One DODGE RAM 1500 1998 2.G Workshop Manual

(10) Install planetary gear in annulus gear (Fig.
153). Be sure planetary pinions are fully seated in
annulus gear before proceeding.
(11) Coat planetary thrust bearing and bearing
contact surface of spring plate with generous amount
of petroleum jelly. This will help hold bearing in
place during installation.
(12) Install planetary thrust bearing on sun gear
(Fig. 154). Slide bearing onto gear and seat it against
spring plate as shown. Bearing fits one way only. If it
does not seat squarely against spring plate, remove
and reposition bearing.
(13) Install assembled sun gear, spring plate and
thrust bearing (Fig. 155). Be sure sun gear and
thrust bearing are fully seated before proceeding.(14) Mount assembled output shaft, annulus gear,
and clutch drum in shop press. Direct clutch spring,
hub and clutch pack are easier to install with assem-
bly mounted in press.
(15) Align splines in hubs of planetary gear and
overrunning clutch with Alignment tool 6227-2 (Fig.
156). Insert tool through sun gear and into splines of
both hubs. Be sure alignment tool is fully seated
before proceeding.
Fig. 156 Alignment Tool Installation
1 - SPECIAL TOOL 6227-2
2 - PRESS PLATES
3 - ASSEMBLED DRUM AND ANNULUS GEAR
4 - SUN GEAR
Fig. 153 Planetary Gear Installation
1 - PLANETARY GEAR
2 - ANNULUS GEAR
Fig. 154 Planetary Thrust Bearing Installation
1 - SPRING PLATE
2 - PLANETARY THRUST BEARING
3 - SUN GEAR
Fig. 155 Sun Gear Installation
1 - SUN GEAR AND SPRING PLATE ASSEMBLY
21 - 228 AUTOMATIC TRANSMISSION - 48REDR
OVERDRIVE UNIT (Continued)

(16) Install direct clutch spring (Fig. 157). Be sure
spring is properly seated on spring plate.
NOTE: The direct clutch in a 48RE transmission
uses 23 single-sided clutch discs.
(17) Assemble and install direct clutch pack on
hub as follows:
(a) Install direct clutch reaction plate on clutch
hub first. Note that one side of reaction plate is
counterbored. Be sure this side faces rearward.
Splines at rear of hub are raised slightly. Counter-
bore in plate fits over raised splines. Plate should
be flush with this end of hub (Fig. 158).(b) Install first clutch disc with internal splines
friction side up, followed by a disc with external
lugs friction side up. Continue alternating internal
and external discs until all discs have been
installed.
Fig. 158 Correct Position Of Direct Clutch Reaction
Plate
1-REACTION PLATE COUNTERBORE
2 - DIRECT CLUTCH REACTION PLATE (FLUSH WITH END OF HUB)
3 - CLUTCH HUB
Fig. 157 Direct Clutch Spring Installation
1 - SPECIAL TOOL 6227-2
2 - DIRECT CLUTCH SPRING
3 - CLUTCH HUB
4 - PRESS PLATES
DRAUTOMATIC TRANSMISSION - 48RE 21 - 229
OVERDRIVE UNIT (Continued)

