2003 DODGE RAM Fuel

TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 249) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The torque
converter hub drives the transmission oil (fluid)
pump.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid.
Fig. 249 Torque Converter Assembly
1 - TURBINE
2 - IMPELLER
3 - HUB
4-STATOR
5 - FRONT COVER
6 - CONVERTER CLUTCH DISC
7 - DRIVE PLATE
DRAUTOMATIC TRANSMISSION - 46RE 21 - 257

IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan gas-
ket surface (Fig. 2). Refer to this information when
ordering replacement parts.
GEAR RATIOS
The 48RE gear ratios are:
1st.................................2.45:1
2nd................................1.45:1
3rd................................1.00:1
4th.................................0.69:1
Rev.................................2.20:1
OPERATION
The application of each driving or holding compo-
nent is controlled by the valve body based upon the
manual lever position, throttle pressure, and gover-
nor pressure. The governor pressure is a variable
pressure input to the valve body and is one of the
signals that a shift is necessary. First through fourth
gear are obtained by selectively applying and releas-
ing the different clutches and bands. Engine power is
thereby routed to the various planetary gear assem-
blies which combine with the overrunning clutch
assemblies to generate the different gear ratios. The
torque converter clutch is hydraulically applied and
is released when fluid is vented from the hydraulic
circuit by the torque converter control (TCC) solenoid
on the valve body. The torque converter clutch is con-
trolled by the Powertrain Control Module (PCM). The
torque converter clutch engages in fourth gear, and
in third gear under various conditions, such as when
the O/D switch is OFF, when the vehicle is cruising
on a level surface after the vehicle has warmed up.
The torque converter clutch can also be engaged in
the manual second gear position if high transmission
temperatures are sensed by the PCM. The torque
converter clutch will disengage momentarily when an
increase in engine load is sensed by the PCM, such
as when the vehicle begins to go uphill or the throttle
pressure is increased. The torque converter clutch
feature increases fuel economy and reduces the
transmission fluid temperature.
Since the overdrive clutch is applied in fourth gear
only and the direct clutch is applied in all ranges
except fourth gear, the transmission operation for
park, neutral, and first through third gear will be
described first. Once these powerflows are described,
the third to fourth shift sequence will be described.
1 - TORQUE CONVERTER 10 - OVERDRIVE CLUTCH
2 - INPUT SHAFT 11 - DIRECT CLUTCH
3 - OIL PUMP 12 - PLANETARY GEAR
4 - FRONT BAND 13 - INTERMEDIATE SHAFT
5 - FRONT CLUTCH 14 - OVERDRIVE OVERRUNNING CLUTCH
6 - REAR CLUTCH 15 - DIRECT CLUTCH SPRING
7 - PLANETARIES 16 - OVERDRIVE PISTON RETAINER
8 - REAR BAND 17 - OIL PAN
9 - OVERRUNNING CLUTCH 18 - VALVE BODY
Fig. 2 Transmission Part And Serial Number
Location
1 - PART NUMBER
2 - BUILD DATE
3 - SERIAL NUMBER
21 - 314 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR
Damaged or worn threads in the aluminum trans-
mission case and valve body can be repaired by the
use of Heli-CoilsŸ, or equivalent. This repair con-
sists of drilling out the worn-out damaged threads.
Then tap the hole with a special Heli-CoilŸ tap, or
equivalent, and installing a Heli-CoilŸ insert, or
equivalent, into the hole. This brings the hole back to
its original thread size.
Heli-CoilŸ, or equivalent, tools and inserts are
readily available from most automotive parts suppli-
ers.
REMOVAL
NOTE: The overdrive unit can be removed and ser-
viced separately. It is not necessary to remove the
entire transmission assembly to perform overdrive
unit repairs.
(1) Disconnect battery negative cable.
(2) Raise vehicle.
(3) Remove the transfer case skid plate (Fig. 12), if
equipped.(4) Disconnect and lower or remove necessary
exhaust components.
(5) Remove engine-to-transmission struts (Fig. 13)
and (Fig. 14).
(6) Remove starter motor. (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - REMOVAL)
(7) Disconnect and remove the crankshaft position
sensor. (Refer to 14 - FUEL SYSTEM/FUEL INJEC-
TION/CRANKSHAFT POSITION SENSOR -
REMOVAL) Retain the sensor attaching bolts.
(8) If transmission is being removed for overhaul,
remove transmission oil pan, drain fluid and reinstall
pan.
(9) Remove torque converter access cover.
Fig. 12 Transfer Case Skid Plate
1 - FRAME RAIL
2 - SKID PLATE
3 - BOLTS (6)
Fig. 13 Right Side Engine-to-Transmission Strut
1 - TRANSMISSION
2 - ENGINE
3 - STRUT
Fig. 14 Left Side Engine-to-Transmission Strut
1 - TRANSMISSION
2 - ENGINE
3 - STRUT
DRAUTOMATIC TRANSMISSION - 48RE 21 - 337
AUTOMATIC TRANSMISSION - 48RE (Continued)

