DODGE RAM 2001 Service Repair Manual

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.
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) Examine bolt holes in overrunning clutch cam.
Note that one hole isnot threaded(Fig. 184). This
hole must align with blank area in clutch cam bolt
circle (Fig. 185). Mark hole location on clutch cam
and blank area in case with grease pencil, paint
stripe, or scribe mark for assembly reference.
(2) Mark location of non-threaded hole in clutch
cam and blank area in bolt circle with grease pencil.
(3) Align and install overrunning clutch and cam
in case (Fig. 186). Be sure cam is correctly installed.
Bolt holes in cam are slightly countersunk on oneside. Be sure this side of cam faces rearward (toward
piston retainer).
(4) Verify that non-threaded hole in clutch cam is
properly aligned. Check alignment by threading a
bolt into each bolt hole. Adjust clutch cam position if
necessary.
(5) Install and tighten overrunning clutch cam
bolts to 17 N´m (13 ft. lbs.) torque. Note that clutch
cam bolts are shorter than piston retainer bolts.
(6) Install new gasket at rear of transmission case.
Use petroleum jelly to hold gasket in place. Be sure
to align governor feed holes in gasket with feed pas-
sages in case (Fig. 187). Also install gasket before
Fig. 184 Location Of Non-Threaded Hole In Clutch
Cam
1 - NON-THREADED HOLE
2 - OVERRUNNING CLUTCH CAM
Fig. 185 Location Of Blank Area In Clutch Cam Bolt
Circle
1 - OVERRUNNING CLUTCH CAM SEAT IN CASE
2 - NON-THREADED HOLE IN CLUTCH CAM ALIGNS HERE
(BLANK AREA) OF SEAT
Fig. 186 Overrunning Clutch Installation
1 - ALIGN MARKS IDENTIFYING NON-THREADED HOLE IN
CAM AND CASE
2 - OVERRUNNING CLUTCH ASSEMBLY
21 - 236 AUTOMATIC TRANSMISSION - 42REBR/BE
OVERRUNNING CLUTCH CAM/OVERDRIVE PISTON RETAINER (Continued)

overdrive piston retainer. Center hole in gasket is
smaller than retainer and cannot be installed over
retainer.
(7) Position overdrive piston retainer on transmis-
sion case and align bolt holes in retainer, gasket and
case (Fig. 188). Then install and tighten retainer
bolts to 17 N´m (13 ft. lbs.) torque.
(8) Install new seals on over drive piston.
(9) Stand transmission case upright on bellhous-
ing.
(10) Position Guide Ring 8114-1 on outer edge of
overdrive piston retainer.
(11) Position Seal Guide 8114-2 on inner edge of
overdrive piston retainer.
(12) 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 8114-2 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.NOTE: Install the remaining transmission compo-
nents and the overdrive unit.
PARK/NEUTRAL POSITION
SWITCH
DIAGNOSIS AND TESTING - PARK/NEUTRAL
POSITION SWITCH
The center terminal of the park/neutral position
switch is the starter-circuit terminal. It provides the
ground for the starter solenoid circuit through the
selector lever in PARK and NEUTRAL positions only.
The outer terminals on the switch are for the backup
lamp circuit.
SWITCH TEST
To test the switch, remove the wiring connector.
Test for continuity between the center terminal and
the transmission case. Continuity should exist only
when the transmission is in PARK or NEUTRAL.
Shift the transmission into REVERSE and test
continuity at the switch outer terminals. Continuity
should exist only when the transmission is in
REVERSE. Continuity should not exist between the
outer terminals and the case.
Check gearshift linkage adjustment before replac-
ing a switch that tests faulty.
Fig. 187 Installing/Aligning Case Gasket
1 - CASE GASKET
2 - BE SURE GOVERNOR TUBE FEED HOLES IN CASE AND
GASKET ARE ALIGNED
Fig. 188 Aligning Overdrive Piston Retainer
1 - PISTON RETAINER
2 - GASKET
3 - RETAINER BOLTS
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 237
OVERRUNNING CLUTCH CAM/OVERDRIVE PISTON RETAINER (Continued)