(5) Install first clutch disc followed by first clutch
plate. Then install remaining clutch discs and plates
in same order.
(6) Install clutch pack pressure plate.
(7) Install clutch pack wire-type retaining ring
(Fig. 171).
INTERMEDIATE SHAFT SPACER SELECTION
(1) Place overdrive unit in vertical position. Mount
it on blocks, or in workbench with appropriate size
mounting hole cut into it. Be sure unit is facing
upward for access to direct clutch hub. Also be sure
output shaft is not loaded and internal components
are moved rearward for accurate measurement.
(2) Determine correct thickness intermediate shaft
spacer as follows:
(a) Insert Special Tool 6312 through sun gear,
planetary gear and into pilot bushing in output
shaft. Be sure tool bottoms against planetary
shoulder.
(b) Position Gauge Tool 6311 across face of over-
drive case (Fig. 172). Then position Dial Caliper
C-4962 over gauge tool.(c) Extend sliding scale of dial caliper downward
through gauge tool slot until scale contacts end of
Gauge Alignment Tool 6312. Lock scale in place.
Remove dial caliper tool and note distance mea-
sured (Fig. 172).
(d) Select proper thickness end play spacer from
spacer chart based on distance measured (Fig.
173).
(e) Remove Gauge Alignment Tool 6312.
Fig. 171 Overdrive Clutch Pack Retaining Ring
Installation
1 - OVERDRIVE CLUTCH PACK RETAINING RINGFig. 172 Shaft End Play Measurement
1 - SPECIAL TOOL 6312
2 - SPECIAL TOOL 6311
3 - SPECIAL TOOL C-4962
Fig. 173 Intermediate Shaft End Play Spacer
Selection
DRAUTOMATIC TRANSMISSION - 48RE 21 - 233
OVERDRIVE UNIT (Continued)

OD THRUST PLATE SELECTION
(1) Place overdrive unit in vertical position. Mount
it on blocks, or in workbench with appropriate size
mounting hole cut into it. Be sure unit is facing
upward for access to direct clutch hub. Also be sure
output shaft is not loaded and internal components
are moved rearward for accurate measurement.
(2) Determine correct thickness overdrive piston
thrust plate as follows:
(a) Position Gauge Tool 6311 across face of over-
drive case. Then position Dial Caliper C-4962 over
gauge tool (Fig. 174).
(b) Measure distance to clutch hub thrust bear-
ing seat at four points 90É apart. Then average
measurements by adding them and dividing by 4.
(c) Select and install required thrust plate from
information in thrust plate chart (Fig. 175).
(3) Leave Alignment Tool 6227-2 in place. Tool will
keep planetary and clutch hub splines in alignment
until overdrive unit is ready for installation on trans-
mission.
(4) Transmission speed sensor can be installed at
this time if desired. However, it is recommended that
sensor not be installed until after overdrive unit is
secured to transmission.
OVERDRIVE PISTON
(1) Install new seals on overdrive piston.
(2) Stand transmission case upright on bellhous-
ing.
(3) Position Guide Ring 8114-1 on outer edge of
overdrive piston retainer.
(4) Position Seal Guide 8114-3 on inner edge of
overdrive piston retainer.
(5) Install overdrive piston in overdrive piston
retainer by:
(a) Aligning locating lugs on overdrive piston to
the two mating holes in retainer.
(b) Lubricate overdrive piston seals with Mopart
ATF+4.
(c) Install piston over Seal Guide 8114-3 and
inside Guide Ring 8114-1.
(d) Push overdrive piston into position in
retainer.
(e) Verify that the locating lugs entered the lug
bores in the retainer.
(6) Install intermediate shaft spacer on intermedi-
ate shaft.
(7) Install overdrive piston thrust plate on over-
drive piston.
(8) Install overdrive piston thrust bearing on over-
drive piston.
(9) Install transmission speed sensor and o-ring
seal in overdrive case.
Fig. 174 Overdrive Piston Thrust Plate Measurement
1 - SPECIAL TOOL 6311
2 - DIRECT CLUTCH HUB THRUST BEARING SEAT
3 - SPECIAL TOOL C-4962
Fig. 175 Overdrive Piston Thrust Plate Selection
21 - 234 AUTOMATIC TRANSMISSION - 48REDR
OVERDRIVE UNIT (Continued)

