app DODGE RAM 2003 Service Repair Manual

HYDRAULIC FLOW IN DRIVE FOURTH GEAR (CONVERTER CLUTCH APPLIED)
21 - 364 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

ACCUMULATOR
DESCRIPTION
The accumulator (Fig. 68) 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. 69).
Retainer, Detent Ball and Spring - 6583
Installer, Overdrive Piston Seal - 8114
Socket, TRS Mounting Bracket - 8581
Installer, Seal - 9037
Fig. 68 Accumulator
1 - ACCUMULATOR PISTON
2 - PISTON SPRING
Fig. 69 3-4 Accumulator and Housing
1 - ACCUMULATOR PISTON
2 - 3-4 ACCUMULATOR HOUSING
3 - TEFLON SEALS
4 - PISTON SPRING
5 - COVER PLATE AND SCREWS
21 - 372 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

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. 70), bottoming it
against the accumulator plate. When the 1-2 upshift
occurs (Fig. 71), 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.
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 spring. Replace
the spring if the coils are cracked, distorted or col-
lapsed.
BANDS
DESCRIPTION
KICKDOWN (FRONT) BAND
The kickdown, or ªfrontº, band (Fig. 72) 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).
Fig. 70 Accumulator in DRIVE - FIRST Gear Position
1 - LINE PRESSURE
Fig. 71 Accumulator in SECOND Gear Position
1 - BOTTOM OF BORE
2 - LINE PRESSURE
3 - SHUTTLE VALVE
DRAUTOMATIC TRANSMISSION - 48RE 21 - 373
ACCUMULATOR (Continued)

LOW/REVERSE (REAR) BAND
The low/reverse band, or ªrearº, band (Fig. 73) is sim-
ilar 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-wrap band design (the drum is
completely encompassed/wrapped by the band). The
double-wrap band provides 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 thefront 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.
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. 74).
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 Inch Pound Torque Wrench
C-3380-A, a 3-in. extension and 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.
Fig. 72 Front Band
1 - FRONT BAND
2 - TRANSMISSION HOUSING
Fig. 73 Rear Band
1 - ADJUSTING SCREW
2 - LOCKNUT
3 - LEVER
4 - REAR BAND
5 - REACTION PIN
6 - O-RINGS
7 - PIVOT PIN
Fig. 74 Front Band Adjustment Screw Location
1 - LOCK-NUT
2 - FRONT BAND ADJUSTER
21 - 374 AUTOMATIC TRANSMISSION - 48REDR
BANDS (Continued)

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. 75).
(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.
BRAKE TRANSMISSION SHIFT
INTERLOCK SYSTEM
DESCRIPTION
The Brake Transmission Shifter Interlock (BTSI)
(Fig. 76), 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 isunlocked 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 to
LOCK. 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.
Fig. 75 Rear Band Adjustment Screw Location
1 - LOW-REVERSE BAND ADJUSTMENT
Fig. 76 Brake Transmission Interlock Mechanism
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 375
BANDS (Continued)

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. 77).
(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.
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 cylinder 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)
Fig. 77 Brake Transmission Interlock Mechanism
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
21 - 376 AUTOMATIC TRANSMISSION - 48REDR
BRAKE TRANSMISSION SHIFT INTERLOCK SYSTEM (Continued)

