2003 JEEP GRAND CHEROKEE bore

CONDITION POSSIBLE CAUSES CORRECTION
CLUNK NOISE FROM
DRIVELINE ON
CLOSED THROTTLE
4-3 DOWNSHIFT1. Transmission Fluid Low. 1. Add Fluid.
2. Throttle Cable Mis-adjusted. 2. Adjust cable.
3. Overdrive Clutch Select Spacer
Wrong Spacer.3. Replace overdrive piston thrust plate spacer.
3-4 UPSHIFT
OCCURS
IMMEDIATELY AFTER
2-3 SHIFT1. Overdrive Solenoid Connector or
Wiring Shorted.1.
Test connector and wiring for loose connections,
shorts or ground and repair as needed.
2. TPS Malfunction. 2. Test TPS and replace as necessary. Check with
DRBTscan tool.
3. PCM Malfunction. 3. Test PCM with DRBTscan tool and replace
controller if faulty.
4. Overdrive Solenoid Malfunction. 4. Replace solenoid.
5. Valve Body Malfunction. 5. Remove, disassemble, clean and inspect valve
body components. Make sure all valves and plugs
slide freely in bores. Polish valves with crocus
cloth if needed.
WHINE/NOISE
RELATED TO ENGINE
SPEED1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Shift Cable Incorrect Routing. 2. Check shift cable for correct routing. Should not
touch engine or bell housing.
NO 3-4 UPSHIFT 1. O/D Switch In OFF Position. 1. Turn control switch to ON position.
2. Overdrive Circuit Fuse Blown. 2. Replace fuse. Determine why fuse failed and
repair as necessary (i.e., shorts or grounds in
circuit).
3. O/D Switch Wire Shorted/Open
Cut.3. Check wires/connections with 12V test lamp
and voltmeter. Repair damaged or loose
wire/connection as necessary.
4. Distance or Coolant Sensor
Malfunction.4. Check with DRBTscan tool and repair or
replace as necessary.
5. TPS Malfunction. 5. Check with DRBTscan tool and replace if
necessary.
6. Neutral Sense to PCM Wire
Shorted/Cut.6. Test switch/sensor as described in service
section and replace if necessary. Engine no start.
7. PCM Malfunction. 7. Check with DRBTscan tool and replace if
necessary.
8. Overdrive Solenoid Shorted/
Open.8. Replace solenoid if shorted or open and repair
loose or damaged wires (DRBTscan tool).
9. Solenoid Feed Orifice in Valve
Body Blocked.9. Remove, disassemble, and clean valve body
thoroughly. Check feed orifice.
10. Overdrive Clutch Failed. 10. Disassemble overdrive and repair as needed.
11. Hydraulic Pressure Low. 11. Pressure test transmission to determine
cause.
12. Valve Body Valve Stuck. 12. Repair stuck 3-4 shift valve, 3-4 timing valve.
13. O/D Piston Incorrect Spacer. 13. Remove unit, check end play and install
correct spacer.
14. Overdrive Piston Seal Failure. 14. Replace both seals.
15. O/D Check Valve/Orifice Failed. 15. Check for free movement and secure
assembly (in piston retainer). Check ball bleed
orifice.
WJAUTOMATIC TRANSMISSION - 42RE 21 - 23
AUTOMATIC TRANSMISSION - 42RE (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
SLIPS IN OVERDRIVE
FOURTH GEAR1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Overdrive Clutch Pack Worn. 2. Remove overdrive unit and rebuild clutch pack.
3. Overdrive Piston Retainer Bleed
Orifice Blown Out.3. Disassemble transmission, remove retainer and
replace orifice.
4. Overdrive Piston or Seal
Malfunction.4. Remove overdrive unit. Replace seals if worn.
Replace piston if damaged. If piston retainer is
damaged, remove and disassemble the
transmission.
5. 3-4 Shift Valve, Timing Valve or
Accumulator Malfunction.5. Remove and overhaul valve body. Replace
accumulator seals. Make sure all valves operate
freely in bores and do not bind or stick. Make sure
valve body screws are correctly tightened and
separator plates are properly positioned.
6. Overdrive Unit Thrust Bearing
Failure.6. Disassemble overdrive unit and replace thrust
bearing (NO. 1 thrust bearing is between
overdrive piston and clutch hub; NO. 2 thrust
bearing is between the planetary gear and the
direct clutch spring plate; NO. 3 thrust bearing is
between overrunning clutch hub and output shaft).
7. O/D Check Valve/Bleed Orifice
Failure.7. Check for function/secure orifice insert in O/D
piston retainer.
DELAYED 3-4
UPSHIFT (SLOW TO
ENGAGE)1. Fluid Level Low. 1. Add fluid and check for leaks.
2. Throttle Valve Cable Mis-
adjusted.2. Adjust throttle valve cable.
3. Overdrive Clutch Pack
Worn/Burnt.3. Remove unit and rebuild clutch pack.
4. TPS Faulty. 4. Test with DRBTscan tool and replace as
necessary
5. Overdrive Clutch Bleed Orifice
Plugged.5. Disassemble transmission and replace orifice.
6. Overdrive Solenoid or Wiring
Shorted/Open.6. Test solenoid and check wiring for loose/
corroded connections or shorts/grounds. Replace
solenoid if faulty and repair wiring if necessary.
7. Overdrive Excess Clearance. 7. Remove unit. Measure end play and select
proper spacer.
8. O/D Check Valve Missing or
Stuck.8. Check for presence of check valve. Repair or
replace as required.
TORQUE
CONVERTER LOCKS
UP IN SECOND
AND/OR THIRD
GEARLockup Solenoid, Relay or Wiring
Shorted/Open.Test solenoid, relay and wiring for continuity,
shorts or grounds. Replace solenoid and relay if
faulty. Repair wiring and connectors as necessary.
HARSH 1-2, 2-3, 3-4
OR 3-2 SHIFTSLockup Solenoid Malfunction. Remove valve body and replace solenoid
assembly.
21 - 24 AUTOMATIC TRANSMISSION - 42REWJ
AUTOMATIC TRANSMISSION - 42RE (Continued)