REMOVAL
(1) Raise vehicle and position drain pan under
switch.
(2) Disconnect switch wires.
(3) Remove switch from case.
INSTALLATION
(1) Move shift lever to PARK and NEUTRAL posi-
tions. Verify that switch operating lever fingers are
centered in switch opening in case (Fig. 189).
(2) Install new seal on switch and install switch in
case. Tighten switch to 34 N´m (25 ft. lbs.) torque.
(3) Test continuity of new switch with 12V test
lamp.
(4) Connect switch wires and lower vehicle.
(5) Top off transmission fluid level.
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. 190) 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.
PRESSURE ON A CONFINED FLUID
Pressure is exerted on a confined fluid (Fig. 191)
by applying a force to some given area in contact
with the fluid. A good example of this is a cylinder
filled with fluid and equipped with a piston that is
closely fitted to the cylinder wall. If a force is applied
to the piston, pressure will be developed in the fluid.
Of course, no pressure will be created if the fluid is
not confined. It will simply ªleakº past the piston.
There must be a resistance to flow in order to create
pressure. Piston sealing is extremely important in
hydraulic operation. Several kinds of seals are used
to accomplish this within a transmission. These
include but are not limited to O-rings, D-rings, lip
seals, sealing rings, or extremely close tolerances
between the piston and the cylinder wall. The force
exerted is downward (gravity), however, the principle
remains the same no matter which direction is taken.
Fig. 189 Park/Neutral Position Switch
1 - NEUTRAL CONTACT
2 - MANUAL LEVER AND SWITCH PLUNGER IN REVERSE
POSITION
3 - PARK CONTACT
4 - SWITCH
Fig. 190 Force and Pressure Relationship
21 - 238 AUTOMATIC TRANSMISSION - 42REBR/BE
PARK/NEUTRAL POSITION SWITCH (Continued)

The pressure created in the fluid is equal to the force
applied, divided by the piston area. If the force is 100
lbs., and the piston area is 10 sq. in., then the pres-
sure created equals 10 PSI. Another interpretation of
Pascal's Law is that regardless of container shape or
size, the pressure will be maintained throughout, as
long as the fluid is confined. In other words, the
pressure in the fluid is the same everywhere within
the container.
FORCE MULTIPLICATION
Using the 10 PSI example used in the illustration
(Fig. 192), a force of 1000 lbs. can be moved with a
force of only 100 lbs. The secret of force multiplica-
tion in hydraulic systems is the total fluid contact
area employed. The illustration, (Fig. 192), shows an
area that is ten times larger than the original area.
The pressure created with the smaller 100 lb. input
is 10 PSI. The concept ªpressure is the same every-
whereº means that the pressure underneath the
larger piston is also 10 PSI. Pressure is equal to the
force applied divided by the contact area. Therefore,
by means of simple algebra, the output force may be
found. This concept is extremely important, as it is
also used in the design and operation of all shift
valves and limiting valves in the valve body, as well
as the pistons, of the transmission, which activate
the clutches and bands. It is nothing more than
using a difference of area to create a difference in
pressure to move an object.
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. 193) 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.
Fig. 191 Pressure on a Confined Fluid
Fig. 192 Force Multiplication
Fig. 193 Piston Travel
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 239
PISTONS (Continued)

PLANETARY GEARTRAIN/
OUTPUT SHAFT
DESCRIPTION
The planetary gearsets (Fig. 194) 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.
DISASSEMBLY
(1) Remove planetary snap-ring (Fig. 195).
(2) Remove front annulus and planetary assembly
from driving shell (Fig. 195).
(3) Remove snap-ring that retains front planetary
gear in annulus gear (Fig. 196).
Fig. 195 Front Annulus And Planetary Assembly
Removal
1 - DRIVING SHELL
2 - FRONT ANNULUS AND PLANETARY ASSEMBLY
3 - PLANETARY SNAP-RING
Fig. 196 Front Planetary Snap-Ring Removal
1 - FRONT ANNULUS GEAR
2 - PLANETARY SNAP-RING
Fig. 194 Planetary Gearset
1 - ANNULUS GEAR
2 - SUN GEAR
3 - PLANET CARRIER
4 - PLANET PINIONS (4)
21 - 240 AUTOMATIC TRANSMISSION - 42REBR/BE

