2001 DODGE RAM engine

FRONT CLUTCH
DESCRIPTION
The front clutch assembly (Fig. 84) is composed of
the front clutch retainer, pressure plate, clutch
plates, driving discs, piston, piston return spring,
return spring retainer, and snap-rings. The front
clutch is the forward-most component in the trans-
mission geartrain and is directly behind the oil pump
and is considered a driving component.
NOTE: The number of discs and plates may vary
with each engine and vehicle combination.
OPERATION
To apply the clutch, pressure is applied between
the clutch retainer and piston. The fluid pressure is
provided by the oil pump, transferred through the
control valves and passageways, and enters the
clutch through the hub of the reaction shaft support.
With pressure applied between the clutch retainer
and piston, the piston moves away from the clutch
retainer and compresses the clutch pack. This action
applies the clutch pack, allowing torque to flow
through the input shaft into the driving discs, and
into the clutch plates and pressure plate that are
lugged to the clutch retainer. The waved snap-ring is
used to cushion the application of the clutch pack.When pressure is released from the piston, the
spring returns the piston to its fully released position
and disengages the clutch. The release spring also
helps to cushion the application of the clutch assem-
bly. When the clutch is in the process of being
released by the release spring, fluid flows through a
vent and one-way ball-check-valve located in the
clutch retainer. The check-valve is needed to elimi-
nate the possibility of plate drag caused by centrifu-
gal force acting on the residual fluid trapped in the
clutch piston retainer.
DISASSEMBLY
(1) Remove waved snap-ring and remove pressure
plate, clutch plates and clutch discs (Fig. 85).
(2) Compress clutch piston spring with Compressor
Tool C-3575-A (Fig. 86). Be sure legs of tool are
seated squarely on spring retainer before compress-
ing spring.
(3) Remove retainer snap-ring and remove com-
pressor tool.
(4) Remove spring retainer and clutch spring. Note
position of retainer on spring for assembly reference.
(5) Remove clutch piston from clutch retainer.
Remove piston by rotating it up and out of retainer.
(6) Remove seals from clutch retainer piston bore
and clutch retainer hub. Discard both seals as they
are not reusable.
21 - 202 AUTOMATIC TRANSMISSION - 42REBR/BE

OPERATION
The application of the piston is accomplished by
applying pressure between the two lands of the pis-
ton. The pressure acts against the larger lower land
to push the piston downward, allowing the piston rod
to extend though its guide against the apply lever.
Release of the servo at the 2-3 upshift is accom-
plished by a combination of spring and line pressure,
acting on the bottom of the larger land of the piston.
The small piston is used to cushion the application of
the band by bleeding oil through a small orifice in
the larger piston. The release timing of the kickdown
servo is very important to obtain a smooth but firm
shift. The release has to be very quick, just as the
front clutch application is taking place. Otherwise,
engine runaway or a shift hesitation will occur. To
accomplish this, the band retains its holding capacity
until the front clutch is applied, giving a small
amount of overlap between them.
DISASSEMBLY
(1) Remove seal ring from rod guide (Fig. 92).
(2) Remove small snap-ring from servo piston rod.
Then remove piston rod, spring and washer from pis-
ton.
(3) Remove and discard servo component o-ring
and seal rings.
CLEANING
Clean the servo piston components (Fig. 93) with
solvent and dry them with compressed air.
INSPECTION
Inspect the servo components (Fig. 94). Replace the
springs if collapsed, distorted or broken. Replace the
guide, rod and piston if cracked, bent, or worn. Dis-
card the servo snap-ring if distorted or warped.
Check the servo piston bore for wear. If the bore is
severely scored, or damaged, it will be necessary to
replace the case.
Replace any servo component if doubt exists about
condition. Do not reuse suspect parts.
Fig. 92 Front Servo
1 - PISTON RINGS
2 - O-RING
3 - SNAP-RING
4 - SEAL RING
5 - PISTON ROD GUIDE
6 - SNAP-RING
7 - SERVO SPRING
8 - PISTON ROD
9 - SERVO PISTON
Fig. 93 Front Servo Piston
1 - PISTON RINGS
2 - O-RING
3 - SNAP-RING
4 - SEAL RING
5 - PISTON ROD GUIDE
6 - SNAP-RING
7 - SERVO SPRING
8 - PISTON ROD
9 - SERVO PISTON
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FRONT SERVO (Continued)

