1998 DODGE RAM 1500 one

(4) Check seal rings on reaction shaft support. Be
sure rings are hooked together correctly. Also be sure
fiber thrust washer is in position (Fig. 55). Use extra
petroleum jelly to hold washer in place if necessary.
(5) Check the torque converter hub seal ring on
the reaction shaft for damage. Also check that the
seal ring rotates freely in the reaction shaft groove.
Replace the seal if necessary.
(6) Lubricate oil pump seals with petroleum
MopartATF +4.
(7) Mount oil pump on pilot studs and slide pump
into case opening (Fig. 56).Work pump into case
by hand. Do not use a mallet or similar tools to
seat pump.
(8) Remove pilot studs and install oil pump bolts.
Tighten pump bolts alternately and evenly to fully
seat pump in case. Then final-tighten pump bolts to
20 N´m (15 ft. lbs.) torque.
(9) Verify correct installation. Rotate input and
intermediate shafts and check for bind. If bind exists,
components are either mis-assembled, or not seated.
Disassemble and correct as necessary before proceed-
ing.
INPUT SHAFT END PLAY CHECK
NOTE: Overdrive unit must be installed in order to
correctly measure the input shaft end-play.
(1) Measure input shaft end play (Fig. 57).NOTE: If end play is incorrect, transmission is
incorrectly assembled, or reaction shaft thrust
washer is incorrect. The reaction shaft thrust
washer is selective.
(a) Attach Adapter 8266-5 to Handle 8266-8.
(b) Attach dial indicator C-3339 to Handle
8266-8.
(c) Install the assembled tool onto the input
shaft of the transmission and tighten the retaining
screw on Adapter 8266-5 to secure it to the input
shaft.
(d) Position the dial indicator plunger against a
flat spot on the oil pump and zero the dial indica-
tor.
(e) Move input shaft in and out and record read-
ing. End play should be 0.86 - 2.13 mm (0.034 -
0.084 in.). Adjust as necessary.
ACCUMULATOR, VALVE BODY, OIL PAN, AND
TORQUE CONVERTER
(1) Install accumulator inner spring, piston and
outer spring (Fig. 58).
(2) Verify that the transmission range sensor has
notbeen installed in case. Valve body can not be
installed if sensor is in position.
(3) Install new valve body manual shaft seal in
case (Fig. 59). Lubricate seal lip and manual shaft
with petroleum jelly. Start seal over shaft and into
case. Seat seal with 15/16 inch, deep well socket.
(4) Install valve body as follows:Fig. 56 Oil Pump
1 - SEAT OIL PUMP IN CASE BY HAND
2 - REMOVE PILOT STUDS WHEN PUMP IS SEATED
Fig. 57 Checking Input Shaft End Play
1 - TOOL 8266-8
2 - TOOL 8266-5
3 - TOOL C-3339
21 - 172 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

(a) Start park rod into park pawl. If rod will not
slide past park pawl, pawl is engaged in park gear.
Rotate overdrive output shaft with suitable size 12
point socket; this will free pawl and allow rod to
engage.
(b) Align and seat valve body on case. Be sure
manual lever shaft and overdrive connector are
fully seated in case.
(c) Install and start all valve body attaching
bolts by hand. Then tighten bolts evenly, in a diag-
onal pattern to 12 N´m (105 in. lbs.) torque.Do
not overtighten valve body bolts. This could
result in distortion and cross leakage after
installation..
(5) Install new filter on valve body. Tighten filter
screws to 4 N´m (35 in. lbs.).
CAUTION: If the condition of the transmission
before the overhaul procedure caused excessive
metallic or fiber contamination in the fluid, replace
the torque converter and reverse flush the cooler(s)
and cooler lines. Fluid contamination and transmis-
sion failure can result if not done.(6) Move the transmission manual shaft lever to
the manual LOW position.
(7) Install the TRS mounting bracket into the
transmission case. Using Adapter 8581 (Fig. 60),
tighten the mounting bracket to 34 N´m (300 in.lbs.).
(8) Install the TRS (Fig. 61) into the mounting
bracket with the wiring connector facing the front of
the transmission.
Fig. 58 Accumulator Piston And Springs
1 - ACCUMULATOR PISTON
2 - OUTER SPRING
3 - INNER SPRING
Fig. 59 Manual Lever Shaft Seal
1 - 15/1688SOCKET
2 - SEAL
Fig. 60 Tighten the TRS Mounting Bracket
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
3 - ADAPTER 8581
Fig. 61 Remove Transmission Range Sensor
1 - SOLENOID CASE CONNECTOR
2 - TRS MOUNTING BRACKET
3 - TRANSMISSION RANGE SENSOR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 173
AUTOMATIC TRANSMISSION - 48RE (Continued)

