DODGE RAM 2003 Service Repair Manual

OIL PUMP
DESCRIPTION
The oil pump (Fig. 111) is located in the pump
housing inside the bell housing of the transmission
case. The oil pump consists of an inner and outer
gear, a housing, and a reaction shaft support.
OPERATION
As the torque converter rotates, the converter hub
rotates the inner and outer gears. As the gears
rotate, the clearance between the gear teeth
increases in the crescent area, and creates a suction
at the inlet side of the pump. This suction draws
fluid through the pump inlet from the oil pan. As the
clearance between the gear teeth in the crescent area
decreases, it forces pressurized fluid into the pump
outlet and to the valve body.
Fig. 111 Oil Pump Assembly
1 - OIL SEAL 7 - BOLTS (6)
2 - VENT BAFFLE 8 - #1 THRUST WASHER (SELECTIVE)
3 - OIL PUMP BODY 9 - INNER GEAR
4 - GASKET 10 - OUTER GEAR
5 - REACTION SHAFT SUPPORT 11 - ªOº RING
6 - SEAL RINGS 12 - TORQUE CONVERTER SEAL RING
21 - 392 AUTOMATIC TRANSMISSION - 48REDR

DISASSEMBLY
(1) Mark position of support in oil pump body for
assembly alignment reference. Use scriber or paint to
make alignment marks.
(2) Place pump body on two wood blocks.
(3) Remove reaction shaft support bolts and sepa-
rate support from pump body (Fig. 112).
(4) Remove pump inner and outer gears (Fig. 113).
(5) Remove o-ring seal from pump body (Fig. 114).
Discard seal after removal.
(6) Remove oil pump seal with Remover Tool
C-3981. Discard seal after removal.
CLEANING
Clean pump and support components with solvent
and dry them with compressed air.
INSPECTION
Check condition of the seal rings and thrust
washer on the reaction shaft support. The seal rings
do not need to be replaced unless cracked, broken, or
severely worn.
Inspect the pump and support components. Replace
the pump or support if the seal ring grooves or
machined surfaces are worn, scored, pitted, or dam-
aged. Replace the pump gears if pitted, worn
chipped, or damaged.
Inspect the pump bushing. Then check the reaction
shaft support bushing. Replace either bushing only if
heavily worn, scored or damaged. It is not necessary
to replace the bushings unless they are actually dam-
aged.
Clearance between outer gear and reaction shaft
housing should be 0.010 to 0.063 mm (0.0004 to
0.0025 in.). Clearance between inner gear and reac-
tion shaft housing should be 0.010 to 0.063 mm
(0.0004 to 0.0025 in.). Both clearances can be mea-sured at the same time by installing the gears in the
pump body and measure pump component clearances
as follows:
(1) Position an appropriate piece of PlastigageŸ
across both gears.
(2) Align the plastigage to a flat area on the reac-
tion shaft housing.
(3) Install the reaction shaft to the pump housing.
(4) Separate the reaction shaft housing from the
pump housing and measure the PlastigageŸ follow-
ing the instructions supplied with it.
Clearance between inner gear tooth and outer gear
should be 0.051 to 0.19 mm (0.002 to 0.0075 in.).
Measure clearance with an appropriate feeler gauge
(Fig. 115).
Clearance between outer gear and pump housing
should be 0.10 to 0.229 mm (0.004 to 0.009 in.). Mea-
sure clearance with an appropriate feeler gauge.
ASSEMBLY
(1) Lubricate pump gears with transmission fluid
and install them in pump body.
(2) Install thrust washer on reaction shaft support
hub. Lubricate washer with petroleum jelly or trans-
mission fluid before installation.
(3) If reaction shaft seal rings are being replaced,
install new seal rings on support hub. Lubricate seal
rings with transmission fluid or petroleum jelly after
installation. Squeeze each ring until ring ends are
securely hooked together.
Fig. 112 Reaction Shaft Support
1 - OIL PUMP
2 - REACTION SHAFT SUPPORT
Fig. 113 Pump Gears
1 - GEAR BORE
2 - PUMP BODY
3 - INNER GEAR
4 - OUTER GEAR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 393
OIL PUMP (Continued)