STANDARD PROCEDURE - OIL PUMP VOLUME
CHECK
Measuring the oil pump output volume will deter-
mine if sufficient oil flow to the transmission oil
cooler exists, and whether or not an internal trans-
mission failure is present.
Verify that the transmission fluid is at the proper
level. Refer to the Fluid Level Check procedure in
this section. If necessary, fill the transmission to the
proper level with MopartATF +4, type 9602, Auto-
matic Transmission Fluid.
(1) Disconnect theTo coolerline at the cooler
inlet and place a collecting container under the dis-
connected line.
CAUTION: With the fluid set at the proper level,
fluid collection should not exceed (1) quart or inter-
nal damage to the transmission may occur.
(2) Run the engineat curb idle speed, with the
shift selector in neutral.
(3) If one quart of transmission fluid is collected in
the container in 20 seconds or less, oil pump flow vol-
ume is within acceptable limits. If fluid flow is inter-
mittent, or it takes more than 20 seconds to collect
one quart of fluid, refer to the Hydraulic Pressure
tests in this section for further diagnosis.
(4) Re-connect theTo coolerline to the transmis-
sion cooler inlet.
(5) Refill the transmission to proper level.
DISASSEMBLY
(1) Remove seal ring from housing and reaction
shaft support (Fig. 98).
(2) Mark pump housing and support assembly for
alignment reference.
(3) Remove bolts attaching pump body to support
(Fig. 99).(4) Separate support from pump housing (Fig.
100).
Fig. 100 Separating Pump Housing From Reaction
Shaft Support
1 - REACTION SHAFT SUPPORT
2 - PUMP HOUSING
Fig. 98 Removing Pump Seal Ring
1 - PUMP HOUSING SEAL RING
Fig. 99 Pump Support Bolts
1 - REACTION SHAFT SUPPORT
2 - PUMP
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OIL PUMP (Continued)

OVERDRIVE CLUTCH
DESCRIPTION
The overdrive clutch (Fig. 113) is composed of the
pressure plate, clutch plates, holding discs, overdrive
piston retainer, piston, piston spacer, and snap-rings.
The overdrive clutch is the forwardmost component
in the transmission overdrive unit and is considered
a holding component. The overdrive piston retainer,piston, and piston spacer are located on the rear of
the main transmission case.
NOTE: The number of discs and plates may vary
with each engine and vehicle combination.
OPERATION
To apply the clutch, pressure is applied between
the piston retainer and piston. The fluid pressure is
provided by the oil pump, transferred through the
control valves and passageways, and enters the
clutch through passages at the lower rear portion of
the valve body area. With pressure applied between
the piston retainer and piston, the piston moves
away from the piston retainer and compresses the
clutch pack. This action applies the clutch pack,
allowing torque to flow through the intermediate
shaft into the overdrive planetary gear set. The over-
drive clutch discs are attached to the overdrive clutch
hub while the overdrive clutch plates, reaction plate,
and pressure plate are lugged to the overdrive hous-
ing. This allows the intermediate shaft to transfer
the engine torque to the planetary gear and overrun-
ning clutch. This drives the planetary gear inside the
annulus, which is attached to the overdrive clutch
drum and output shaft, creating the desired gear
ratio. The waved snap-ring is used to cushion the
application of the clutch pack.
Fig. 113 Overdrive Clutch
1 - REACTION PLATE 2 - PRESSURE PLATE
Fig. 112 Output Shaft Rear Bearing
1 - OUTPUT SHAFT REAR BEARING
2 - OVERDRIVE HOUSING
3 - SNAP-RING
21 - 214 AUTOMATIC TRANSMISSION - 42REBR/BE
OUTPUT SHAFT REAR BEARING (Continued)

