1998 DODGE RAM 1500 Lubrication

INSTALLATION
NOTE: If a new transmission is being installed, use
all components supplied with the new transmission.
For example, if a new shift tower is supplied, do not
re-use the original shift tower.
(1) Clean transmission front housing mounting
surface.
(2) Apply light coat of Mopar high temperature
bearing grease or equivalent to contact surfaces (Fig.
126) of following components:
²release fork ball stud.
²release bearing slide surface.
²input shaft splines.
²release bearing bore.
²propeller shaft slip yoke.
(3) Support and secure transmission to jack.
(4) Raise and align transmission input shaft with
clutch disc, then slide transmission into place.
(5) Verify front housing is fully seated. Install
transmission bolts without washers and tighten bolts
into the engine to 41 N´m (30 ft. lbs.). Tighten the
bolts with washers into the transmission to 68 N´m
(50 ft. lbs.) (Fig. 127).(6) Install rear crossmember and tighten nuts to
102 N´m (75 ft. lbs.).
(7) Install transmission rear mounting bolts and
tighten to 68 N´m (50 ft. lbs.).
(8) Install front dust shield tighten bolt to 4.5 N´m
(40 in. lbs.). If cover was removed, install onto the
transmission and engine(Refer to 9 - ENGINE/EN-
GINE BLOCK/STRUCTURAL COVER - INSTALLA-
TION).
(9) Install structural dust cover and tighten the
bolts to 54 N´m (40 ft. lbs.).
(10) Install starter motor.
(11) Install suspension crossmember and tighten
nuts to 102 N´m (75 ft. lbs.).
(12) Connect transmission harnesses to clips on
case and connect switches.
(13) Install slave cylinder and tighten cylinder
nuts to 23 N´m (200 in. lbs.).
(14) Install transfer case and transfer case linkage
if equipped.
(15) Remove transmission jack.
(16) Install propeller shaft/shafts with reference
marks aligned.
(17) Install exhaust on the exhaust manifolds.
(18) Fill transmission with lubricant. Correct fill
level is to bottom edge of fill plug hole.
Fig. 126 LUBRICATION POINTS
1 - RELEASE FORK
2 - FORK BALL STUD
3 - BEARING SLIDE SURFACE
4 - SPLINE
5 - RELEASE BEAING
Fig. 127 TRANSMISSION
1 - BOLT WITHOUT WASHER
2 - BOLT WITH WASHER
DRMANUAL TRANSMISSION - NV3500 21 - 39
MANUAL TRANSMISSION - NV3500 (Continued)

AUTOMATIC TRANSMISSION -
48RE
DESCRIPTION
The 48RE (Fig. 1) is a four speed fully automatic
transmissions with an electronic governor. The 48RE
is equipped with a lock-up clutch in the torque con-
verter. First through third gear ranges are provided
by the clutches, bands, overrunning clutch, and plan-
etary gear sets in the transmission. Fourth gear
range is provided by the overdrive unit that contains
an overdrive clutch, direct clutch, planetary gear set,
and overrunning clutch.
The transmission contains a front, rear, and direct
clutch which function as the input driving compo-
nents. It also contains the kickdown (front) and thelow/reverse (rear) bands which, along with the over-
running clutch and overdrive clutch, serve as the
holding components. The driving and holding compo-
nents combine to select the necessary planetary gear
components, in the front, rear, or overdrive planetary
gear set, transfer the engine power from the input
shaft through to the output shaft.
The valve body is mounted to the lower side of the
transmission and contains the valves to control pres-
sure regulation, fluid flow control, and clutch/band
application. The oil pump is mounted at the front of
the transmission and is driven by the torque con-
verter hub. The pump supplies the oil pressure nec-
essary for clutch/band actuation and transmission
lubrication.
21 - 132 AUTOMATIC TRANSMISSION - 48REDR

