1998 DODGE RAM 1500 Transmission install

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) Remove the TRS mounting bracket (Fig. 244)
from the transmission case.
INSTALLATION
(1) Move the transmission manual shaft lever to
the manual LOW position.
(2) Install the TRS mounting bracket into the
transmission case. Using Adapter 8581 (Fig. 245),
tighten the mounting bracket to 34 N´m (300 in.lbs.).(3) Install the TRS (Fig. 246) into the mounting
bracket with the wiring connector facing the front of
the transmission.
(4) Install the two screws to hold the TRS to the
mounting bracket. Tighten the screws to 5 N´m (45
in.lbs.).
(5) Verify proper sensor operation (Fig. 247).
(6) Move the transmission manual shaft lever to
the PARK position.
(7) Connect TRS wiring connector to the TRS and
lower vehicle.
(8) Refill the transmission fluid to the correct
level.
Fig. 244 Remove TRS Mounting Bracket
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
Fig. 245 Tighten the TRS Mounting Bracket
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
3 - ADAPTER 8581
Fig. 246 Remove Transmission Range Sensor
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
3 - TRANSMISSION RANGE SENSOR
Fig. 247 Transmission Range Sensor Operation
1 - NEUTRAL CONTACT
2 - MANUAL LEVER AND SENSOR PLUNGER IN REVERSE
POSITION
3 - PARK CONTACT
4 - TRANSMISSION RANGE SENSOR
21 - 266 AUTOMATIC TRANSMISSION - 48REDR
TRANSMISSION RANGE SENSOR (Continued)

(11) Work manual lever shaft and electrical con-
nector out of transmission case.
(12) Lower valve body, rotate valve body away
from case, pull park rod out of sprag, and remove
valve body (Fig. 274).
DISASSEMBLY
CAUTION: Do not clamp any valve body component
in a vise. This practice can damage the component
resulting in unsatisfactory operation after assembly
and installation. Do not use pliers to remove any of
the valves, plugs or springs and do not force any of
the components out or into place. The valves and
valve body housings will be damaged if force is
used. Tag or mark the valve body springs for refer-
ence as they are removed. Do not allow them to
become intermixed.
(1) Disconnect wires from governor pressure sen-
sor and solenoid.
(2) Remove screws attaching governor body and
retainer plate to transfer plate.
(3) Remove retainer plate, governor body and gas-
ket from transfer plate.(4) Remove governor pressure sensor from gover-
nor body.
(5) Remove governor pressure solenoid by pulling
it straight out of bore in governor body. Remove and
discard solenoid O-rings if worn, cut, or torn.
(6) Remove small shoulder bolt that secures sole-
noid harness case connector to 3-4 accumulator hous-
ing (Fig. 275). Retain shoulder bolt. Either tape it to
harness or thread it back into accumulator housing
after connector removal.
(7) Unhook overdrive/converter solenoid harness
from 3-4 accumulator cover plate (Fig. 276).
Fig. 275 Solenoid Harness Case Connector
Shoulder Bolt
1 - SOLENOID HARNESS CASE CONNECTOR
2 - 3-4 ACCUMULATOR HOUSING
Fig. 276 Solenoid Harness Routing
1 - OVERDRIVE/CONVERTER SOLENOID WIRE HARNESS
2 - 3-4 ACCUMULATOR COVER PLATE
Fig. 274 Valve Body
1 - VALVE BODY
2 - WIRE HARNESS
3 - PARK ROD
4 - GOVERNOR PRESSURE SOLENOID
5 - GOVERNOR PRESSURE SENSOR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 287
VALVE BODY (Continued)