(29) Loosen rear band adjusting screw 4-5 turns.
(30) Remove low-reverse drum snap-ring (Fig. 35).(31) Remove low-reverse drum and reverse band.
(32) Remove overrunning clutch roller and spring
assembly as a unit (Fig. 36).
(33) Compress front servo rod guide about 1/8 inch
with Valve Spring Compressor C-3422-B (Fig. 37).
(34) Remove front servo rod guide snap-ring. Exer-
cise caution when removing snap-ring. Servo bore
can be scratched or nicked if care is not exercised.
(35) Remove compressor tools and remove front
servo rod guide, spring and servo piston.
Fig. 34 Removing Planetary Geartrain And
Intermediate Shaft Assembly
1 - PLANETARY GEARTRAIN AND INTERMEDIATE SHAFT
ASSEMBLY
Fig. 35 Removing Low-Reverse Drum Snap-Ring
1 - LOW-REVERSE DRUM
2 - HUB OF OVERDRIVE PISTON RETAINER
3 - LOW-REVERSE DRUM SNAP-RING
Fig. 36 Overrunning Clutch Assembly Removal
1 - OVERRUNNING CLUTCH CAM
2 - REAR BAND REACTION PIN
3 - OVERRUNNING CLUTCH ASSEMBLY
Fig. 37 Compressing Front Servo Rod Guide
1 - SPRING COMPRESSOR TOOL C-3422-B
2 - ROD GUIDE SNAP-RING
WJAUTOMATIC TRANSMISSION - 42RE 21 - 33
AUTOMATIC TRANSMISSION - 42RE (Continued)

