1998 DODGE RAM 1500 gear

INSTALLATION
(1) Be sure overdrive unit Alignment Tool 6227-2
is fully seated before moving unit. If tool is not
seated and gear splines rotate out of alignment, over-
drive unit will have to be disassembled in order to
realign splines.
(2) If overdrive piston retainer was not removed
during service and original case gasket is no longer
reusable, prepare new gasket by trimming it.
(3) Cut out old case gasket around piston retainer
with razor knife (Fig. 176).
(4) Use old gasket as template and trim new gas-
ket to fit.
(5) Position new gasket over piston retainer and
on transmission case. Use petroleum jelly to hold
gasket in place if necessary. Do not use any type of
sealer to secure gasket. Use petroleum jelly only.
(6) Install selective spacer on intermediate shaft, if
removed. Spacer goes in groove just rearward of
shaft rear splines (Fig. 177).
(7) Install thrust bearing in overdrive unit sliding
hub. Use petroleum jelly to hold bearing in position.
CAUTION: Be sure the shoulder on the inside diam-
eter of the bearing is facing forward.(8) Verify that splines in overdrive planetary gear
and overrunning clutch hub are aligned with Align-
ment Tool 6227-2. Overdrive unit cannot be installed
if splines are not aligned. If splines have rotated out
of alignment, unit will have to be disassembled to
realign splines.
(9) Carefully slide Alignment Tool 6227-2 out of
overdrive planetary gear and overrunning clutch
splines.
(10) Raise overdrive unit and carefully slide it
straight onto intermediate shaft. Insert park rod into
park lock reaction plug at same time. Avoid tilting
overdrive during installation as this could cause
planetary gear and overrunning clutch splines to
rotate out of alignment. If this occurs, it will be nec-
essary to remove and disassemble overdrive unit to
realign splines.
(11) Work overdrive unit forward on intermediate
shaft until seated against transmission case.
(12) Install bolts attaching overdrive unit to trans-
mission unit. Tighten bolts in diagonal pattern to 34
N´m (25 ft-lbs).
(13) Connect the transmission speed sensor and
overdrive wiring connectors.
(14) Install the transfer case, if equipped.
(15) Align and install rear propeller shaft, if nec-
essary. (Refer to 3 - DIFFERENTIAL & DRIVELINE/
PROPELLER SHAFT/PROPELLER SHAFT -
INSTALLATION)
Fig. 176 Trimming Overdrive Case Gasket
1 - GASKET
2 - SHARP KNIFE
Fig. 177 Intermediate Shaft Selective Spacer
Location
1 - SELECTIVE SPACER
2 - SPACER GROOVE
3 - INTERMEDIATE SHAFT
DRAUTOMATIC TRANSMISSION - 48RE 21 - 235
OVERDRIVE UNIT (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)

DISASSEMBLY
(1) Remove planetary snap-ring from intermediate
shaft (Fig. 193). Discard snap-ring as it is not reus-
able.
(2) Remove front planetary gear and front annulus
gear as assembly (Fig. 194).
(3) Remove front planetary gear and thrust
washer from front annulus gear (Fig. 195). Note
thrust washer position for assembly reference.
(4) Remove tabbed thrust washer from driving
shell (Fig. 196). Note washer position for assembly
reference.
Fig. 193 Removing Planetary Snap-Ring
1 - PLANETARY SNAP-RING
Fig. 194 Removing Front Planetary And Annulus
Gears
1 - DRIVING SHELL
2 - FRONT ANNULUS GEAR
3 - FRONT PLANETARY GEAR
Fig. 195 Disassembling Front Planetary And
Annulus Gears
1 - FRONT PLANETARY GEAR
2 - TABBED THRUST WASHER
3 - FRONT ANNULUS GEAR
4 - TORLON BUSHING
Fig. 196 Driving Shell Thrust Washer Removal
1 - DRIVING SHELL
2 - TABBED THRUST WASHER
3 - SUN GEAR
21 - 242 AUTOMATIC TRANSMISSION - 48REDR
PLANETARY GEARTRAIN/OUTPUT SHAFT (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)