REAR CLUTCH
DESCRIPTION
The rear clutch assembly (Fig. 215) 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.
OPERATION
To apply the clutch, pressure is applied between
the clutch retainer and piston. The fluid pressure is
provided by the oil pump, transferred through the
control valves and passageways, and enters the
clutch through the hub of the reaction shaft support.
With pressure applied between the clutch retainer
and piston, the piston moves away from the clutch
retainer and compresses the clutch pack. This action
applies the clutch pack, allowing torque to flow
through the input shaft into the driving discs, and
into the clutch plates and pressure plate that are
lugged to the clutch retainer. The waved spring is
used to cushion the application of the clutch pack.
The snap-ring is selective and used to adjust clutch
pack clearance.
When pressure is released from the piston, the
spring returns the piston to its fully released position
Fig. 215 Rear Clutch
1 - PISTON SPRING 10 - TOP PRESSURE PLATE
2 - REAR CLUTCH PISTON 11 - CLUTCH DISCS (4)
3 - CLUTCH PISTON SEALS 12 - BOTTOM PRESSURE PLATE
4 - OUTPUT SHAFT THRUST WASHER (METAL) 13 - WAVE SPRING
5 - INPUT SHAFT SNAP-RING 14 - CLUTCH PLATES (3)
6 - REAR CLUTCH RETAINER 15 - RETAINER SEAL RING
7 - INPUT SHAFT 16 - SHAFT REAR SEAL RING (PLASTIC)
8 - REAR CLUTCH THRUST WASHER (FIBER) 17 - SHAFT FRONT SEAL RING (TEFLON)
9 - CLUTCH PACK SNAP-RING (SELECTIVE)
21 - 246 AUTOMATIC TRANSMISSION - 42REBR/BE

No upshift to fourth gear will occur if any of the fol-
lowing are true:
²The transmission fluid temperature is below 10É
C (50É F) or above 121É C (250É F).
²The shift to third is not yet complete.
²Vehicle speed is too low for the 3-4 shift to occur.
²Battery temperature is below -5É C (23É F).
ADJUSTMENT
Check linkage adjustment by starting engine in
PARK and NEUTRAL. Adjustment is acceptable if
the engine starts in only these two positions. Adjust-
ment is incorrect if the engine starts in one position
but not both positions
If the engine starts in any other position, or if the
engine will not start in any position, the park/neutral
switch is probably faulty.
LINKAGE ADJUSTMENT
Check condition of the shift linkage (Fig. 227). Do
not attempt adjustment if any component is loose,
worn, or bent. Replace any suspect components.
Replace the grommet securing the shift rod or
torque rod in place if either rod was removed from
the grommet. Remove the old grommet as necessary
and use suitable pliers to install the new grommet.
(1) Shift transmission into PARK.
(2) Raise and support vehicle.
(3) Loosen lock bolt in front shift rod adjusting
swivel (Fig. 227).
(4) Ensure that the shift rod slides freely in the
swivel. Lube rod and swivel as necessary.
(5) Move transmission shift lever fully rearward to
the Park detent.
(6) Center adjusting swivel on shift rod.
(7) Tighten swivel lock bolt to 10 N´m (90 in. lbs.).
(8) Lower vehicle and verify proper adjustment.
SOLENOID
DESCRIPTION
The typical electrical solenoid used in automotive
applications is a linear actuator. It is a device that
produces motion in a straight line. This straight line
motion can be either forward or backward in direc-
tion, and short or long distance.
A solenoid is an electromechanical device that uses
a magnetic force to perform work. It consists of a coil
of wire, wrapped around a magnetic core made from
steel or iron, and a spring loaded, movable plunger,
which performs the work, or straight line motion.
The solenoids used in transmission applications
are attached to valves which can be classified asnor-
mally openornormally closed. Thenormally
opensolenoid valve is defined as a valve whichallows hydraulic flow when no current or voltage is
applied to the solenoid. Thenormally closedsole-
noid valve is defined as a valve which does not allow
hydraulic flow when no current or voltage is applied
to the solenoid. These valves perform hydraulic con-
trol functions for the transmission and must there-
fore be durable and tolerant of dirt particles. For
these reasons, the valves have hardened steel pop-
pets and ball valves. The solenoids operate the valves
directly, which means that the solenoids must have
very high outputs to close the valves against the siz-
able flow areas and line pressures found in current
transmissions. Fast response time is also necessary
to ensure accurate control of the transmission.
The strength of the magnetic field is the primary
force that determines the speed of operation in a par-
ticular solenoid design. A stronger magnetic field will
cause the plunger to move at a greater speed than a
weaker one. There are basically two ways to increase
the force of the magnetic field:
²Increase the amount of current applied to the
coil or
²Increase the number of turns of wire in the coil.
The most common practice is to increase the num-
ber of turns by using thin wire that can completely
fill the available space within the solenoid housing.
The strength of the spring and the length of the
Fig. 227 Linkage Adjustment Components
1 - FRONT SHIFT ROD
2 - TORQUE SHAFT ASSEMBLY
3 - TORQUE SHAFT ARM
4 - ADJUSTING SWIVEL
5 - LOCK BOLT
21 - 252 AUTOMATIC TRANSMISSION - 42REBR/BE
SHIFT MECHANISM (Continued)