(3) Have helper start and run engine at 1600 rpm
for test.
(4)
Move transmission shift lever four detents rear-
ward from full forward position. This is Reverse range.
(5) Move transmission throttle lever fully forward
then fully rearward and note reading at Gauge
C-3293-SP.
(6) Pressure should be 145 - 175 psi (1000-1207
kPa) with throttle lever forward and increase to 230 -
280 psi (1586-1931 kPa) as lever is gradually moved
rearward.
Test Five - Governor Pressure
This test checks governor operation by measuring
governor pressure response to changes in vehicle
speed. It is usually not necessary to check governor
operation unless shift speeds are incorrect or if the
transmission will not downshift. The test should be
performed on the road or on a hoist that will allow
the rear wheels to rotate freely.
(1) Move 100 psi Test Gauge C-3292 to governor
pressure port.
(2) Move transmission shift lever two detents rear-
ward from full forward position. This is D range.
(3) Have helper start and run engine at curb idle
speed. Then firmly apply service brakes so wheels
will not rotate.
(4) Note governor pressure:
²
Governor pressure should be no more than 20.6
kPa (3 psi) at curb idle speed and wheels not rotating.
²If pressure exceeds 20.6 kPa (3 psi), a fault
exists in governor pressure control system.
(5) Release brakes, slowly increase engine speed,
and observe speedometer and pressure test gauge (do
not exceed 30 mph on speedometer). Governor pres-
sure should increase in proportion to vehicle speed.
Or approximately 6.89 kPa (1 psi) for every 1 mph.
(6) Governor pressure rise should be smooth and
drop back to no more than 20.6 kPa (3 psi), after
engine returns to curb idle and brakes are applied to
prevent wheels from rotating.
(7)
Compare results of pressure test with analysis
chart.
Test Six - Transmission In Overdrive Fourth Gear
This test checks line pressure at the overdrive
clutch in fourth gear range. Use 300 psi Test Gauge
C-3293-SP for this test. The test should be performed
on the road or on a chassis dyno.
(1)
Remove tachometer; it is not needed for this test.
(2) Move 300 psi Gauge to overdrive clutch pres-
sure test port. Then remove other gauge and reinstall
test port plug.
(3) Lower vehicle.
(4) Turn OD switch on.(5) Secure test gauge so it can be viewed from
drivers seat.
(6) Start engine and shift into D range.
(7) Increase vehicle speed gradually until 3-4 shift
occurs and note gauge pressure.
(8) Pressure should be 524-565 kPa (76-82 psi)
with closed throttle and increase to 690-896 kPa
(100-130 psi) at 1/2 to 3/4 throttle. Note that pres-
sure can increase to around 965 kPa (140 psi) at full
throttle.
(9) Return to shop or move vehicle off chassis
dyno.
PRESSURE TEST ANALYSIS CHART
TEST CONDITION INDICATION
Line pressure OK during
any one testPump and regulator
valve OK
Line pressure OK in R
but low in D, 2, 1Leakage in rear clutch
area (seal rings, clutch
seals)
Pressure low in D Fourth
Gear RangeOverdrive clutch piston
seal, or check ball
problem
Pressure OK in 1, 2 but
low in D3 and RLeakage in front clutch
area
Pressure OK in 2 but low
in R and 1Leakage in rear servo
Front servo pressure in 2 Leakage in servo; broken
servo ring or cracked
servo piston
Pressure low in all
positionsClogged filter, stuck
regulator valve, worn or
faulty pump, low oil level
Governor pressure too
high at idle speedGovernor pressure
solenoid valve system
fault. Refer to diagnostic
book.
Governor pressure low at
all mph figuresFaulty governor pressure
solenoid, transmission
control module, or
governor pressure
sensor
Lubrication pressure low
at all throttle positionsClogged fluid cooler or
lines, seal rings leaking,
worn pump bushings,
pump, clutch retainer, or
clogged filter.
Line pressure high Output shaft plugged,
sticky regulator valve
Line pressure low Sticky regulator valve,
clogged filter, worn pump
DRAUTOMATIC TRANSMISSION - 48RE 21 - 143
AUTOMATIC TRANSMISSION - 48RE (Continued)

pressure is ªmeteredº out into the circuits and viewed
as throttle pressure. This increased throttle pressure
is metered out into the circuits it is applied to: the
1-2 and 2-3 shift valves. When the throttle pressure
is high enough, a 3-2 downshift will occur. If the
vehicle speed is low enough, a 2-1 downshift will
occur.
SWITCH VALVE
When the transmission is in Drive Second before
the TCC application occurs (Fig. 268), the pressure
regulator valve is supplying torque converter pres-
sure to the switch valve. The switch valve directs
this pressure through the transmission input shaft,
into the converter, through the converter, back outbetween the input shaft and the reaction shaft, and
back up to the switch valve. From the switch valve,
the fluid pressure is directed to the transmission
cooler, and lubrication pressure returns from the
cooler to lubricate different portions of the transmis-
sion.
Fig. 268 Switch Valve - Torque Converter Unlocked
DRAUTOMATIC TRANSMISSION - 48RE 21 - 283
VALVE BODY (Continued)

