1998 DODGE RAM 1500 one

FLUID AND FILTER
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxi-
dation and varnish buildup which interferes with
valve and clutch operation. Foaming also causes fluid
expansion which can result in fluid overflow from the
transmission vent or fill tube. Fluid overflow can eas-
ily be mistaken for a leak if inspection is not careful.
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has three primary causes.
(1) Internal clutch slippage, usually caused by low
line pressure, inadequate clutch apply pressure, or
clutch seal failure.
(2) A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged main cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.
(3) Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to replace contaminated converter after
repairThe use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failure
due to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The torque converter should also be replaced when-
ever a failure generates sludge and debris. This is
necessary because normal converter flushing proce-
dures will not remove all contaminants.
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can
interfere with normal valve, clutch, and accumulator
operation. Foaming can also result in fluid escaping
from the transmission vent where it may be mis-
taken for a leak.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
The transmission has a dipstick to check oil level.
It is located on the right side of the engine. Be sure
to wipe all dirt from dipstick handle before removing.
The torque converter fills in both the P (PARK)
and N (NEUTRAL) positions. Place the selector lever
in P (PARK) to be sure that the fluid level check is
accurate.The engine should be running at idle
speed for at least one minute, with the vehicle
on level ground.At normal operating temperature
(approximately 82 C. or 180 F.), the fluid level is cor-
rect if it is in the HOT region (cross-hatched area) on
the oil level indicator. The fluid level will be approx-
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INSTALLATION
(1) Route the transmission end of the gearshift
cable through the opening in the dash panel (Fig.
72).
(2) Seat the cable grommet into the dash panel
opening.
(3) Snap the cable into the steering column
bracket so the retaining ears (Fig. 73) are engaged
and snap the cable eyelet onto the shift lever ball
stud.(4) Raise the vehicle.
(5) Place the transmission manual shift lever in
the ªPARKº detent (rearmost) position and rotate
prop shaft to ensure transmission is in PARK.
(6) Route the gearshift cable through the transmis-
sion mounting bracket and secure the cable by snap-
ping the cable retaining ears into the transmission
bracket and snapping the cable eyelet on the manual
shift lever ball stud.
(7) Lower vehicle.
(8) Lock the shift cable adjustment by pressing the
cable adjuster lock tab downward until it snaps into
place.
(9) Check for proper operation of the transmission
range sensor.
(10) Adjust the gearshift cable (Refer to 21 -
TRANSMISSION/AUTOMATIC/GEAR SHIFT
CABLE - ADJUSTMENTS) and BTSI mechanism
(Refer to 21 - TRANSMISSION/AUTOMATIC/
BRAKE TRANSMISSION SHIFT INTERLOCK SYS-
TEM - ADJUSTMENTS) as necessary.
ADJUSTMENTS
GEARSHIFT CABLE
Check adjustment by starting the engine in PARK
and NEUTRAL. Adjustment is CORRECT if the
engine starts only in these positions. Adjustment is
INCORRECT if the engine starts in one but not both
positions. If the engine starts in any position other
than PARK or NEUTRAL, or if the engine will not
start at all, the transmission range sensor may be
faulty.
Gearshift Adjustment Procedure
(1) Shift transmission into PARK.
(2) Release cable adjuster lock tab (underneath the
steering column) (Fig. 74) to unlock cable.
(3) Raise vehicle.
(4) Disengage the cable eyelet from the transmis-
sion manual shift lever.
(5) Verify transmission shift lever is in PARK
detent by moving lever fully rearward. Last rearward
detent is PARK position.
(6) Verify positive engagement of transmission
park lock by attempting to rotate propeller shaft.
Shaft will not rotate when park lock is engaged.
(7) Snap the cable eyelet onto the transmission
manual shift lever.
Fig. 72 Gearshift Cable at the Dash Panel
1 - GEARSHIFT CABLE
2 - GROMMET
Fig. 73 Gearshift Cable at Steering Column
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
21 - 370 AUTOMATIC TRANSMISSION - 45RFE/545RFEDR
GEARSHIFT CABLE (Continued)

(8) Lower vehicle.
(9) Lock shift cable by pressing cable adjuster lock
tab downward until it snaps into place.
(10) Check engine starting. Engine should start
only in PARK and NEUTRAL
HOLDING CLUTCHES
DESCRIPTION
Three hydraulically applied multi-disc clutches are
used to hold some planetary geartrain components
stationary while the input clutches drive others. The
2C, 4C, and Low/Reverse clutches are considered
holding clutches. The 2C and 4C clutches are located
in the 4C retainer/bulkhead (Fig. 75), while the Low/
Reverse clutch is located at the rear of the transmis-
sion case (Fig. 76).
Fig. 74 Gearshift Cable at Steering Column
1 - STEERING COLUMN
2 - GEARSHIFT CABLE
3 - GEARSHIFT CABLE LOCK TAB
4 - BTSI SOLENOID LOCK TAB
5 - BTSI CONNECTOR
Fig. 75 2C and 4C Clutches
1 - SEAL 8 - REACTION PLATE
2 - 2C PISTON 9 - SNAP-RING
3 - PLATE 10 - RETURN SPRING
4 - DISC 11 - SEAL
5 - 2C BELLEVILLE SPRING 12 - 4C PISTON
6 - SNAP-RING 13 - 4C RETAINER/BULKHEAD
7 - SNAP-RING (SELECT)
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 371
GEARSHIFT CABLE (Continued)