OVERRUNNING CLUTCH
CAM/OVERDRIVE PISTON
RETAINER
DESCRIPTION
The overrunning clutch (Fig. 178) consists of an
inner race, an outer race (or cam), rollers and
springs, and the spring retainer. The number of roll-
ers and springs depends on what transmission and
which overrunning clutch is being dealt with.
OPERATION
As the inner race is rotated in a clockwise direction
(as viewed from the front of the transmission), the
race causes the rollers to roll toward the springs,
causing them to compress against their retainer. The
compression of the springs increases the clearance
between the rollers and cam. This increased clear-
ance between the rollers and cam results in a free-
wheeling condition. When the inner race attempts to
rotate counterclockwise, the action causes the rollers
to roll in the same direction as the race, aided by the
pushing of the springs. As the rollers try to move in
the same direction as the inner race, they are
wedged between the inner and outer races due to the
design of the cam. In this condition, the clutch is
locked and acts as one unit.
DISASSEMBLY
(1) Remove the overdrive piston (Fig. 179).
(2) Remove the overdrive piston retainer bolts.
(3) Remove overdrive piston retainer.
(4) Remove case gasket.(5) Tap old cam out of case with pin punch. Insert
punch through bolt holes at rear of case (Fig. 180).
Alternate position of punch to avoid cocking cam dur-
ing removal.
(6) Clean clutch cam bore and case. Be sure to
remove all chips/shavings generated during cam
removal.
CLEANING
Clean the overrunning clutch assembly, clutch cam,
low-reverse drum, and overdrive piston retainer in
solvent. Dry them with compressed air after clean-
ing.
Fig. 178 Overrunning Clutch
1 - OUTER RACE (CAM)
2 - ROLLER
3 - SPRING
4 - SPRING RETAINER
5 - INNER RACE (HUB)
Fig. 179 Overdrive Piston Removal
1 - OVERDRIVE CLUTCH PISTON
2 - INTERMEDIATE SHAFT
3 - SELECTIVE SPACER
4 - PISTON RETAINER
Fig. 180 Overrunning Clutch Cam
1 - PIN PUNCH
2 - REAR SUPPORT BOLT HOLES
21 - 236 AUTOMATIC TRANSMISSION - 48REDR

INSPECTION
Inspect condition of each clutch part after cleaning.
Replace the overrunning clutch roller and spring
assembly if any rollers or springs are worn or dam-
aged, or if the roller cage is distorted, or damaged.
Replace the cam if worn, cracked or damaged.
Replace the low-reverse drum if the clutch race,
roller surface or inside diameter is scored, worn or
damaged.Do not remove the clutch race from
the low-reverse drum under any circumstances.
Replace the drum and race as an assembly if
either component is damaged.
Examine the overdrive piston retainer carefully for
wear, cracks, scoring or other damage. Be sure the
retainer hub is a snug fit in the case and drum.
Replace the retainer if worn or damaged.
ASSEMBLY
(1) Temporarily install overdrive piston retainer in
case. Use 3-4 bolts to secure retainer.
(2) Align and start new clutch cam in the trans-
mission case. Be sure serrations on cam and in case
are aligned (Fig. 181). Then tap cam into case just
enough to hold it in place.
(3) Verify that cam is correctly positioned before
proceeding any further. Narrow ends of cam ramps
should be to left when cam is viewed from front end
of case (Fig. 181).
(4) Insert Adapter Tool SP-5124 from Installer/Re-
mover C-3863-A into piston retainer (Fig. 182).
(5) Assemble Puller Bolt SP-3701 and Press Plate
SP-3583-A (Fig. 183).
Fig. 181 Positioning Replacement Clutch Cam In
Case
1 - ALIGN SERRATIONS ON CAM AND IN CASE
2 - CLUTCH CAM
Fig. 182 Positioning Adapter Tool In Overdrive
Piston Retainer
1 - PISTON RETAINER
2 - SPECIAL TOOL SP-5124
Fig. 183 Assembling Clutch Cam Puller Bolt And
Press Plate
1 - PULLER BOLT SP-3701
2 - PRESS PLATE SP-3583-A
DRAUTOMATIC TRANSMISSION - 48RE 21 - 237
OVERRUNNING CLUTCH CAM/OVERDRIVE PISTON RETAINER (Continued)