plunger also contribute to the response speed possi-
ble by a particular solenoid design.
A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
SPEED SENSOR
DESCRIPTION
The speed sensor (Fig. 228) is located in the over-
drive gear case. The sensor is positioned over the
park gear and monitors transmission output shaft
rotating speed.
OPERATION
Speed sensor signals are triggered by the park
gear lugs as they rotate past the sensor pickup face.
Input signals from the sensor are sent to the trans-
mission control module for processing. Signals from
this sensor are shared with the powertrain control
module.
THROTTLE VALVE CABLE
DESCRIPTION
Transmission throttle valve cable (Fig. 229) adjust-
ment is extremely important to proper operation.
This adjustment positions the throttle valve, which
controls shift speed, quality, and part-throttle down-
shift sensitivity.
If cable setting is too loose, early shifts and slip-
page between shifts may occur. If the setting is too
tight, shifts may be delayed and part throttle down-
shifts may be very sensitive.
The transmission throttle valve is operated by a
cam on the throttle lever. The throttle lever is oper-
ated by an adjustable cable (Fig. 230). The cable is
attached to an arm mounted on the throttle lever
shaft. A retaining clip at the engine-end of the cable
Fig. 228 Transmission Output Speed Sensor
1 - TRANSMISSION OUTPUT SHAFT SPEED SENSOR
2 - SEAL
Fig. 229 Throttle Valve Cable Attachment - At
Engine
1 - THROTTLE VALVE CABLE
2 - CABLE BRACKET
3 - THROTTLE BODY LEVER
4 - ACCELERATOR CABLE
5 - SPEED CONTROL CABLE
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 253
SOLENOID (Continued)

is removed to provide for cable adjustment. The
retaining clip is then installed back onto the throttle
valve cable to lock in the adjustment.
ADJUSTMENTS - TRANSMISSION THROTTLE
VALVE CABLE
A correctly adjusted throttle valve cable will cause
the throttle lever on the transmission to move simul-
taneously with the throttle body lever from the idle
position. Proper adjustment will allow simultaneous
movement without causing the transmission throttle
lever to either move ahead of, or lag behind the lever
on the throttle body.
ADJUSTMENT VERIFICATION
(1) Turn ignition key to OFF position.
(2) Remove air cleaner.
(3) Verify that lever on throttle body is at curb idle
position (Fig. 231). Then verify that the transmission
throttle lever (Fig. 232) is also at idle (fully forward)
position.
(4) Slide cable off attachment stud on throttle body
lever.(5) Compare position of cable end to attachment
stud on throttle body lever:
²Cable end and attachment stud should be
aligned (or centered on one another) to within 1 mm
(0.039 in.) in either direction (Fig. 233).
²If cable end and attachment stud are misaligned
(off center), cable will have to be adjusted as
described in Throttle Valve Cable Adjustment proce-
dure.
(6) Reconnect cable end to attachment stud. Then
with aid of a helper, observe movement of transmis-
sion throttle lever and lever on throttle body.
²If both levers move simultaneously from idle to
half-throttle and back to idle position, adjustment is
correct.
²If transmission throttle lever moves ahead of, or
lags behind throttle body lever, cable adjustment will
be necessary. Or, if throttle body lever prevents
transmission lever from returning to closed position,
cable adjustment will be necessary.
Fig. 230 Throttle Valve Cable at Throttle Linkage
1 - THROTTLE LINKAGE
2 - THROTTLE VALVE CABLE LOCKING CLIP
3 - THROTTLE VALVE CABLE
Fig. 231 Throttle Valve Cable Attachment - At
Engine
1 - THROTTLE VALVE CABLE
2 - CABLE BRACKET
3 - THROTTLE BODY LEVER
4 - ACCELERATOR CABLE
5 - SPEED CONTROL CABLE
21 - 254 AUTOMATIC TRANSMISSION - 42REBR/BE
THROTTLE VALVE CABLE (Continued)