Check the two separator plates for distortion or
damage of any kind. Inspect the upper housing,
lower housing, 3-4 accumulator housing, and transfer
plate carefully. Be sure all fluid passages are clean
and clear. Check condition of the upper housing and
transfer plate check balls as well. The check balls
and ball seats must not be worn or damaged.
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.
The only serviceable valve body components are
listed below. The remaining valve body components
are serviced only as part of a complete valve body
assembly. Serviceable parts are:
²dual solenoid and harness assembly
²solenoid gasket
²solenoid case connector O-rings and shoulder
bolt
²switch valve and spring
²pressure adjusting screw and bracket assembly
²throttle lever
²manual lever and shaft seal
²throttle lever shaft seal, washer, and E-clip
²fluid filter and screws
²detent ball and spring
²valve body screws
²governor pressure solenoid
²governor pressure sensor and retaining clip
²park lock rod and E-clipASSEMBLY
CAUTION: Do not force valves or plugs into place
during reassembly. If the valve body bores, valves
and plugs are free of distortion or burrs, the valve
body components should all slide into place easily.
In addition, do not overtighten the transfer plate
and valve body screws during reassembly. Over-
tightening can distort the housings resulting in
valve sticking, cross leakage and unsatisfactory
operation. Tighten valve body screws to recom-
mended torque only.
LOWER HOUSING
(1) Lubricate valves, springs, and the housing
valve and plug bores with clean transmission fluid
(Fig. 305).
(2) Install 3-4 timing valve spring and valve in
lower housing.
(3) Install 3-4 quick fill valve in lower housing.
(4) Install 3-4 quick fill valve spring and plug in
housing.
(5) Install timing valve end plate. Tighten end
plate screws to 4 N´m (35 in. lbs.) torque.
DRAUTOMATIC TRANSMISSION - 48RE 21 - 299
VALVE BODY (Continued)

3-4 ACCUMULATOR
(1) Lubricate accumulator piston, seals and hous-
ing piston bore with clean transmission fluid (Fig.
306).
(2) Install new seal rings on accumulator piston.
(3) Install piston and spring in housing.
(4) Install end plate on housing.
TRANSFER PLATE
(1) Install rear clutch and rear servo check balls in
transfer plate (Fig. 307).
(2) Install filter screen in upper housing separator
plate (Fig. 308).
(3) Align and position upper housing separator
plate on transfer plate (Fig. 309).
(4) Install brace plate (Fig. 309). Tighten brace
attaching screws to 4 N´m (35 in. lbs.) torque.
(5) Install remaining separator plate attaching
screws. Tighten screws to 4 N´m (35 in. lbs.) torque.
Fig. 306 3-4 Accumulator and Housing
1 - ACCUMULATOR PISTON
2 - 3-4 ACCUMULATOR HOUSING
3 - TEFLON SEALS
4 - PISTON SPRING
5 - COVER PLATE AND SCREWS
Fig. 307 Rear Clutch And Rear Servo Check Ball
Locations
1 - REAR CLUTCH CHECK BALL
2 - REAR SERVO CHECK BALL
3 - TRANSFER PLATE
Fig. 308 Separator Plate Filter Screen Installation
1 - UPPER HOUSING SEPARATOR PLATE
2 - FILTER SCREEN
Fig. 309 Brace Plate
1 - BRACE
2 - TRANSFER PLATE
3 - SEPARATOR PLATE
DRAUTOMATIC TRANSMISSION - 48RE 21 - 301
VALVE BODY (Continued)

UPPER AND LOWER HOUSING
(1) Position upper housing so internal passages
and check ball seats are facing upward. Then install
check balls in housing (Fig. 310). Seven check balls
are used. The single large check ball is approxi-
mately 8.7 mm (11/32 in.) diameter. The single small
check ball is approximately 4.8 mm (3/16 in.) in
diameter. The remaining 5 check balls are approxi-
mately 6.3 mm (1/4 in.) in diameter.
(2) Position assembled transfer plate and upper
housing separator plate on upper housing (Fig. 311).
Be sure filter screen is seated in proper housing
recess.(3) Install the Number 10 check ball into the
transfer plate (Fig. 312). The check ball is approxi-
mately 4.8 mm (3/16 in.) in diameter.
(4) Position lower housing separator plate on
transfer plate (Fig. 313).
Fig. 310 Check Ball Locations In Upper Housing
1 - SMALL DIAMETER CHECK BALLS (5)
2 - LARGE DIAMETER CHECK BALL (1)
Fig. 311 Installing Transfer Plate On Upper Housing
1 - FILTER SCREEN
2 - TRANSFER PLATE/SEPARATOR PLATE ASSEMBLY
3 - UPPER HOUSING
Fig. 312 Number 10 Check Ball
1 - NUMBER 10 CHECK BALL (3/169)
Fig. 313 Lower Housing Separator Plate
1 - BE SURE TO ALIGN BORES
2 - TRANSFER PLATE
3 - LOWER HOUSING (OVERDRIVE) SEPARATOR PLATE
21 - 302 AUTOMATIC TRANSMISSION - 48REDR
VALVE BODY (Continued)