(36) Compress rear servo spring retainer about
1/16 inch with Valve Spring Compressor C-3422-B
(Fig. 38).
(37) Remove rear servo spring retainer snap-ring.
Then remove compressor tools and remove rear servo
spring and piston.
(38) Inspect transmission components.
NOTE: To Service the overrunning clutch cam or
overdrive piston retainer, refer to the Overrunning
Clutch Cam service procedure in this section.
CLEANING
Clean the case in a solvent tank. Flush the case
bores and fluid passages thoroughly with solvent.
Dry the case and all fluid passages with compressed
air. Be sure all solvent is removed from the case and
that all fluid passages are clear.
NOTE: Do not use shop towels or rags to dry the
case (or any other transmission component) unless
they are made from lint-free materials. Lint will stick
to case surfaces and transmission components and
circulate throughout the transmission after assem-
bly. A sufficient quantity of lint can block fluid pas-
sages and interfere with valve body operation.Lubricate transmission parts with MopartATF +4,
type 9602, transmission fluid during overhaul and
assembly. Use petroleum jelly, MopartDoor Ease, or
Ru-GlydeŸ to prelubricate seals, O-rings, and thrust
washers. Petroleum jelly can also be used to hold
parts in place during reassembly.
INSPECTION
Inspect the case for cracks, porous spots, worn
bores, or damaged threads. Damaged threads can be
repaired with Helicoil thread inserts. However, the
case will have to be replaced if it exhibits any type of
damage or wear.
Lubricate the front band adjusting screw threads
with petroleum jelly and thread the screw part-way
into the case. Be sure the screw turns freely.
Inspect the transmission bushings during overhaul.
Bushing condition is important as worn, scored bush-
ings contribute to low pressures, clutch slip and
accelerated wear of other components. However, do
not replace bushings as a matter of course. Replace
bushings only when they are actually worn, or
scored.
Use recommended tools to replace bushings. The
tools are sized and designed to remove, install, and
seat bushings correctly. The bushing replacement
tools are included in Bushing Tool Set C-3887-B.
Pre-sized service bushings are available for
replacement purposes. Only the sun gear bushings
are not serviced.
The use of crocus cloth is permissible where neces-
sary, providing it is used carefully. When used on
shafts, or valves, use extreme care to avoid rounding
off sharp edges. Sharp edges are vital as they pre-
vent foreign matter from getting between the valve
and valve bore.
Do not reuse oil seals, gaskets, seal rings, or
O-rings during overhaul. Replace these parts as a
matter of course. Also do not reuse snap rings or
E-clips that are bent or distorted. Replace these parts
as well.
ASSEMBLY
Do not allow dirt, grease, or foreign material to
enter the case or transmission components during
assembly. Keep the transmission case and compo-
nents clean. Also make sure the tools and workbench
area used for assembly operations are equally clean.
Shop towels used for wiping off tools and hands
must be made fromlint freematerial. Lint will stick
to transmission parts and could interfere with valve
operation, or even restrict fluid passages.
Lubricate the transmission components with
Moparttransmission fluid during reassembly. Use
MopartDoor Ease, or Ru-GlydeŸ on seals and
O-rings to ease installation.
Fig. 38 Compressing Rear Servo Spring
1 - FRONT SERVO SNAP-RING
2 - REAR SERVO SNAP-RING
3 - SPECIAL TOOL
21 - 34 AUTOMATIC TRANSMISSION - 42REWJ
AUTOMATIC TRANSMISSION - 42RE (Continued)

(e) Turn drum back and forth. Drum should
rotate freely in clockwise direction and lock in
counterclockwise direction (as viewed from front of
case).(7) Install snap-ring that secures low-reverse drum
to hub of overdrive piston retainer (Fig. 44).
(8) Install rear band lever and pivot pin (Fig. 45).
Align lever with pin bores in case and push pivot pin
into place.
(9) Install planetary geartrain assembly (Fig. 46).
Fig. 42 Rear Band Installation
1 - REAR BAND
Fig. 43 Installing Low-Reverse Drum
1 - REAR BAND
2 - LOW-REVERSE DRUM
Fig. 44 Installing Low-Reverse Drum Retaining
Snap-Ring
1 - LOW-REVERSE DRUM
2 - HUB OF OVERDRIVE PISTON RETAINER
3 - LOW-REVERSE DRUM SNAP-RING
Fig. 45 Rear Band Lever And Pivot Pin Installation
1 - REAR BAND LEVER
2 - LEVER PIVOT PIN
21 - 36 AUTOMATIC TRANSMISSION - 42REWJ
AUTOMATIC TRANSMISSION - 42RE (Continued)

(23) Check seal rings on reaction shaft support
hub. Verify that seal rings are hooked together and
that the thrust washer is properly positioned (Fig.
55). Use petroleum jelly to hold thrust washer in
place if necessary.(24) Lubricate oil pump body seal with petroleum
jelly. Lubricate pump shaft seal lip with petroleum
jelly.
(25) Thread two Pilot Stud Tools C-3288-B into
bolt holes in oil pump bore flange (Fig. 56).
(26) Align and install oil pump gasket (Fig. 56).
Fig. 53 Installing Front/Rear Clutch Assemblies
1 - INPUT SHAFT
2 - FRONT CLUTCH
3 - REAR CLUTCH
Fig. 54 Front Band Linkage Installation
1 - BAND LEVER
2 - BAND STRUT
3 - FRONT BAND
Fig. 55 Reaction Shaft Support Seal Rings And
Thrust Washer
1 - REACTION SHAFT SUPPORT HUB
2 - THRUST WASHER
3 - SEAL RINGS
Fig. 56 Installing Pilot Studs And Oil Pump Gasket
1 - OIL PUMP GASKET
2 - PILOT STUD TOOLS C-3288-B
WJAUTOMATIC TRANSMISSION - 42RE 21 - 39
AUTOMATIC TRANSMISSION - 42RE (Continued)