INPUT CLUTCH ASSEMBLY
DESCRIPTION
Three hydraulically applied input clutches are used
to drive planetary components. The underdrive, over-
drive, and reverse clutches are considered input
clutches and are contained within the input clutch
assembly (Fig. 77) and (Fig. 78). The input clutch
assembly also contains:
²Input shaft
²Input hub
²Clutch retainer
²Underdrive piston
²Overdrive/reverse piston²Overdrive hub
²Underdrive hubOPERATION
The three input clutches are responsible for driving
different components of the planetary geartrain.
UNDERDRIVE CLUTCH
The underdrive clutch is hydraulically applied in
first, second, second prime, and third (direct) gears
by pressurized fluid against the underdrive piston.
When the underdrive clutch is applied, the under-
drive hub drives the input sun gear.
Fig. 77 Input Clutch Assembly - Part 1
1 - INPUT CLUTCH HUB 11 - UD CLUTCH
2 - O-RING SEALS 12 - PLATE
3 - SEAL 13 - CLUTCH RETAINER
4 - SNAP-RING 14 - SEAL
5 - SNAP-RING 15 - OD/REV PISTON
6 - UD BALANCE PISTON 16 - BELLEVILLE SPRING
7 - SNAP-RING 17 - SNAP-RING
8 - UD PISTON 18 - SEAL RINGS
9 - SPRING 19 - INPUT SHAFT
10 - DISC 20 - LUBRICATION CHECK VALVE AND SNAP-RING
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 373

(6) Remove the number 3 bearing from the under-
drive hub.
(7) Remove the OD/reverse reaction plate snap-
ring from the input clutch retainer.
(8) Remove the underdrive hub, overdrive clutch,
and overdrive reaction plate from the input clutch
retainer (Fig. 79).
NOTE: The overdrive friction discs and steel discs
are thicker than the matching components in the
underdrive and reverse clutches.(9) Remove the number 2 bearing from the input
clutch hub.
(10) Remove the overdrive clutch wave snap-ring
from the input clutch retainer.
(11) Remove the UD/OD reaction plate tapered
snap-ring from the input clutch retainer.
(12) Remove the UD/OD reaction plate from the
input clutch retainer.
(13) Remove the UD/OD reaction plate flat snap-
ring from the input clutch retainer (Fig. 79).
(14) Remove the underdrive clutch pack from the
input clutch retainer (Fig. 81).
Fig. 79 Input Clutch Assembly - Part 2
1 - BEARING NUMBER 3 10 - SNAP-RING (SELECT)
2 - OD HUB/SHAFT 11 - PLATE
3 - SNAP-RING (WAVE) 12 - DISC
4 - REV/OD REACTION PLATE 13 - OD CLUTCH
5 - BEARING NUMBER 4 14 - SNAP-RING (TAPERED)
6 - SNAP-RING (FLAT) 15 - UD/OD REACTION PLATE
7 - REVERSE HUB/SHAFT 16 - SNAP-RING (FLAT)
8 - REVERSE CLUTCH 17 - UD HUB/SHAFT
9 - REVERSE REACTION PLATE 18 - BEARING NUMBER 2
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 375
INPUT CLUTCH ASSEMBLY (Continued)

ASSEMBLY
(1) Install all new seals and o-rings onto the input
shaft and input hub. The o-rings on the input hub
are color coded. Be sure to install the correct o-ring
in the correct location.
(2) Check the transmission lubrication check valve
located in the input shaft using shop air. The valve
should only allow air flow in one direction. If the
valve allows no air flow, or air flow in both direc-
tions, the valve will need to be replaced.(3) Lubricate all seals with MopartATF +4, Auto-
matic Transmission Fluid, prior to installation.
(4) Assemble the OD/reverse piston onto the input
clutch hub (Fig. 82).
(5) Assemble the input clutch retainer onto the
input clutch hub.
(6) Install the input clutch retainer tapered snap-
ring with tapered side up onto the input clutch hub.
Fig. 82 Input Clutch Assembly - Part I
1 - INPUT CLUTCH HUB 11 - UD CLUTCH
2 - O-RING SEALS 12 - PLATE
3 - SEAL 13 - CLUTCH RETAINER
4 - SNAP-RING 14 - SEAL
5 - SNAP-RING 15 - OD/REV PISTON
6 - UD BALANCE PISTON 16 - BELLEVILLE SPRING
7 - SNAP-RING 17 - SNAP-RING
8 - UD PISTON 18 - SEAL RINGS
9 - SPRING 19 - INPUT SHAFT
10 - DISC 20 - LUBRICATION CHECK VALVE AND SNAP-RING
21 - 378 AUTOMATIC TRANSMISSION - 45RFE/545RFEDR
INPUT CLUTCH ASSEMBLY (Continued)