(13) Install bolts attaching converter housing to
engine.
(14) Install rear support.
(15) Install the rear transmission crossmember.
(16) Lower transmission onto crossmember and
install bolts attaching transmission mount to cross-
member.
(17) Remove engine support fixture.
(18) Install the transfer case, if equipped.
(19) Install crankshaft position sensor. (Refer to 14
- FUEL SYSTEM/FUEL INJECTION/CRANKSHAFT
POSITION SENSOR - INSTALLATION)
(20) Connect gearshift cable (Fig. 64) and throttle
cable to transmission.
(21) Connect wires to the transmission range sen-
sor and transmission solenoid connector. Be sure the
transmission harnesses are properly routed.
CAUTION: It is essential that correct length bolts be
used to attach the converter to the driveplate. Bolts
that are too long will damage the clutch surface
inside the converter.(22) Install torque converter-to-driveplate bolts.
(23) Install converter housing access cover.
(24) Install starter motor and cooler line bracket.
(Refer to 8 - ELECTRICAL/STARTING/STARTER
MOTOR - INSTALLATION)
(25) Connect cooler lines (Fig. 65) to transmission.
(26) Install transmission fill tube. Install new seal
on tube before installation.
(27) Install any exhaust components previously
removed.
(28) Align and connect propeller shaft. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/PROPELLER
SHAFT/PROPELLER SHAFT - INSTALLATION)
(29) Adjust gearshift cable and throttle valve
cable, if necessary.
(30) Install the transfer case skid plate, if
equipped.
(31) Lower vehicle.
(32) Fill transmission with MopartATF +4, Auto-
matic Transmission fluid.
Fig. 64 Gearshift Cable At Transmission
1 - GEARSHIFT CABLE
2 - TRANSMISSION MANUAL LEVER
3 - CABLE SUPPORT BRACKET
Fig. 65 Transmission Cooler Lines
1 - TRANSMISSION
2 - RADIATOR
3 - COOLER LINES
DRAUTOMATIC TRANSMISSION - 48RE 21 - 175
AUTOMATIC TRANSMISSION - 48RE (Continued)

SPECIFICATIONS
TRANSMISSION
GENERAL
Component Metric Inch
Planetary end play 0.150-1.22
mm0.006-0.048
in.
Input shaft end play 0.86-2.13
mm0.034-0.084
in.
Clutch pack clearance/
Front.2.5-4.09
mm0.098-0.161
in.
Clutch pack clearance/
Rear.0.635-0.914
mm0.025-0.036
in.
Front clutch 5 discs
Rear clutch 4 discs
Overdrive clutch 5(STD) OR 6(Diesel HO)
discs
Direct clutch 23 Single Sided discs
Band adjustment from
72 in. lbs.
Front band Back off 1 3/4 turns
Rear band Back off 3 turns
Recommended fluid MoparTAT F + 4GEAR RATIOS
1ST GEAR 2.45:1
2ND GEAR 1.45:1
3RD GEAR 1.0:1
4TH GEAR 0.69:1
REVERSE 2.20:1
THRUST WASHER/SPACER/SNAP-RING DIMENSIONS
Component Metric Inch
Front clutch thrust washer (reaction shaft support hub) 1.55 mm 0.061 in.
2.15 mm 0.084 in.
2.59 mm 0.102 in.
Rear clutch thrust washer (clutch retainer) 1.55 mm 0.061 in.
Intermediate shaft thrust plate (shaft hub pilot) 1.5-1.6 mm 0.060-0.063 in.
Output shaft thrust washer (rear clutch hub) 1.3-1.4 mm 0.052-0.054 in.
1.75-1.8 mm 0.068-0.070 in.
2.1-2.2 mm 0.083-0.085 in.
Rear clutch pack snap-ring 1.5-1.6 mm 0.060-0.062 in.
1.9-1.95 mm 0.074-0.076 in.
Planetary geartrain snap-ring (at front of output shaft) 1.4-1.5 mm 0.055-0.059 in.
1.6-1.7 mm 0.062-0.066 in.
Overdrive piston thrust plate Thrust plate and
spacer are select fit.
Refer to size charts
and selection
procedures in
Overdrive Unit D&A
procedures Intermediate shaft spacer
DRAUTOMATIC TRANSMISSION - 48RE 21 - 189
AUTOMATIC TRANSMISSION - 48RE (Continued)