CAUTION: The reaction shaft support seal rings will
break if overspread, or twisted. If new rings are
being installed, spread them only enough for instal-
lation. Also be very sure the ring ends are securely
hooked together after installation. Otherwise, the
rings will either prevent pump installation, or break
during installation.
(4) Align and install reaction shaft support on
pump body.
(5) Install bolts attaching reaction shaft support to
pump. Tighten bolts to 20 N´m (175 in. lbs.) torque.
Fig. 114 Oil Pump Assembly
1 - OIL SEAL 7 - BOLTS (6)
2 - VENT BAFFLE 8 - #1 THRUST WASHER (SELECTIVE)
3 - OIL PUMP BODY 9 - INNER GEAR
4 - GASKET 10 - OUTER GEAR
5 - REACTION SHAFT SUPPORT 11 - ªOº RING
6 - SEAL RINGS 12 - TORQUE CONVERTER SEAL RING
Fig. 115 Checking Pump Gear Tip Clearance
1 - FEELER GAUGE
2 - INNER GEAR
3 - OUTER GEAR
21 - 394 AUTOMATIC TRANSMISSION - 48REDR
OIL PUMP (Continued)

(6) Install new pump seal with Installer Tool
C-3860-A (Fig. 116). Use hammer or mallet to tap
seal into place.
(7) Install new o-ring on pump body. Lubricate oil
seal and o-ring with petroleum jelly.
(8) Cover pump assembly to prevent dust entry
and set aside for assembly installation.
OUTPUT SHAFT FRONT
BEARING
REMOVAL
(1) Remove overdrive unit from the vehicle.
(2) Remove overdrive geartrain from housing.
(3) Remove snap-ring holding output shaft front
bearing to overdrive geartrain. (Fig. 117).
(4) Pull bearing from output shaft.
INSTALLATION
(1) Place replacement bearing in position on
geartrain with locating retainer groove toward the
rear.
(2) Push bearing onto shaft until the snap-ring
groove is visible.
(3) Install snap-ring to hold bearing onto output
shaft.
(4) Install overdrive geartrain into housing.
(5) Install overdrive unit in vehicle.
OUTPUT SHAFT REAR
BEARING
REMOVAL
(1) Remove overdrive unit from the vehicle. (Refer
to 21 - TRANSMISSION/AUTOMATIC/OVERDRIVE
- REMOVAL)
(2) Remove overdrive geartrain from housing.
(3) Remove snap-ring holding output shaft rear
bearing into overdrive housing (Fig. 118).
(4) Using a suitable driver inserted through the
rear end of housing, drive bearing from housing.
Fig. 116 Oil Pump Seal
1 - SPECIAL TOOL C-3860-A
2 - PUMP BODY
3 - PUMP SEAL
Fig. 117 Output Shaft Front Bearing
1 - OUTPUT SHAFT FRONT BEARING
2 - SNAP-RING
3 - OUTPUT SHAFT
4 - GROOVE TO REAR
5 - OVERDRIVE GEARTRAIN
Fig. 118 Output Shaft Rear Bearing
1 - OUTPUT SHAFT REAR BEARING
2 - OVERDRIVE HOUSING
3 - SNAP-RING
DRAUTOMATIC TRANSMISSION - 48RE 21 - 395
OIL PUMP (Continued)

INSTALLATION
(1) Place replacement bearing in position in hous-
ing.
(2) Using a suitable driver, drive bearing into
housing until the snap-ring groove is visible.
(3) Install snap-ring to hold bearing into housing
(Fig. 118).
(4) Install overdrive geartrain into housing.
(5) Install overdrive unit in vehicle.
OVERDRIVE CLUTCH
DESCRIPTION
The overdrive clutch (Fig. 119) is composed of the
pressure plate, clutch plates, holding discs, overdrive
piston retainer, piston, piston spacer, and snap-rings.
The overdrive clutch is the forwardmost component
in the transmission overdrive unit and is considered
a holding component. The overdrive piston retainer,
piston, and piston spacer are located on the rear of
the main transmission case.
NOTE: The number of discs and plates may vary
with each engine and vehicle combination.
OPERATION
To apply the clutch, pressure is applied between
the piston retainer and piston. The fluid pressure is
provided by the oil pump, transferred through the
control valves and passageways, and enters the
clutch through passages at the lower rear portion of
the valve body area. With pressure applied between
the piston retainer and piston, the piston moves
away from the piston retainer and compresses the
clutch pack. This action applies the clutch pack,
allowing torque to flow through the intermediate
shaft into the overdrive planetary gear set. The over-
drive clutch discs are attached to the overdrive clutch
hub while the overdrive clutch plates, reaction plate,
and pressure plate are lugged to the overdrive hous-
ing. This allows the intermediate shaft to transfer
the engine torque to the planetary gear and overrun-
ning clutch. This drives the planetary gear inside the
annulus, which is attached to the overdrive clutch
drum and output shaft, creating the desired gear
ratio. The waved snap-ring is used to cushion the
application of the clutch pack for the 5 disc version of
the overdrive clutch. The 6 disc overdrive clutch does
not use a waved snap-ring.
Fig. 119 Overdrive Clutch
1 - REACTION PLATE 2 - PRESSURE PLATE
21 - 396 AUTOMATIC TRANSMISSION - 48REDR
OUTPUT SHAFT REAR BEARING (Continued)