feedback loop to the TCM. The TCM uses this infor-
mation to adjust its control of the pressure control
solenoid to achieve the desired line pressure.
OPERATION
The TCM calculates the desired line pressure
based upon inputs from the transmission and engine.
The TCM calculates the torque input to the trans-
mission and uses that information as the primary
input to the calculation. The line pressure is set to a
predetermined value during shifts and when the
transmission is in the PARK and NEUTRAL posi-
tions. This is done to ensure consistent shift quality.
During all other operation, the actual line pressure is
compared to the desired line pressure and adjust-
ments are made to the pressure control solenoid duty
cycle.
REMOVAL
(1) Raise vehicle.
(2) Place a suitable fluid catch pan under the
transmission.
(3) Remove the wiring connector from the line
pressure sensor (Fig. 92).
(4) Remove the bolt holding the line pressure sen-
sor to the transmission case.
(5) Remove the line pressure sensor from the
transmission case.
INSTALLATION
(1) Install the line pressure sensor into the trans-
mission case.(2) Install the bolt to hold the line pressure sensor
into the transmission case. Tighten the bolt to 11.9
N´m (105 in.lbs.).
(3) Install the wiring connector onto the line pres-
sure sensor
(4) Verify the transmission fluid level. Add fluid as
necessary.
(5) Lower vehicle.
Fig. 92 Line Pressure Sensor
1 - OUTPUT SPEED SENSOR
2 - LINE PRESSURE SENSOR
3 - INPUT SPEED SENSOR
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 383
LINE PRESSURE (LP) SENSOR (Continued)

(13) Measure the low/reverse clutch pack clearance
and adjust as necessary. The correct clutch clearance
is 1.00-1.74 mm (0.039-0.075 in.).
(14) Install the overrunning clutch into the low/re-
verse clutch retainer making sure that the index
splines are aligned with the retainer.
(15) Install the overrunning clutch inner snap-
ring.
OIL PUMP
DESCRIPTION
The oil pump (Fig. 96) is located at the front of the
transmission inside the bell housing and behind the
transmission front cover. The oil pump consists of
two independent pumps (Fig. 97), a number of valves
(Fig. 98), a front seal (Fig. 99), and a bolt on reaction
shaft. The converter clutch switch and regulator
valves, pressure regulator valve, and converter pres-
sure limit valve are all located in the oil pump valve
body.
OPERATION
As the torque converter rotates, the converter hub
rotates the oil pump drive gear. As the drive gear
rotates both driven gears, a vacuum is created when
the gear teeth come out of mesh. This suction draws
fluid through the pump inlet from the oil pan. As the
gear teeth come back into mesh, pressurized fluid is
forced into the pump outlet and to the oil pump
valves.
At low speeds, both sides of the pump supply fluid
to the transmission. As the speed of the torque con-verter increases, the flow from both sides increases
until the flow from the primary side alone is suffi-
cient to meet system demands. At this point, the
check valve located between the two pumps closes.
The secondary side is shut down and the primary
side supplies all the fluid to the transmission.
CONVERTER CLUTCH SWITCH VALVE
The converter clutch switch valve is used to control
the hydraulic pressure supplied to the front (OFF)
side of the torque converter clutch.
Fig. 96 Oil Pump
1 - OIL PUMP TO CASE BOLT (6)
2 - OIL PUMP
Fig. 97 Oil Pump Gears
1 - PUMP HOUSING
2 - DRIVE GEAR
3 - DRIVEN GEARS
Fig. 98 Oil Pump Valves
1 - TORQUE CONVERTER CLUTCH ACCUMULATOR VALVE
2 - TORQUE CONVERTER CLUTCH CONTROL VALVE
3 - TORQUE CONVERTER CLUTCH SWITCH VALVE
4 - PUMP VALVE BODY
5 - PRESSURE REGULATOR VALVE
6 - TORQUE CONVERTER CLUTCH LIMIT VALVE
21 - 386 AUTOMATIC TRANSMISSION - 45RFE/545RFEDR
LOW/REVERSE CLUTCH (Continued)