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. 78).
GOVERNOR PRESSURE SENSOR
The governor pressure sensor measures output
pressure of the governor pressure solenoid valve (Fig.
79).
GOVERNOR BODY AND TRANSFER PLATE
The transfer plate is designed to supply transmis-
sion line pressure to the governor pressure solenoid
valve and to return governor pressure.
The governor pressure solenoid valve is mounted in
the governor body. The body is bolted to the lower
side of the transfer plate (Fig. 79).
GOVERNOR PRESSURE CURVES
There are four governor pressure curves pro-
grammed into the transmission control module. The
different curves allow the control module to adjustgovernor pressure for varying conditions. One curve
is used for operation when fluid temperature is at, or
below, ±1ÉC (30ÉF). A second curve is used when fluid
temperature is at, or above, 10ÉC (50ÉF) during nor-
mal city or highway driving. A third curve is used
during wide-open throttle operation. The fourth curve
is used when driving with the transfer case in low
range.
OPERATION
Compensation is required for performance varia-
tions of two of the input devices. Though the slope of
the transfer functions is tightly controlled, offset may
vary due to various environmental factors or manu-
facturing tolerances.
The pressure transducer is affected by barometric
pressure as well as temperature. Calibration of the
zero pressure offset is required to compensate for
shifting output due to these factors.
Normal calibration will be performed when sump
temperature is above 50 degrees F, or in the absence
of sump temperature data, after the first 10 minutes
of vehicle operation. Calibration of the pressure
transducer offset occurs each time the output shaft
speed falls below 200 RPM. Calibration shall be
repeated each 3 seconds the output shaft speed is
below 200 RPM. A 0.5 second pulse of 95% duty cycle
is applied to the governor pressure solenoid valve
and the transducer output is read during this pulse.
Averaging of the transducer signal is necessary to
reject electrical noise.
Under cold conditions (below 50 degrees F sump),
the governor pressure solenoid valve response may
be too slow to guarantee 0 psi during the 0.5 second
calibration pulse. Calibration pulses are continued
during this period, however the transducer output
valves are discarded. Transducer offset must be read
at key-on, under conditions which promote a stable
reading. This value is retained and becomes the off-
set during the9cold9period of operation.
GOVERNOR PRESSURE SOLENOID VALVE
The inlet side of the solenoid valve is exposed to
normal transmission line pressure. The outlet side of
the valve leads to the valve body governor circuit.
The solenoid valve regulates line pressure to produce
governor pressure. The average current supplied to the
solenoid controls governor pressure. One amp current
produces zero kPa/psi governor pressure. Zero amps sets
the maximum governor pressure.
The powertrain control module (PCM) turns on the
trans control relay which supplies electrical power to
the solenoid valve. Operating voltage is 12 volts
(DC). The PCM controls the ground side of the sole-
noid using the governor pressure solenoid control cir-
cuit.
Fig. 78 Governor Pressure Solenoid Valve
1 - SOLENOID FILTER
2 - GOVERNOR PRESSURE SOLENOID
Fig. 79 Governor Pressure Sensor
1 - GOVERNOR BODY
2 - GOVERNOR PRESSURE SENSOR/TRANSMISSION FLUID
TEMPERATURE THERMISTOR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 377
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)

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. 91).
(4)
Loosen bolts holding rear of pan to transmission.
(5) Slowly separate front of pan and gasket away
from transmission allowing the fluid to drain into
drain pan.
(6) Hold up pan and remove remaining bolt hold-
ing pan to transmission.
(7) While holding pan level, lower pan and gasket
away from transmission.
(8) Pour remaining fluid in pan into drain pan.
(9) Remove screws holding filter to valve body
(Fig. 92).
(10) Separate filter from valve body and pour fluid
in filter into drain pan.
(11) Dispose of used trans fluid and filter properly.
INSTALLATION
(1) Position a new transmission oil filter onto the
valve body.
(2) Install the screws to hold the filter to the valve
body. Tighten the screws to 4 N´m (35 in.lbs.).
(3) Clean the gasket surfaces of the transmission
oil pan and transmission pan rail.NOTE: The transmission pan oil gasket is reusable.
Inspect the sealing surfaces of the gasket. If the
sealing ribs on both surfaces appear to be in good
condition, clean the gasket of any foreign material
and reinstall.
(4) Position the oil pan gasket onto the oil pan.
(5) Position the oil pan and gasket onto the trans-
mission and install several bolts to hold the pan and
gasket to the transmission.
(6) Install the remainder of the oil pan bolts.
Tighten the bolts to 13.6 N´m (125 in.lbs.).
(7) Lower vehicle and fill transmission. (Refer to
21 - TRANSMISSION/AUTOMATIC/FLUID - STAN-
DARD PROCEDURE)
STANDARD PROCEDURE - TRANSMISSION
FILL
To avoid overfilling transmission after a fluid
change or overhaul, perform the following procedure:
(1) Remove dipstick and insert clean funnel in
transmission fill tube.
(2) Add following initial quantity of MopartAT F
+4, Automatic Transmission Fluid, to transmission:
(a) If only fluid and filter were changed, add3
pints (1-1/2 quarts)of ATF +4 to transmission.
(b) If transmission was completely overhauled,
or torque converter was replaced or drained, add
12 pints (6 quarts)of ATF +4 to transmission.
(3) Apply parking brakes.
(4)
Start and run engine at normal curb idle speed.
(5)Apply service brakes, shift transmission through
all gear ranges then back to NEUTRAL, set parking
brake, and leave engine running at curb idle speed.
(6) Remove funnel, insert dipstick and check fluid
level. If level is low,add fluid to bring level to
MIN mark on dipstick.Check to see if the oil level
Fig. 91 Transmission Pan
1 - TRANSMISSION
2 - GASKET
3-PAN
Fig. 92 Transmission Filter
1 - TRANSMISSION
2 - FILTER
DRAUTOMATIC TRANSMISSION - 48RE 21 - 383
FLUID AND FILTER (Continued)