(5) Install lower housing on assembled transfer
plate and upper housing (Fig. 314).
(6) Install and start all valve body screws by hand
except for the screws to hold the boost valve tube
brace. Save those screws for later installation. Then
tighten screws evenly to 4 N´m (35 in. lbs.) torque.
Start at center and work out to sides when tighten-
ing screws (Fig. 314).
UPPER HOUSING VALVE AND PLUG
Refer to (Fig. 315), (Fig. 316) and (Fig. 317) to per-
form the following steps.
(1) Lubricate valves, plugs, springs with clean
transmission fluid.
(2) Assemble regulator valve line pressure sleeve,
throttle plug and spring. Insert assembly in upper
housing and install cover plate. Tighten cover plate
screws to 4 N´m (35 in. lbs.) torque.
(3) Install 1-2 and 2-3 shift valves and springs.
(4) Install 1-2 shift control valve and spring.
Fig. 314 Installing Lower Housing On Transfer Plate
And Upper Housing
1 - VALVE BODY SCREWS (13)
2 - LOWER HOUSING
3 - UPPER HOUSING
4 - TRANSFER PLATE
Fig. 315 Shuttle and Boost Valve Locations
1 - SPRING 8 - SHUTTLE VALVE COVER
2 - RETAINER 9 - SHUTTLE VALVE
3 - BOOST VALVE 10 - SHUTTLE VALVE PRIMARY SPRING
4 - BOOST VALVE PLUG 11 - GOVERNOR PLUG COVER
5 - SPRING GUIDES 12 - THROTTLE PLUG
6 - E-CLIP 13 - UPPER HOUSING
7 - SHUTTLE VALVE SECONDARY SPRING 14 - BOOST VALVE COVER
DRAUTOMATIC TRANSMISSION - 48RE 21 - 303
VALVE BODY (Continued)

(5) Install retainer, spring, limit valve, and 2-3
throttle plug from limit valve housing.
(6) Install limit valve housing and cover plate.
Tighten screws to 4 N´m (35 in. lbs.).
(7) Install shuttle valve as follows:
(a) Insert plastic guides in shuttle valve second-
ary spring and install spring on end of valve.
(b) Install shuttle valve into housing.
(c) Hold shuttle valve in place.
(d) Compress secondary spring and install E-clip
in groove at end of shuttle valve.(e) Verify that spring and E-clip are properly
seated before proceeding.
(8) Install shuttle valve cover plate. Tighten cover
plate screws to 4 N´m (35 in. lbs.) torque.
(9) Install 1-2 and 2-3 valve governor plugs in
valve body.
(10) Install shuttle valve primary spring and
throttle plug.
(11) Align and install governor plug cover. Tighten
cover screws to 4 N´m (35 in. lbs.) torque.
Fig. 316 Upper Housing Control Valve Locations
1 - UPPER HOUSING 8 - MANUAL VALVE
2 - REGULATOR VALVE 9 - 1-2 GOVERNOR PLUG
3 - SWITCH VALVE 10 - GOVERNOR PLUG COVER
4 - REGULATOR VALVE SPRING 11 - THROTTLE PLUG
5 - KICKDOWN VALVE 12 - 2-3 GOVERNOR PLUG
6 - KICKDOWN DETENT 13 - SHUTTLE VALVE PRIMARY SPRING
7 - THROTTLE VALVE AND SPRING
21 - 304 AUTOMATIC TRANSMISSION - 48REDR
VALVE BODY (Continued)