ACCUMULATOR
DESCRIPTION
The accumulator (Fig. 66) is a hydraulic device
that has the sole purpose of cushioning the applica-
tion of a band or clutch. The accumulator consists of
a dual-land piston and a spring located in a bore in
the transmission case. The 3-4 accumulator is located
in a housing attached to the side of the valve body
(Fig. 67).
OPERATION
Both the accumulator and the 3-4 accumulator
function the same. Line pressure is directed to the
small end of the piston when the transmission is
placed into a DRIVE position (Fig. 68), bottoming it
against the accumulator plate. When the 1-2 upshift
occurs (Fig. 69), line pressure is directed to the large
end of the piston and then to the kickdown servo. As
the line pressure reaches the accumulator, the com-
bination of spring pressure and line pressure forces
the piston away from the accumulator plate. This
causes a balanced pressure situation, which results
in a cushioned band application. After the kickdown
servo has become immovable, line pressure will fin-
ish pushing the accumulator up into its bore. When
the large end of the accumulator piston is seated in
its bore, the band or clutch is fully applied.
NOTE: The accumulator is shown in the inverted
position for illustrative purposes.
Fig. 66 Accumulator
1 - ACCUMULATOR PISTON
2 - PISTON SPRING
Fig. 67 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. 68 Accumulator in DRIVE - FIRST Gear Position
1 - LINE PRESSURE
DRAUTOMATIC TRANSMISSION - 48RE 21 - 193

INSPECTION
Inspect the accumulator piston and seal rings.
Replace the seal rings if worn or cut. Replace the pis-
ton if chipped or cracked.
Check condition of the accumulator inner and
outer springs. Replace the springs if the coils are
cracked, distorted or collapsed.
BANDS
DESCRIPTION
KICKDOWN (FRONT) BAND
The kickdown, or ªfrontº, band (Fig. 70) holds the
common sun gear of the planetary gear sets. The
front (kickdown) band is made of steel, and faced on
its inner circumference with a friction-type lining.
One end of the band is anchored to the transmission
case, and the other is acted on with a pushing force
by a servo piston. The front band is a single-wrap
design (the band does not completely encompass/
wrap the drum that it holds).
LOW/REVERSE (REAR) BAND
The low/reverse band, or ªrearº, band (Fig. 71) is
similar in appearance and operation to the front
band. The rear band is slightly different in that it
does not use a link bar, but is acted directly on by
the apply lever. This is referred to as a double-wrapband design (the drum is completely encompassed/
wrapped by the band). The double-wrap band pro-
vides a greater holding power in comparison to the
single-wrap design.
OPERATION
KICKDOWN (FRONT) BAND
The kickdown band holds the common sun gear of
the planetary gear sets by applying and holding the
front clutch retainer, which is splined to the sun gear
driving shell, and in turn splined directly to the sun
gear. The application of the band by the servo is typ-
ically done by an apply lever and link bar.
Fig. 69 Accumulator in SECOND Gear Position
1 - BOTTOM OF BORE
2 - LINE PRESSURE
3 - SHUTTLE VALVE
Fig. 70 Front Band
1 - FRONT BAND
2 - TRANSMISSION HOUSING
Fig. 71 Rear Band
1 - ADJUSTING SCREW
2 - LOCKNUT
3 - LEVER
4 - REAR BAND
5 - REACTION PIN
6 - O-RINGS
7 - PIVOT PIN
21 - 194 AUTOMATIC TRANSMISSION - 48REDR
ACCUMULATOR (Continued)