is equal on both sides of the dipstick. If one side is
noticably higher than the other, the dipstick has
picked up some oil from the dipstick tube. Allow the
oil to drain down the dipstick tube and re-check.
(7) Drive vehicle until transmission fluid is at nor-
mal operating temperature.
(8) With the engine running at curb idle speed, the
gear selector in NEUTRAL, and the parking brake
applied, check the transmission fluid level.
CAUTION: Do not overfill transmission, fluid foam-
ing and shifting problems can result.
(9)
Add fluid to bring level up to MAX arrow mark.
When fluid level is correct, shut engine off, release
park brake, remove funnel, and install dipstick in fill
tube.
FRONT CLUTCH
DESCRIPTION
The front clutch assembly (Fig. 93) is composed of
the front clutch retainer, pressure plate, clutch
plates, driving discs, piston, piston return spring,
return spring retainer, and snap-rings. The front
clutch is the forward-most component in the trans-
mission geartrain and is directly behind the oil pump
and is considered a driving component.
OPERATION
To apply the clutch, pressure is applied between the
clutch retainer and piston. The fluid pressure is pro-
vided by the oil pump, transferred through the control
valves and passageways, and enters the clutch through
the hub of the reaction shaft support. With pressure
applied between the clutch retainer and piston, the pis-
ton moves away from the clutch retainer and com-
presses the clutch pack. This action applies the clutch
pack, allowing torque to flow through the input shaft
into the driving discs, and into the clutch plates and
pressure plate that are lugged to the clutch retainer.
The waved snap-ring is used to cushion the application
of the clutch pack.
When pressure is released from the piston, the spring
returns the piston to its fully released position and dis-
engages the clutch. The release spring also helps to
cushion the application of the clutch assembly. When
the clutch is in the process of being released by the
release spring, fluid flows through a vent and one-way
ball-check-valve located in the clutch retainer. The
check-valve is needed to eliminate the possibility of
plate drag caused by centrifugal force acting on the
residual fluid trapped in the clutch piston retainer.
DISASSEMBLY
(1) Remove the waved snap-ring, reaction plate,
clutch plates, and clutch discs.
Fig. 93 48RE Front Clutch Components
1 - INNER PISTON SEAL 7 - CLUTCH DISCS
2 - CLUTCH PISTON 8 - RETAINER SNAP-RING
3 - CLUTCH PISTON SPRING RETAINER 9 - CLUTCH PISTON SPRINGS
4 - CLUTCH PLATES 10 - OUTER PISTON SEAL
5 - CLUTCH PACK SNAP-RING (WAVED) 11 - FRONT CLUTCH RETAINER
6 - REACTION PLATE
21 - 384 AUTOMATIC TRANSMISSION - 48REDR
FLUID AND FILTER (Continued)