(4) Remove tabbed thrust washer and tabbed
thrust plate from hub of front annulus (Fig. 197).
(5) Separate front annulus and planetary gears
(Fig. 197).
(6) Remove front planetary gear front thrust
washer from annulus gear hub.
(7) Separate and remove driving shell, rear plane-
tary and rear annulus from output shaft (Fig. 198).
(8) Remove front planetary rear thrust washer
from driving shell.
(9) Remove tabbed thrust washers from rear plan-
etary gear.
(10) Remove lock ring that retains sun gear in
driving shell. Then remove sun gear, spacer and
thrust plates.
INSPECTION
Check sun gear and driving shell condition.
Replace the gear if damaged or if the bushings are
scored or worn. The bushings are not serviceable.
Replace the driving shell if worn, cracked or dam-
aged.
Replace planetary gear sets if gears, pinion pins, or
carrier are damaged in any way. Replace the annulus
gears and supports if either component is worn or
damaged.
Inspect the geartrain spacers, thrust plates, snap-
rings, and thrust washers. Replace any of these parts
that are worn, distorted or damaged. Do not attempt
to reuse these parts.
The planetary gear thrust washers are different
sizes. The large diameter washers go on the front
planetary and the smaller washers go on the rear
planetary. All the washers have four locating tabs onthem. These tabs fit in the holes or slots provided in
each planetary gear.
Inspect the output shaft carefully. Pay particular
attention to the machined bushing/bearing surfaces
on the shaft and the governor valve shaft bore at the
shaft rear.
Replace the output shaft if the machined surfaces
are scored, pitted, or damaged in any way. Also
replace the shaft if the splines are damaged, or
exhibits cracks at any location (especially at the gov-
ernor valve shaft bore).
The annulus gears can be removed from their sup-
ports if necessary. Just remove the snap-rings and
separate the two parts when replacement is neces-
sary. In addition, the annulus gear bushings can be
replaced if severely worn, or scored. However it is not
necessary to replace the bushings if they only exhibit
normal wear. Check bushing fit on the output shaft
to be sure.
ASSEMBLY
(1) Lubricate output shaft and planetary compo-
nents with transmission fluid. Use petroleum jelly to
lubricate and hold thrust washers and plates in posi-
tion.
(2) Assemble rear annulus gear and support if dis-
assembled. Be sure support snap-ring is seated and
that shoulder-side of support faces rearward (Fig.
199).
(3) Install rear thrust washer on rear planetary
gear. Use enough petroleum jelly to hold washer in
place. Also be sure all four washer tabs are properly
engaged in gear slots.
(4) Install rear annulus over and onto rear plane-
tary gear (Fig. 199).
Fig. 197 Front Planetary And Annulus
Gear Disassembly
1 - FRONT ANNULUS
2 - THRUST WASHER
3 - THRUST PLATE
4 - FRONT THRUST WASHER
5 - FRONT PLANETARY
Fig. 198 Removing Driving Shell, Rear Planetary
And Rear Annulus
1 - REAR ANNULUS
2 - REAR PLANETARY
3 - DRIVING SHELL
4 - OUTPUT SHAFT
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 241
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(5) Install assembled rear planetary and annulus
gear on output shaft (Fig. 200). Verify that assembly
is fully seated on shaft.
(6) Install front thrust washer on rear planetary
gear (Fig. 201). Use enough petroleum jelly to hold
washer on gear. Be sure all four washer tabs are
seated in slots.
(7) Install spacer on sun gear (Fig. 202).
(8) Install thrust plate on sun gear (Fig. 203). Note
that driving shell thrust plates are interchangeable.
Use either plate on sun gear and at front/rear of
shell.
Fig. 199 Assembling Rear Annulus And Planetary
Gear
1 - REAR ANNULUS GEAR
2 - TABBED THRUST WASHER
3 - REAR PLANETARY
Fig. 200 Installing Rear Annulus And Planetary On
Output Shaft
1 - REAR ANNULUS AND PLANETARY GEAR ASSEMBLY
2 - OUTPUT SHAFT
Fig. 201 Installing Rear Planetary Front Thrust
Washer
1 - FRONT TABBED THRUST WASHER
2 - REAR PLANETARY GEAR
Fig. 202 Installing Spacer On Sun Gear
1 - SUN GEAR
2 - SUN GEAR SPACER
Fig. 203 Installing Driving Shell Front Thrust Plate
On Sun Gear
1 - SPACER
2 - SUN GEAR
3 - THRUST PLATE
21 - 242 AUTOMATIC TRANSMISSION - 42REBR/BE
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(9) Hold sun gear in place and install thrust plate
over sun gear at rear of driving shell (Fig. 204).
(10) Position wood block on bench and support sun
gear on block (Fig. 205). This makes it easier to align
and install sun gear lock ring. Keep wood block
handy as it will also be used for geartrain end play
check.(11) Align rear thrust plate on driving shell and
install sun gear lock ring. Be sure ring is fully seated
in sun gear ring groove (Fig. 206).
(12) Install assembled driving shell and sun gear
on output shaft (Fig. 207).
Fig. 204 Installing Driving Shell Rear Thrust Plate
1 - DRIVING SHELL
2 - SUN GEAR
3 - REAR THRUST PLATE
Fig. 205 Supporting Sun Gear On Wood Block
1 - SUN GEAR
2 - DRIVING SHELL
3 - WOOD BLOCK
Fig. 206 Installing Sun Gear Lock Ring
1 - LOCK RING GROOVE
2 - SUN GEAR LOCK RING
3 - DRIVING SHELL
4 - REAR THRUST PLATE
Fig. 207 Installing Assembled Sun Gear And Driving
Shell On Output Shaft
1 - SUN GEAR/DRIVING SHELL ASSEMBLY
2 - OUTPUT SHAFT
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 243
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(13) Install rear thrust washer on front planetary
gear (Fig. 208). Use enough petroleum jelly to hold
washer in place and be sure all four washer tabs are
seated.
(14) Install front planetary gear on output shaft
and in driving shell (Fig. 209).
(15) Install front thrust washer on front planetary
gear. Use enough petroleum jelly to hold washer in
place and be sure all four washer tabs are seated.
(16) Assemble front annulus gear and support, if
necessary. Be sure support snap-ring is seated.(17) Install front annulus on front planetary (Fig.
209).
(18) Position thrust plate on front annulus gear
support (Fig. 210). Note that plate has two tabs on it.
These tabs fit in notches of annulus hub.
(19) Install thrust washer in front annulus (Fig.
211). Align flat on washer with flat on planetary hub.
Also be sure washer tab is facing up.
Fig. 209 Installing Front Planetary And Annulus
Gears
1 - FRONT PLANETARY GEAR
2 - FRONT THRUST WASHER
3 - FRONT ANNULUS GEAR
Fig. 210 Positioning Thrust Plate On Front Annulus
Support
1 - FRONT ANNULUS
2 - THRUST PLATE
Fig. 211 Installing Front Annulus Thrust Washer
1 - WASHER FLAT ALIGNS WITH FLAT ON PLANETARY HUB
2 - FRONT ANNULUS THRUST WASHER
3 - TAB FACES FRONT
Fig. 208 Installing Rear Thrust Washer On Front
Planetary Gear
1 - FRONT PLANETARY GEAR
2 - REAR TABBED THRUST WASHER
21 - 244 AUTOMATIC TRANSMISSION - 42REBR/BE
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)