OVERDRIVE SWITCH
DESCRIPTION
The overdrive OFF (control) switch is located in
the shift lever arm (Fig. 120). The switch is a
momentary contact device that signals the PCM to
toggle current status of the overdrive function.
OPERATION
At key-on, overdrive operation is allowed. Pressing
the switch once causes the overdrive OFF mode to be
entered and the overdrive OFF switch lamp to be
illuminated. Pressing the switch a second time
causes normal overdrive operation to be restored and
the overdrive lamp to be turned off. The overdrive
OFF mode defaults to ON after the ignition switch is
cycled OFF and ON. The normal position for the con-
trol 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 overdrive switch is turned to the OFF
position, or when illuminated by the transmission
control module.
DIAGNOSIS AND TESTING - OVERDRIVE
ELECTRICAL CONTROLS
The overdrive off switch, valve body solenoid, case
connectors and related wiring can all be tested with
a 12 volt test lamp or a volt/ohmmeter. Check conti-
nuity 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 overdrive
off switch retainer from the shift lever (Fig. 121).(2) Pull the switch outwards to release it from the
connector in the lever (Fig. 122)
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
overdrive off switch. Use care when installing the
switch, as it is not indexed, and can be accidentally
installed incorrectly.
Fig. 120 Overdrive Off Switch
Fig. 121 Overdrive Off Switch Retainer
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH RETAINER
3 - PLASTIC TRIM TOOL
Fig. 122 Remove the Overdrive Off Switch
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH
DRAUTOMATIC TRANSMISSION - 48RE 21 - 397

(2) Install the overdrive off switch into the connec-
tor (Fig. 123)
(3) Push the overdrive off switch and wiring into
the shift lever.
(4) Install the overdrive off switch retainer onto
the shift lever.
OVERDRIVE UNIT
REMOVAL
(1) Shift transmission into PARK.
(2) Raise vehicle.
(3) Remove transfer case, if equipped.
(4) Mark propeller shaft universal joint(s) and axle
pinion yoke, or the companion flange and flange
yoke, for alignment reference at installation, if neces-
sary.
(5) Disconnect and remove the rear propeller shaft,
if necessary. (Refer to 3 - DIFFERENTIAL & DRIV-
ELINE/PROPELLER SHAFT/PROPELLER SHAFT -
REMOVAL)
(6) Remove transmission oil pan, remove gasket,
drain oil and reinstall pan.
(7) If overdrive unit had malfunctioned, or if fluid
is contaminated, remove entire transmission. If diag-
nosis indicated overdrive problems only, remove just
the overdrive unit.
(8) Support transmission with transmission jack.
(9) Remove bolts attaching overdrive unit to trans-
mission (Fig. 124).CAUTION: Support the overdrive unit with a jack
before moving it rearward. This is necessary to pre-
vent damaging the intermediate shaft. Do not allow
the shaft to support the entire weight of the over-
drive unit.
(10) Carefully work overdrive unit off intermediate
shaft. Do not tilt unit during removal. Keep it as
level as possible.
(11) If overdrive unit does not require service,
immediately insert Alignment Tool 6227-2 in splines
of planetary gear and overrunning clutch to prevent
splines from rotating out of alignment. If misalign-
ment occurs, overdrive unit will have to be disassem-
bled in order to realign splines.
(12) Remove and retain overdrive piston thrust
bearing. Bearing may remain on piston or in clutch
hub during removal.
(13) Position drain pan on workbench.
(14) Place overdrive unit over drain pan. Tilt unit
to drain residual fluid from case.
(15) Examine fluid for clutch material or metal
fragments. If fluid contains these items, overhaul will
be necessary.
(16) If overdrive unit does not require any service,
leave alignment tool in position. Tool will prevent
accidental misalignment of planetary gear and over-
running clutch splines.
Fig. 123 Install the Overdrive Off Switch
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH WIRING CONNECTOR
3 - OVERDRIVE OFF SWITCH
Fig. 124 Overdrive Unit Bolts
1 - OVERDRIVE UNIT
2 - ATTACHING BOLTS (7)
21 - 398 AUTOMATIC TRANSMISSION - 48REDR
OVERDRIVE SWITCH (Continued)

