdrive solenoid assembly
and harness.
²Governor housing gasket.
²Solenoid case connector O-rings.
(1) Shift transmission into NEUTRAL.
(2) Raise vehicle.
(3) Remove gearshift and throttle levers from shaft
of valve body manual lever.
(4) Disconnect wires at solenoid case connector
(Fig. 273).
(5) Remove the transmission range sensor (Refer
to 21 - TRANSMISSION/AUTOMATIC/TRANSMIS-
SION RANGE SENSOR - REMOVAL).
(6) Position drain pan under transmission oil pan.
(7) Remove transmission oil pan and gasket.
(8) Remove fluid filter from valve body.
(9) Remove bolts attaching valve body to transmis-
sion case.
(10) Lower valve body enough to remove accumu-
lator piston and springs.
Fig. 273 Transmission Case Connector
1 - SOLENOID CASE CONNECTOR
2 - TRANSMISSION RANGE SENSOR
Fig. 271 Boost Valve Before Lock-up
Fig. 272 Boost Valve After Lock-up
21 - 286 AUTOMATIC TRANSMISSION - 48REDR
VALVE BODY (Continued)