(20) Install front annulus snap-ring (Fig. 212). Use
snap-ring pliers to avoid distorting ring during
installation. Also be sure ring is fully seated.
(21) Install planetary selective snap-ring with
snap-ring pliers (Fig. 213). Be sure ring is fully
seated.
(22) Turn planetary geartrain assembly over so
driving shell is facing workbench. Then support
geartrain on wood block positioned under forward
end of output shaft. This allows geartrain compo-
nents to move forward for accurate end play check.
(23) Check planetary geartrain end play with
feeler gauge (Fig. 214). Gauge goes between shoulder
on output shaft and end of rear annulus support.
(24) Geartrain end play should be 0.12 to 1.22 mm
(0.005 to 0.048 in.). If end play is incorrect, snap-ring
(or thrust washers) may have to be replaced. Snap-
rings are available in three different thicknesses for
adjustment purposes.
Fig. 212 Installing Front Annulus Snap-Ring
1 - SNAP-RING PLIERS
2 - FRONT ANNULUS SNAP-RING
Fig. 213 Installing Planetary Selective Snap-Ring
1 - SELECTIVE SNAP-RING
2 - SNAP-RING PLIERS
Fig. 214 Checking Planetary Geartrain End Play
1 - OUTPUT SHAFT
2 - REAR ANNULUS GEAR
3 - FEELER GAUGE
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 245
PLANETARY GEARTRAIN/OUTPUT SHAFT (Continued)