ACCUMULATOR
DESCRIPTION
The accumulator (Fig. 62) is a hydraulic device
that has the sole purpose of cushioning the applica-
tion of a band or clutch. The accumulator consists of
a dual-land piston and a spring located in a bore in
the transmission case. The 3-4 accumulator is located
in a housing attached to the side of the valve body
(Fig. 63).
OPERATION
Both the accumulator and the 3-4 accumulator
function the same. Line pressure is directed to the
small end of the piston when the transmission is
placed into a DRIVE position (Fig. 64), bottoming it
against the accumulator plate. When the 1-2 upshift
occurs (Fig. 65), line pressure is directed to the large
end of the piston and then to the kickdown servo. As
the line pressure reaches the accumulator, the com-
bination of spring pressure and line pressure forces
the piston away from the accumulator plate. This
causes a balanced pressure situation, which results
in a cushioned band application. After the kickdown
servo has become immovable, line pressure will fin-
ish pushing the accumulator up into its bore. When
the large end of the accumulator piston is seated in
its bore, the band or clutch is fully applied.
NOTE: The accumulator is shown in the inverted
position for illustrative purposes.
INSPECTION
Inspect the accumulator piston and seal rings (Fig.
66). Replace the seal rings if worn or cut. Replace the
piston if chipped or cracked.
Check condition of the accumulator inner and
outer springs (Fig. 66). Replace the springs if the
coils are cracked, distorted or collapsed.
Fig. 62 Accumulator
1 - ACCUMULATOR PISTON
2 - PISTON SPRING
Fig. 63 3-4 Accumulator and Housing
1 - ACCUMULATOR PISTON
2 - 3-4 ACCUMULATOR HOUSING
3 - TEFLON SEALS
4 - PISTON SPRING
5 - COVER PLATE AND SCREWS
Fig. 64 Accumulator in DRIVE - FIRST Gear Position
1 - LINE PRESSURE
21 - 60 AUTOMATIC TRANSMISSION - 42REWJ

BANDS
DESCRIPTION
KICKDOWN (FRONT) BAND
The kickdown, or ªfrontº, band (Fig. 67) holds the
common sun gear of the planetary gear sets. The
front (kickdown) band is made of steel, and faced on
its inner circumference with a friction-type lining.
One end of the band is anchored to the transmissioncase, and the other is acted on with a pushing force
by a servo piston. The front band is a single-wrap
design (the band does not completely encompass/
wrap the drum that it holds).
LOW/REVERSE (REAR) BAND
The low/reverse band, or ªrearº, band (Fig. 68) is
similar in appearance and operation to the front
band. The rear band is slightly different in that it
does not use a link bar, but is acted directly on by
the apply lever. This is referred to as a double-wrap
band design (the drum is completely encompassed/
wrapped by the band). The double-wrap band pro-
vides a greater holding power in comparison to the
single-wrap design.
OPERATION
KICKDOWN (FRONT) BAND
The kickdown band holds the common sun gear of
the planetary gear sets by applying and holding the
front clutch retainer, which is splined to the sun gear
driving shell, and in turn splined directly to the sun
gear. The application of the band by the servo is typ-
ically done by an apply lever and link bar.
LOW/REVERSE (REAR) BAND
The rear band holds the rear planet carrier sta-
tionary by being mounted around and applied to the
low/reverse drum.
Fig. 65 Accumulator in SECOND Gear Position
1 - BOTTOM OF BORE
2 - LINE PRESSURE
3 - SHUTTLE VALVE
Fig. 66 Accumulator Components
1 - INNER SPRING
2 - ACCUMULATOR PISTON
3 - OUTER SPRING
4 - SEAL RINGS
Fig. 67 Front Band
1 - FRONT BAND
2 - TRANSMISSION HOUSING
WJAUTOMATIC TRANSMISSION - 42RE 21 - 61
BANDS (Continued)