(14) Position overdrive piston retainer on trans-
mission case and align bolt holes in retainer, gasket
and case (Fig. 187). Then install and tighten retainer
bolts to 17 N´m (13 ft. lbs.) torque.
(15) Install new seals on overdrive piston.
(16) Stand transmission case upright on bellhous-
ing.
(17) Position Guide Ring 8114-1 on outer edge of
overdrive piston retainer.
(18) Position Seal Guide 8114-3 on inner edge of
overdrive piston retainer.
(19) Install overdrive piston in overdrive piston
retainer by: aligning locating lugs on overdrive piston
to the two mating holes in retainer.
(a) Aligning locating lugs on overdrive piston to
the two mating holes in retainer.
(b) Lubricate overdrive piston seals with Mopart
Door Ease, or equivalent.
(c) Install piston over Seal Guide 8114-3 and
inside Guide Ring 8114-1.
(d) Push overdrive piston into position in
retainer.
(e) Verify that the locating lugs entered the lug
bores in the retainer.PISTONS
DESCRIPTION
There are several sizes and types of pistons used in
an automatic transmission. Some pistons are used to
apply clutches, while others are used to apply bands.
They all have in common the fact that they are
round or circular in shape, located within a smooth
walled cylinder, which is closed at one end and con-
verts fluid pressure into mechanical movement. The
fluid pressure exerted on the piston is contained
within the system through the use of piston rings or
seals.
OPERATION
The principal which makes this operation possible
is known as Pascal's Law. Pascal's Law can be stated
as: ªPressure on a confined fluid is transmitted
equally in all directions and acts with equal force on
equal areas.º
PRESSURE
Pressure (Fig. 188) is nothing more than force
(lbs.) divided by area (in or ft.), or force per unit
area. Given a 100 lb. block and an area of 100 sq. in.
on the floor, the pressure exerted by the block is: 100
lbs. 100 in or 1 pound per square inch, or PSI as it is
commonly referred to.
Fig. 187 Aligning Overdrive Piston Retainer
1 - PISTON RETAINER
2 - GASKET
3 - RETAINER BOLTS
Fig. 188 Force and Pressure Relationship
DRAUTOMATIC TRANSMISSION - 48RE 21 - 239
OVERRUNNING CLUTCH CAM/OVERDRIVE PISTON RETAINER (Continued)

PISTON TRAVEL
The relationship between hydraulic lever and a
mechanical lever is the same. With a mechanical
lever it's a weight-to-distance output rather than a
pressure-to-area output. Using the same forces and
areas as in the previous example, the smaller piston
(Fig. 191) has to move ten times the distance
required to move the larger piston one inch. There-
fore, for every inch the larger piston moves, the
smaller piston moves ten inches. This principle is
true in other instances also. A common garage floor
jack is a good example. To raise a car weighing 2000
lbs., an effort of only 100 lbs. may be required. For
every inch the car moves upward, the input piston at
the jack handle must move 20 inches downward.
PLANETARY GEARTRAIN/
OUTPUT SHAFT
DESCRIPTION
The planetary gearsets (Fig. 192) are designated as
the front, rear, and overdrive planetary gear assem-
blies and located in such order. A simple planetary
gearset consists of three main members:²The sun gear which is at the center of the sys-
tem.
²The planet carrier with planet pinion gears
which are free to rotate on their own shafts and are
in mesh with the sun gear.
²The annulus gear, which rotates around and is
in mesh with the planet pinion gears.
NOTE: The number of pinion gears does not affect
the gear ratio, only the duty rating.
OPERATION
With any given planetary gearset, several condi-
tions must be met for power to be able to flow:
²One member must be held.
²Another member must be driven or used as an
input.
²The third member may be used as an output for
power flow.
²For direct drive to occur, two gear members in
the front planetary gearset must be driven.
NOTE: Gear ratios are dependent on the number of
teeth on the annulus and sun gears.
Fig. 191 Piston Travel
Fig. 192 Planetary Gearset
1 - ANNULUS GEAR
2 - SUN GEAR
3 - PLANET CARRIER
4 - PLANET PINIONS (4)
DRAUTOMATIC TRANSMISSION - 48RE 21 - 241
PISTONS (Continued)