(12) Carefully work transmission forward and over
engine block dowels until converter hub is seated in
crankshaft.
(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. 66) 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. 67) 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. 65 Checking Converter Seating - Typical
1 - SCALE
2 - STRAIGHTEDGE
Fig. 66 Gearshift Cable At Transmission
1 - GEARSHIFT CABLE
2 - TRANSMISSION MANUAL LEVER
3 - CABLE SUPPORT BRACKET
Fig. 67 Transmission Cooler Lines
1 - TRANSMISSION
2 - RADIATOR
3 - COOLER LINES
21 - 354 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

in an incorrect T.V. cable adjustment.Slide the
sheath of the T.V. cable (D) back and forth until the
centerlines of the T.V. cable end (B) and the throttle
bell crank lever (C) are aligned within one millimeter
(1mm) (Fig. 232).
(7) While holding the T.V. cable in the set position
push the T.V. cable lock (A) into the down position
(Fig. 232). This will lock the present T.V. cable
adjustment.
NOTE: Be sure that as the cable is pulled forward
and centered on the throttle lever stud, the cable
housing moves smoothly with the cable. Due to the
angle at which the cable housing enters the spring
housing, the cable housing may bind slightly and
create an incorrect adjustment.
(8) Reconnect the T.V. cable (B) to the throttle
bellcrank lever (C).
(9) Check cable adjustment. Verify transmission
throttle lever and lever on throttle body move simul-
taneously.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 233) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The torque
converter hub drives the transmission oil (fluid)
pump.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid. If the fluid
is contaminated, flush the all transmission fluid
cooler(s) and lines.
Fig. 233 Torque Converter Assembly
1 - TURBINE
2 - IMPELLER
3 - HUB
4-STATOR
5 - FRONT COVER
6 - CONVERTER CLUTCH DISC
7 - DRIVE PLATE
21 - 434 AUTOMATIC TRANSMISSION - 48REDR
THROTTLE VALVE CABLE (Continued)

The strength of the magnetic field is the primary
force that determines the speed of operation in a par-
ticular solenoid design. A stronger magnetic field will
cause the plunger to move at a greater speed than a
weaker one. There are basically two ways to increase
the force of the magnetic field:
1. Increase the amount of current applied to the
coil or
2. Increase the number of turns of wire in the coil.
The most common practice is to increase the num-
ber of turns by using thin wire that can completely
fill the available space within the solenoid housing.
The strength of the spring and the length of the
plunger also contribute to the response speed possi-
ble by a particular solenoid design.
A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 117) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, an
overrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The torque
converter hub drives the transmission oil (fluid)
pump and contains an o-ring seal to better control oil
flow.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid.
Fig. 117 Torque Converter Assembly
1 - TURBINE ASSEMBLY
2-STATOR
3 - CONVERTER HUB
4 - O-RING
5 - IMPELLER ASSEMBLY
6 - CONVERTER CLUTCH PISTON
7 - TURBINE HUB
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 575
SOLENOIDS (Continued)