BRAKE TRANSMISSION SHIFT
INTERLOCK SYSTEM
DESCRIPTION
The Brake Transmission Shifter Interlock (BTSI)
(Fig. 74), is a solenoid operated system. It consists of
a solenoid permanently mounted on the gearshift
cable.
OPERATION
The system locks the shifter into the PARK posi-
tion. The interlock system is engaged whenever the
ignition switch is in the LOCK or ACCESSORY posi-
tion. An additional electrically activated feature will
prevent shifting out of the PARK position unless the
brake pedal is depressed approximately one-half an
inch. A magnetic holding device in line with the park
lock cable is energized when the ignition is in the
RUN position. When the key is in the RUN position
and the brake pedal is depressed, the shifter is
unlocked and will move into any position. The inter-
lock system also prevents the ignition switch from
being turned to the LOCK or ACCESSORY position,
unless the shifter is fully locked into the PARK posi-
tion.
DIAGNOSIS AND TESTING - BRAKE
TRANSMISSION SHIFT INTERLOCK
(1) Verify that the key can only be removed in the
PARK position
(2) When the shift lever is in PARK And the shift
handle pushbutton is in the ªOUTº position, the igni-
tion key cylinder should rotate freely from OFF toLOCK. When the shifter is in any other gear or neu-
tral position, the ignition key cylinder should not
rotate to the LOCK position.
(3) Shifting out of PARK should not be possible
when the ignition key cylinder is in the OFF posi-
tion.
(4) Shifting out of PARK should not be possible
while applying normal pushbutton force and ignition
key cylinder is in the RUN or START positions
unless the foot brake pedal is depressed approxi-
mately 1/2 inch (12mm).
(5) Shifting out of PARK should not be possible
when the ignition key cylinder is in the ACCESSORY
or LOCK positions.
(6) Shifting between any gears, NEUTRAL or into
PARK may be done without depressing foot brake
pedal with ignition switch in RUN or START posi-
tions.
ADJUSTMENTS - BRAKE TRANSMISSION
SHIFT INTERLOCK
Correct cable adjustment is important to proper
interlock operation. The gearshift cable must be cor-
rectly adjusted in order to shift out of PARK.
ADJUSTMENT PROCEDURE
(1) Remove the steering column trim as necessary
for access to the brake transmission shift interlock.
(2) Shift the transmission into the PARK position.
(3) Pull upward on both the BTSI lock tab and the
gearshift cable lock tab (Fig. 75).
(4) Verify that the shift lever is in the PARK posi-
tion.
(5) Verify positive engagement of the transmission
park lock by attempting to rotate the propeller shaft.
The shaft will not rotate when the park lock is
engaged.
(6) Turn ignition switch to LOCK position.Be
sure ignition key cylinder is in the LOCK posi-
tion. Cable will not adjust correctly in any
other position.
(7) Ensure that the cable is free to self-adjust by
pushing cable rearward and releasing.
(8) Push the gearshift cable lock tab down until it
snaps in place.
(9) Locate the BTSI alignment hole in the bottom
of the BTSI mechanism between the BTSI lock tab
and the BTSI connector.
(10) Move the BTSI assembly up or down on the
gearshift cable until an appropriate size drill bit can
be inserted into the alignment hole and through the
assembly.
(11) Push the BTSI lock tab down until it snaps
into place and remove the drill bit.
(12) Install any steering column trim previously
removed.
Fig. 74 Brake Transmission Interlock Mechanism
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
21 - 196 AUTOMATIC TRANSMISSION - 48REDR

BTSI FUNCTION CHECK
(1) Verify removal of ignition key allowed in PARK
position only.
(2) When the shift lever is in PARK, the ignition
key cylinder should rotate freely from off to lock.
When the shifter is in any other position, the ignition
key should not rotate from off to lock.
(3) Shifting out of PARK should be possible when
the ignition key cylinder is in the off position.
(4) Shifting out of PARK should not be possible
while applying normal force, and ignition key cylin-
der is in the run or start positions, unless the foot
brake pedal is depressed approximately 1/2 inch
(12mm).
(5) Shifting out of PARK should not be possible
when the ignition key cylinder is in the accessory or
lock position.
(6) Shifting between any gear and NEUTRAL, or
PARK, may be done without depressing foot brake
with ignition switch in run or start positions.
(7) Engine starts must be possible with shifter
lever in PARK or NEUTRAL positions only. Engine
starts must not be possible in any position other than
PARK or NEUTRAL.
(8) With shifter lever in the:
²PARK position - Apply upward force on the shift
arm and remove pressure. Engine starts must be
possible.²PARK position - Apply downward force on the
shift arm and remove pressure. Engine starts must
be possible.
²NEUTRAL position - Normal position. Engine
starts must be possible.
²NEUTRAL position - Engine running and brakes
applied, apply upward force on the shift arm. Trans-
mission shall not be able to shift from neutral to
reverse.
ELECTRONIC GOVERNOR
DESCRIPTION
Governor pressure is controlled electronically. Com-
ponents used for governor pressure control include:
²Governor body
²Valve body transfer plate
²Governor pressure solenoid valve
²Governor pressure sensor
²Fluid temperature thermistor
²Throttle position sensor (TPS)
²Transmission speed sensor
²Powertrain control module (PCM)
GOVERNOR PRESSURE SOLENOID VALVE
The solenoid valve is a duty-cycle solenoid which
regulates the governor pressure needed for upshifts
and downshifts. It is an electro-hydraulic device
located in the governor body on the valve body trans-
fer plate (Fig. 76).
Fig. 75 Brake Transmission Interlock Mechanism
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
Fig. 76 Governor Pressure Solenoid Valve
1 - SOLENOID FILTER
2 - GOVERNOR PRESSURE SOLENOID
DRAUTOMATIC TRANSMISSION - 48RE 21 - 197
BRAKE TRANSMISSION SHIFT INTERLOCK SYSTEM (Continued)