(5) Remove sun gear and driving shell as assembly
(Fig. 197).
(6) Remove tabbed thrust washer from rear plane-
tary gear (Fig. 198). Note washer position on gear for
assembly reference.
(7) Remove rear planetary gear and rear annulus
gear from intermediate shaft (Fig. 199).
(8) Remove thrust washer from rear planetary
gear (Fig. 200).
INSPECTION
Inspect the planetary gear sets and annulus gears.
The planetary pinions, shafts, washers, and retaining
pins are serviceable. However, if a pinion carrier is
damaged, the entire planetary gear set must be
replaced as an assembly.Replace the annulus gears if the teeth are chipped,
broken, or worn, or the gear is cracked. Replace the
planetary thrust plates and the tabbed thrust wash-
ers if cracked, scored or worn.
Inspect the machined surfaces of the intermediate
shaft. Be sure the oil passages are open and clear.
Replace the shaft if scored, pitted, or damaged.
Inspect the sun gear and driving shell. If either
component is worn or damaged, remove the sun gear
rear retaining ring and separate the sun gear and
thrust plate from the driving shell. Then replace the
necessary component.
Replace the sun gear as an assembly if the gear
teeth are chipped or worn. Also replace the gear as
an assembly if the bushings are scored or worn. The
sun gear bushings are not serviceable. Replace the
Fig. 197 Sun Gear And Driving Shell Removal
1 - INTERMEDIATE SHAFT
2 - DRIVING SHELL
3 - SUN GEAR
Fig. 198 Rear Planetary Thrust Washer Removal
1 - SUN GEAR
2 - REAR PLANETARY THRUST WASHER
3 - DRIVING SHELL
Fig. 199 Rear Planetary And Annulus Gear Removal
1 - INTERMEDIATE SHAFT
2 - REAR ANNULUS GEAR
3 - REAR PLANETARY GEAR
Fig. 200 Rear Annulus Thrust Washer Removal
1 - REAR ANNULUS GEAR
2 - THRUST WASHER
DRAUTOMATIC TRANSMISSION - 48RE 21 - 243
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(12) Install front annulus gear over and onto front
planetary gear (Fig. 209). Be sure gears are fully
meshed and seated.
(13) Install front planetary and annulus gear
assembly (Fig. 210). Hold gears together and slide
them onto shaft. Be sure planetary pinions are
seated on sun gear and that planetary carrier is
seated on intermediate shaft.
(14) Place geartrain in upright position. Rotate
gears to be sure all components are seated and prop-
erly assembled. Snap-ring groove at forward end of
intermediate shaft will be completely exposed when
components are assembled correctly.
(15) Install new planetary snap-ring in groove at
end of intermediate shaft (Fig. 211).
(16) Turn planetary geartrain over. Position wood
block under front end of intermediate shaft and sup-
port geartrain on shaft. Be sure all geartrain parts
have moved forward against planetary snap-ring.
This is important for accurate end play check.
Fig. 209 Assembling Front Planetary And
Annulus Gears
1 - FRONT ANNULUS GEAR
2 - FRONT PLANETARY GEAR
Fig. 210 Installing Front Planetary And Annulus
Gear Assembly
1 - DRIVING SHELL
2 - ASSEMBLED FRONT PLANETARY AND ANNULUS GEARS
Fig. 211 Installing Planetary Snap
1 - SNAP-RING PLIERS
2 - PLANETARY SNAP-RING
21 - 246 AUTOMATIC TRANSMISSION - 48REDR
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)