1998 DODGE RAM 1500 Reverse

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)

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)

LOW/REVERSE (REAR) BAND
The rear band holds the rear planet carrier sta-
tionary by being mounted around and applied to the
low/reverse drum.
ADJUSTMENTS
ADJUSTMENT - BANDS
FRONT BAND
The front (kickdown) band adjusting screw is
located on the left side of the transmission case
above the manual valve and throttle valve levers.
(1) Raise vehicle.
(2) Loosen band adjusting screw locknut (Fig. 72).
Then back locknut off 3-5 turns. Be sure adjusting
screw turns freely in case. Apply lubricant to screw
threads if necessary.
(3) Tighten band adjusting screw to 8 N´m (72 in.
lbs.) torque with an appropriate TorxŸ socket.
CAUTION: If Adapter C-3705 is needed to reach the
adjusting screw, tighten the screw to only 5 N´m
(47-50 in. lbs.) torque.
(4) Back off front band adjusting screw 1-3/4
turns.
(5) Hold adjuster screw in position and tighten
locknut to 41 N´m (30 ft. lbs.) torque.
(6) Lower vehicle.
REAR BAND
The transmission oil pan must be removed for
access to the rear band adjusting screw.
(1) Raise vehicle.
(2) Remove transmission oil pan and drain fluid.
(3) Loosen band adjusting screw locknut 5-6 turns.
Be sure adjusting screw turns freely in lever.
(4) Tighten adjusting screw to 8 N´m (72 in. lbs.)
torque (Fig. 73).
(5) Back off adjusting screw 3 turns.
(6) Hold adjusting screw in place and tighten lock-
nut to 34 N´m (25 ft. lbs.) torque.
(7) Position new gasket on oil pan and install pan
on transmission. Tighten pan bolts to 17 N´m (13 ft.
lbs.) torque.
(8) Lower vehicle and refill transmission with
MopartATF +4, Automatic Transmission fluid.
Fig. 72 Front Band Adjustment Screw Location
1 - LOCK-NUT
2 - FRONT BAND ADJUSTER
Fig. 73 Rear Band Adjustment Screw Location
1 - LOW-REVERSE BAND ADJUSTMENT
DRAUTOMATIC TRANSMISSION - 48RE 21 - 195
BANDS (Continued)

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)

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. 88).
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.
STANDARD PROCEDURE - FLUID AND FILTER
REPLACEMENT
For proper service intervals (Refer to LUBRICA-
TION & MAINTENANCE/MAINTENANCE SCHED-
ULES - DESCRIPTION). The service fluid fill after a
filter change is approximately 3.8 liters (4.0 quarts).
REMOVAL
(1) Hoist and support vehicle on safety stands.
(2) Place a large diameter shallow drain pan
beneath the transmission pan.
(3) Remove bolts holding front and sides of pan to
transmission (Fig. 89).
(4) Loosen bolts holding rear of pan to transmis-
sion.
Fig. 88 48RE Fluid Fill Graph
Fig. 89 Transmission Pan
1 - TRANSMISSION
2 - REUSABLE GASKET
3-PAN
DRAUTOMATIC TRANSMISSION - 48RE 21 - 203
FLUID AND FILTER (Continued)

(2) Install rod in piston. Install spring and washer
on rod. Compress spring and install snap-ring (Fig.
101).
GEARSHIFT CABLE
DIAGNOSIS AND TESTING - GEARSHIFT
CABLE
(1) Engine starts must be possible with shift lever
in PARK or NEUTRAL positions only. Engine starts
must not be possible in any other gear position.
(2) With the shift lever in the:
(a) PARK position - Apply upward force on the
shift arm and remove pressure. Engine starts must
be possible.
(b) PARK position - Apply downward force on
the shift arm and remove pressure. Engine starts
must be possible.
(c) NEUTRAL position - Normal position. Engine
starts must be possible.
(d) NEUTRAL position - Engine running and
brakes applied, apply upward force on the shift
arm. Transmission shall not be able to shift from
neutral to reverse.
REMOVAL
(1) Shift transmission into PARK.
(2) Raise vehicle.(3) Disengage cable eyelet at transmission shift
lever and pull cable adjuster out of mounting bracket
(Fig. 102) or (Fig. 103).
Fig. 101 Front Servo
1 - PISTON RINGS
2 - SERVO PISTON
3 - O-RING
4 - SNAP-RING
5 - PISTON ROD GUIDE
6 - SEAL RING
7 - SNAP-RING
8 - SERVO SPRING
9 - WASHER
10 - SPRING
11 - PISTON ROD
Fig. 102 Gearshift Cable at Transmission - RFE
1 - GEARSHIFT CABLE
2 - RFE TRANSMISSION
3 - MANUAL LEVER
Fig. 103 Gearshift Cable at Transmission - RE
1 - GEARSHIFT CABLE
2 - RE TRANSMISSION
3 - MANUAL LEVER
21 - 210 AUTOMATIC TRANSMISSION - 48REDR
FRONT SERVO (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

INSPECTION
Inspect condition of each clutch part after cleaning.
Replace the overrunning clutch roller and spring
assembly if any rollers or springs are worn or dam-
aged, or if the roller cage is distorted, or damaged.
Replace the cam if worn, cracked or damaged.
Replace the low-reverse drum if the clutch race,
roller surface or inside diameter is scored, worn or
damaged.Do not remove the clutch race from
the low-reverse drum under any circumstances.
Replace the drum and race as an assembly if
either component is damaged.
Examine the overdrive piston retainer carefully for
wear, cracks, scoring or other damage. Be sure the
retainer hub is a snug fit in the case and drum.
Replace the retainer if worn or damaged.
ASSEMBLY
(1) Temporarily install overdrive piston retainer in
case. Use 3-4 bolts to secure retainer.
(2) Align and start new clutch cam in the trans-
mission case. Be sure serrations on cam and in case
are aligned (Fig. 181). Then tap cam into case just
enough to hold it in place.
(3) Verify that cam is correctly positioned before
proceeding any further. Narrow ends of cam ramps
should be to left when cam is viewed from front end
of case (Fig. 181).
(4) Insert Adapter Tool SP-5124 from Installer/Re-
mover C-3863-A into piston retainer (Fig. 182).
(5) Assemble Puller Bolt SP-3701 and Press Plate
SP-3583-A (Fig. 183).
Fig. 181 Positioning Replacement Clutch Cam In
Case
1 - ALIGN SERRATIONS ON CAM AND IN CASE
2 - CLUTCH CAM
Fig. 182 Positioning Adapter Tool In Overdrive
Piston Retainer
1 - PISTON RETAINER
2 - SPECIAL TOOL SP-5124
Fig. 183 Assembling Clutch Cam Puller Bolt And
Press Plate
1 - PULLER BOLT SP-3701
2 - PRESS PLATE SP-3583-A
DRAUTOMATIC TRANSMISSION - 48RE 21 - 237
OVERRUNNING CLUTCH CAM/OVERDRIVE PISTON RETAINER (Continued)