DISASSEMBLY
(1) Remove transmission speed sensor and o-ring
seal from overdrive case (Fig. 125).
(2) Remove overdrive piston thrust bearing (Fig.
126).
OVERDRIVE PISTON
(1) Remove overdrive piston thrust plate (Fig.
127). Retain thrust plate. It is a select fit part and
may possibly be reused.
(2) Remove intermediate shaft spacer (Fig. 128).
Retain spacer. It is a select fit part and may possibly
be reused.
Fig. 125 Transmission Speed Sensor
1 - SOCKET AND WRENCH
2 - SPEED SENSOR
3 - O-RING
Fig. 126 Overdrive Piston Thrust Bearing Removal/
Installation
1 - THRUST BEARING
2 - OVERDRIVE PISTON
3 - THRUST PLATE
Fig. 127 Overdrive Piston Thrust Plate Removal/
Installation
1 - OVERDRIVE PISTON
2 - OVERDRIVE PISTON SPACER (SELECT FIT)
Fig. 128 Intermediate Shaft Spacer Location
1 - INTERMEDIATE SHAFT
2 - INTERMEDIATE SHAFT SPACER (SELECT FIT)
DRAUTOMATIC TRANSMISSION - 48RE 21 - 399
OVERDRIVE UNIT (Continued)

(3) Remove overdrive piston from retainer (Fig.
129).
OVERDRIVE CLUTCH PACK
(1) Remove overdrive clutch pack wire retaining
ring (Fig. 130).
(2) Remove overdrive clutch pack (Fig. 131).
(3) Note position of clutch pack components for
assembly reference (Fig. 132).
OVERDRIVE GEARTRAIN
(1) Remove overdrive clutch wave spring (Fig.
133), 5 disc clutch only.
Fig. 129 Overdrive Piston Removal
1 - PISTON RETAINER
2 - OVERDRIVE PISTON
Fig. 130 Removing Overdrive Clutch Pack Retaining
Ring
1 - OVERDRIVE CLUTCH PACK RETAINING RING
Fig. 131 Overdrive Clutch Pack Removal
1 - OVERDRIVE CLUTCH PACK
Fig. 132 Overdrive Clutch Component Position -
Typical
1 - REACTION PLATE 3 - PRESSURE PLATE
2 - CLUTCH PLATES 4 - CLUTCH DISCS
Fig. 133 Overdrive Clutch Wave Spring Removal - 5
Disc Clutch Only
1 - WAVE SPRING
21 - 400 AUTOMATIC TRANSMISSION - 48REDR
OVERDRIVE UNIT (Continued)

(2) Remove overdrive clutch reaction snap-ring
(Fig. 134). Note that snap-ring is located in same
groove as wave spring.
(3) Remove TorxŸ head screws that attach access
cover and gasket to overdrive case (Fig. 135).
(4) Remove access cover and gasket (Fig. 136).(5) Expand output shaft bearing snap-ring with
expanding-type snap-ring pliers. Then push output
shaft forward to release shaft bearing from locating
ring (Fig. 137).
(6) Lift gear case up and off geartrain assembly
(Fig. 138).
Fig. 134 Overdrive Clutch Reaction Snap-Ring
Removal
1 - REACTION RING
2 - CLUTCH HUB
Fig. 135 Access Cover Screw Removal
1 - TORX SCREWDRIVER (T25)
2 - ACCESS COVER SCREWS
Fig. 136 Access Cover And Gasket Removal
1 - ACCESS COVER AND GASKET
Fig. 137 Releasing Bearing From Locating Ring
1 - EXPAND BEARING LOCATING RING WITH SNAP-RING
PLIERS
2 - ACCESS HOLE
Fig. 138 Removing Geartrain
1 - GEARTRAIN ASSEMBLY
2 - GEAR CASE
DRAUTOMATIC TRANSMISSION - 48RE 21 - 401
OVERDRIVE UNIT (Continued)