Once the TCC control valve has moved to the right
(Fig. 269), line pressure is directed to the tip of the
switch valve, forcing the valve to the right. The
switch valve now vents oil from the front of the pis-
ton in the torque converter, and supplies line pres-
sure to the (rear) apply side of the torque converter
piston. This pressure differential causes the piston to
apply against the friction material, cutting off any
further flow of line pressure oil. After the switch
valve is shuttled right allowing line pressure to
engage the TCC, torque converter pressure is
directed past the switch valve into the transmission
cooler and lubrication circuits.
Fig. 269 Switch Valve - Torque Converter Locked
21 - 284 AUTOMATIC TRANSMISSION - 48REDR
VALVE BODY (Continued)

TRANSMISSION IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan
sealing surface (Fig. 1). Refer to this information
when ordering replacement parts. A label is attached
to the transmission case above the stamped numbers.
The label gives additional information which may
also be necessary for identification purposes.
GEAR RATIOS
The 45RFE gear ratios are:
1st .................................3.00:1
2nd.................................1.67:1
2nd Prime...........................1.50:1
3rd.................................1.00:1
4th .................................0.75:1
Reverse.............................3.00:1
GEAR RATIOS
The 545RFE gear ratios are:
1st .................................3.00:1
2nd.................................1.67:1
2nd Prime...........................1.50:1
3rd.................................1.00:1
4th .................................0.75:1
5th .................................0.67:1
Reverse.............................3.00:1
OPERATION
The 45RFE/545RFE offers full electronic control of
all automatic up and downshifts, and features real-
time adaptive closed-loop shift and pressure control.
Electronic shift and torque converter clutch controls
help protect the transmission from damage due to
high temperatures, which can occur under severe
operating conditions. By altering shift schedules, line
pressure, and converter clutch control, these controls
reduce heat generation and increase transmission
cooling.
To help reduce efficiency-robbing parasitic losses,
the transmissions includes a dual-stage transmission
fluid pump with electronic output pressure control.
Under most driving conditions, pump output pres-
sure greatly exceeds that which is needed to keep the
clutches applied. The 45RFE/545RFE pump-pressure
control system monitors input torque and adjusts the
pump pressure accordingly. The primary stage of the
pump works continuously; the second stage is
bypassed when demand is low. The control system
also monitors input and output speed and, if incipi-
ent clutch slip is observed, the pressure control sole-
noid duty cycle is varied, increasing pressure in
proportion to demand.
A high-travel torque converter damper assembly
allows earlier torque converter clutch engagement to
reduce slippage. Needle-type thrust bearings reduce
internal friction. The 45RFE/545RFE is packaged in
a one-piece die-cast aluminum case. To reduce NVH,
the case has high lateral, vertical and torsional stiff-
ness. It is also designed to maximize the benefit of
the structural dust cover that connects the bottom of
the bell housing to the engine bedplate, enhancing
overall power train stiffness. Dual filters protect the
pump and other components. A pump return filter is
added to the customary main sump filter. Indepen-
dent lubrication and cooler circuits assure ample
pressure for normal transmission operation even if
the cooler is obstructed or the fluid cannot flow due
to extremely low temperatures.
The hydraulic control system design (without elec-
tronic assist) provides the transmission with PARK,
REVERSE, NEUTRAL, SECOND, and THIRD gears,
based solely on driver shift lever selection. This
design allows the vehicle to be driven (in ªlimp-inº
mode) in the event of a electronic control system fail-
ure, or a situation that the Transmission Control
Module (TCM) recognizes as potentially damaging to
the transmission.
The TCM also performs certain self-diagnostic
functions and provides comprehensive information
(sensor data, DTC's, etc.) which is helpful in proper
diagnosis and repair. This information can be viewed
with the DRBtscan tool.
Fig. 1 Transmission Part And Serial Number
Location
1 - IDENTIFICATION NUMBERS (STAMPED)
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 313
AUTOMATIC TRANSMISSION - 45RFE/545RFE (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

Fig. 81 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 - 377
INPUT CLUTCH ASSEMBLY (Continued)