TIRE CHAINS
Tire snow chains may be used oncertainmodels.
Refer to the Owner's Manual for more information.
DESCRIPTION - RADIAL ± PLY TIRES
Radial-ply tires improve handling, tread life and
ride quality, and decrease rolling resistance.
Radial-ply tires must always be used in sets of
four. Under no circumstances should they be used on
the front only. They may be mixed with temporary
spare tires when necessary. A maximum speed of 50
MPH is recommended while a temporary spare is in
use.
Radial-ply tires have the same load-carrying capac-
ity as other types of tires of the same size. They also
use the same recommended inflation pressures.
The use of oversized tires, either in the front or
rear of the vehicle, can cause vehicle drive train fail-
ure. This could also cause inaccurate wheel speed
signals when the vehicle is equipped with Anti-Lock
Brakes.
The use of tires from different manufactures on the
same vehicle is NOT recommended. The proper tire
pressure should be maintained on all four tires.
DESCRIPTION - TIRE PRESSURE FOR HIGH
SPEEDS
Where speed limits allow the vehicle to be driven at
high speeds, correct tire inflation pressure is very
important. For speeds up to and including 120 km/h (75
mph), tires must be inflated to the pressures shown on
the tire placard. For continuous speeds in excess of 120
km/h (75 mph), tires must be inflated to the maximum
pressure specified on the tire sidewall.
Vehicles loaded to the maximum capacity should not
be driven at continuous speeds above 75 mph (120
km/h).
For emergency vehicles that are driven at speeds
over 90 mph (144 km/h), special high speed tires
must be used. Consult tire manufacturer for correct
inflation pressure recommendations.
DESCRIPTION - REPLACEMENT TIRES
The original equipment tires provide a proper bal-
ance of many characteristics such as:
²Ride
²Noise
²Handling
²Durability
²Tread life
²Traction
²Rolling resistance
²Speed capability
It is recommended that tires equivalent to the orig-
inal equipment tires be used when replacement is
needed.
Failure to use equivalent replacement tires may
adversely affect the safety and handling of the vehicle.
The use of oversize tires may cause interference
with vehicle components. Under extremes of suspen-
sion and steering travel, interference with vehicle
components may cause tire damage.
WARNING: FAILURE TO EQUIP THE VEHICLE WITH
TIRES HAVING ADEQUATE SPEED CAPABILITY
CAN RESULT IN SUDDEN TIRE FAILURE.
DESCRIPTION - TIRE INFLATION PRESSURES
Under inflation will cause rapid shoulder wear, tire
flexing, and possible tire failure (Fig. 12).
Over inflation will cause rapid center wear and
loss of the tire's ability to cushion shocks (Fig. 13).
Improper inflation can cause:
²Uneven wear patterns
²Reduced tread life
²Reduced fuel economy
²Unsatisfactory ride
²Vehicle drift
For proper tire pressure specification refer to the Tire
Inflation Pressure Chart provided with the vehicles
Fig. 11 Tire Identification
22 - 6 TIRES/WHEELSDR
TIRES (Continued)

SPECIFICATIONS - TORQUE
TORQUE SPECIFICATIONS
Description N´m Ft. Lbs. In. Lbs.
A-pillar trim/grab handle bolts 6 Ð 55
Body Isolator/cab bolts 81 60 Ð
Cargo box bolts 108 80 Ð
Cargo box tie down/cleat bolts 34 25 Ð
Center seat assembly nuts*25 18 Ð
Center seat cushion/hinge bolts*20 15 Ð
Center seat back hinge to storage bin bolts*25 18 Ð
Center seat back free pivot hinge bolt*25 18 Ð
Center seat back inertia hinge pivot bolt*10 Ð 89
Center seat inertia hinge to seat back bolts*25 18 Ð
Fender bolts - front lower 9 Ð 80
Fender bolts - lower inside 17 13 Ð
Fender to hinge support bolts 11 8 Ð
Fender to upper fender rail bolts 9 Ð 80
Footmans loop bolts 12 9 Ð
Front center seat nuts*25 18 Ð
Front door glass lift plate nuts 10 Ð 89
Front door hinge to a-pillar nuts 28 21 Ð
Front door hinge to door nuts/bolts 28 21 Ð
Front door inside handle bolt 9 Ð 80
Front door latch adjustment screw 3 Ð 30
Front door latch assembly bolts 10 Ð 89
Front door latch striker bolts 28 21 Ð
Front door latch striker bolts 28 21 Ð
Front door regulator bolts 10 Ð 89
Front door regulator stabilizer nuts 10 Ð 89
Front door remote handle actuator nuts 10 Ð 89
Front door run channel screws 10 Ð 89
Front seat assembly front bolts*28 30 Ð
Front seat assembly rear bolts*40 30 Ð
Front seat track nuts*25 18 Ð
Fuel fill door bolts 9 Ð 80
Hood hinge to fender rail bolts 20 15 Ð
Hood latch bolts 11 8 Ð
Hood latch striker/safety catch bolts 11 8 Ð
Hood hinge to hood nuts 23 17 Ð
Instrument panel center bracket bolts 12 9 Ð
Instrument panel column support bolts 14 10 Ð
Instrument panel side mounting bolts 12 9 Ð
23 - 12 BODYDR
BODY (Continued)