thrust plate if worn, or severely scored. Replace the
driving shell if distorted, cracked, or damaged in any
way.
Replace all snap-rings during geartrain assembly.
Reusing snap-rings is not recommended.
ASSEMBLY
(1) Lubricate sun gear and planetary gears with
transmission fluid during assembly. Use petroleum
jelly to lubricate intermediate shaft bushing surfaces,
thrust washers and thrust plates and to hold these
parts in place during assembly.
(2) Install front snap-ring on sun gear and install
gear in driving shell. Then install thrust plate over
sun gear and against rear side of driving shell (Fig.
201). Install rear snap-ring to secure sun gear and
thrust plate in driving shell. Note that the large ID
chamfer on the sun gear goes forward.
(3) Install rear annulus gear on intermediate shaft
(Fig. 202).
(4) Install thrust washer to rear planetary gear
(Fig. 203) using petroleum jelly. Be sure washer is
seated against corner witht teh tabs completely in
the locating holes.
(5) Install rear planetary gear in rear annulus
gear (Fig. 204). Be sure planetary carrier is seated
against annulus gear.
Fig. 202 Installing Rear Annulus Gear On
Intermediate Shaft
1 - REAR ANNULUS GEAR
2 - OUTPUT SHAFT
Fig. 203 Installing Rear Annulus Thrust Washer
1 - REAR ANNULUS GEAR
2 - THRUST WASHER
Fig. 204 Installing Rear Planetary Gear
1 - REAR ANNULUS GEAR
2 - REAR PLANETARY GEAR
Fig. 201 Sun Gear Installation
1 - DRIVING SHELL
2 - SUN GEAR
3 - THRUST PLATE
4 - SUN GEAR REAR RETAINING RING
21 - 244 AUTOMATIC TRANSMISSION - 48REDR
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(6) Install tabbed thrust washer on front face of
rear planetary gear (Fig. 205). Seat washer tabs in
matching slots in face of gear carrier. Use extra
petroleum jelly to hold washer in place if desired.
(7) Lubricate sun gear bushings with petroleum
jelly or transmission fluid.
(8) Install sun gear and driving shell on interme-
diate shaft (Fig. 206). Seat shell against rear plane-
tary gear. Verify that thrust washer on planetary
gear was not displaced during installation.
(9) Install tabbed thrust washer in driving shell
(Fig. 207), be sure washer tabs are seated in tab slots
of driving shell. Use extra petroleum jelly to hold
washer in place if desired.
(10) Install tabbed thrust washer on front plane-
tary gear (Fig. 208). Seat washer tabs in matchingslots in face of gear carrier. Use extra petroleum jelly
to hold washer in place if desired.
(11) Install the torlon bushing onto the front plan-
etary carrier hub.
Fig. 205 Installing Rear Planetary Thrust Washer
1 - REAR PLANETARY GEAR
2 - TABBED THRUST WASHER
Fig. 206 Installing Sun Gear And Driving Shell
1 - OUTPUT SHAFT
2 - DRIVING SHELL
3 - REAR PLANETARY GEAR
4 - OUTPUT SHAFT
5 - SUN GEAR
Fig. 207 Installing Driving Shell Thrust Washer
1 - TAB SLOTS (3)
2 - DRIVING SHELL
3 - TABBED THRUST WASHER
Fig. 208 Installing Thrust Washer On Front
Planetary Gear
1 - TABBED THRUST WASHER
2 - FRONT PLANETARY GEAR
DRAUTOMATIC TRANSMISSION - 48RE 21 - 245
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)

(17) Check planetary geartrain end play with
feeler gauge (Fig. 212). Insert gauge between rear
annulus gear and shoulder on intermediate shaft as
shown. End play should be 0.15 to 1.22 mm (0.006 to
0.048 in.).
(18) If end play is incorrect, install thinner/thicker
planetary snap-ring as needed.
REAR CLUTCH
DESCRIPTION
The rear clutch assembly (Fig. 213) is composed of
the rear clutch retainer, pressure plate, clutch plates,
driving discs, piston, Belleville spring, and snap-
rings. The Belleville spring acts as a lever to multi-
ply the force applied on to it by the apply piston. The
increased apply force on the rear clutch pack, in com-
parison to the front clutch pack, is needed to hold
against the greater torque load imposed onto the rear
pack. The rear clutch is directly behind the front
clutch and is considered a driving component.NOTE: The number of discs and plates may vary
with each engine and vehicle combination.
Fig. 212 Checking Planetary Geartrain End Play
1 - OUTPUT SHAFT
2 - REAR ANNULUS GEAR
3 - FEELER GAUGE
Fig. 213 Rear Clutch Components
1 - REAR CLUTCH RETAINER 11 - REACTION PLATE
2 - TORLONŸ SEAL RINGS 12 - CLUTCH PLATES
3 - INPUT SHAFT 13 - WAVE SPRING
4 - PISTON RETAINER 14 - SPACER RING
5 - OUTPUT SHAFT THRUST WASHER 15 - PISTON
6 - INNER PISTON SEAL 16 - OUTER PISTON SEAL
7 - PISTON SPRING 17 - REAR SEAL RING
8 - PRESSURE PLATE 18 - FIBER THRUST WASHER
9 - CLUTCH DISCS 19 - RETAINING RING
10 - SNAP-RING (SELECTIVE)
DRAUTOMATIC TRANSMISSION - 48RE 21 - 247
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)