Wire JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual

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
NO START IN PARK
OR NEUTRAL1. Gearshift Linkage/Cable
Mis-adjusted.1. Adjust linkage/cable.
2. Neutral Sense Wire Open/Cut. 2. Check continuity with test lamp. Repair as
required.
3. Park/Neutral Switch, or
Transmission Range Sensor Faulty.3. Refer to service section for test and
replacement procedure.
4. Park/Neutral Switch, or
Transmission Range Sensor
Connection Faulty.4. Connectors spread open. Repair.
5. Valve Body Manual Lever
Assembly Bent/Worn/Broken.5. Inspect lever assembly and replace if damaged.
NO REVERSE (OR
SLIPS IN REVERSE)1. Direct Clutch Pack (front clutch)
Worn.1. Disassemble unit and rebuild clutch pack.
2. Rear Band Mis-adjusted. 2. Adjust band.
3. Front Clutch Malfunctioned/
Burned.3. Air-pressure test clutch operation. Remove and
rebuild if necessary.
4. Overdrive Thrust Bearing
Failure.4. Disassemble geartrain and replace bearings.
5. Direct Clutch Spring Collapsed/
Broken.5. Remove and disassemble unit. Check clutch
position and replace spring.
WJAUTOMATIC TRANSMISSION - 42RE 21 - 25
AUTOMATIC TRANSMISSION - 42RE (Continued)

REMOVAL
The overdrive unit can be removed and serviced
separately. It is not necessary to remove the entire
transmission assembly to perform overdrive unit
repairs.
If only the overdrive unit requires service, refer to
Overdrive Removal for proper procedures.
CAUTION: The transmission and torque converter
must be removed as an assembly to avoid compo-
nent damage. The converter driveplate, pump bush-
ing, or oil seal can be damaged if the converter is
left attached to the driveplate during removal. Be
sure to remove the transmission and converter as
an assembly.
(1) Disconnect battery negative cable.
(2) Disconnect and lower or remove necessary
exhaust components.
(3) Disconnect fluid cooler lines at transmission.
(4) Remove starter motor. (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - REMOVAL)
(5) Disconnect and remove crankshaft position sen-
sor. (Refer to 14 - FUEL SYSTEM/FUEL INJEC-
TION/CRANKSHAFT POSITION SENSOR -
REMOVAL) Retain sensor attaching bolts.
CAUTION: The crankshaft position sensor will be
damaged if the transmission is removed, or
installed, while the sensor is still bolted to the
engine block, or transmission (4.0L only). To avoid
damage, be sure to remove the sensor before
removing the transmission.
(6) Remove the bolts holding the bell housing
brace to the transmission.
(7) Remove nut holding the bell housing brace to
the engine to transmission bending brace.
(8) Remove the bell housing brace from the trans-
mission (Fig. 13).
(9) Remove the bolt holding the torque converter
cover to the transmission.
(10) Remove the torque converter cover from the
transmission.
(11) If transmission is being removed for overhaul,
remove transmission oil pan, drain fluid and reinstall
pan.
(12) Remove fill tube bracket bolts and pull tube
out of transmission. Retain fill tube seal. On4x4
models, it will also be necessary to remove bolt
attaching transfer case vent tube to converter hous-
ing.
(13) Rotate crankshaft in clockwise direction until
converter bolts are accessible. Then remove bolts one
at a time. Rotate crankshaft with socket wrench on
dampener bolt.(14) Mark propeller shaft and axle yokes for
assembly alignment. Then disconnect and remove
propeller shaft. On4x4models, remove both propel-
ler shafts.
(15) Disconnect wires from park/neutral position
switch and transmission solenoid.
(16) Disconnect gearshift cable from transmission
manual valve lever (Fig. 14).
Fig. 13 Bell Housing Brace and Converter Cover
1 - Transmission
2 - Torque Converter Cover
3 - Bellhousing Brace
Fig. 14 Transmission Shift Cable
1 - SHIFT CABLE
2 - MANUAL LEVER
3 - MANUAL LEVER
WJAUTOMATIC TRANSMISSION - 42RE 21 - 27
AUTOMATIC TRANSMISSION - 42RE (Continued)

(11) Move transmission forward. Then raise, lower
or tilt transmission to align converter housing with
engine block dowels.
(12) Carefully work transmission forward and over
engine block dowels until converter hub is seated in
crankshaft.
(13) Install two bolts to attach converter housing
to engine.
(14) Install the upper transmission bending braces
to the torque converter housing and the overdrive
unit. Tighten the bolts to 41 N´m (30 ft.lbs.).
(15) Install remaining torque converter housing to
engine bolts. Tighten to 68 N´m (50 ft.lbs.).
(16) Install rear transmission crossmember.
Tighten crossmember to frame bolts to 68 N´m (50
ft.lbs.).
(17) Install rear support to transmission. Tighten
bolts to 47 N´m (35 ft.lbs.).
(18) Lower transmission onto crossmember and
install bolts attaching transmission mount to cross-
member. Tighten clevis bracket to crossmember bolts
to 47 N´m (35 ft.lbs.). Tighten the clevis bracket to
rear support bolt to 68 N´m (50 ft.lbs.).
(19) Remove engine support fixture.
(20) Install crankshaft position sensor. (Refer to 14
- FUEL SYSTEM/FUEL INJECTION/CRANKSHAFT
POSITION SENSOR - INSTALLATION)
(21) Install new plastic retainer grommet on any
shift cable that was disconnected. Grommets should
not be reused. Use pry tool to remove rod from grom-
met and cut away old grommet. Use pliers to snap
new grommet into cable and to snap grommet onto
lever.
(22) Connect gearshift and throttle valve cable to
transmission.
(23) Connect wires to park/neutral position switch
and transmission solenoid connector. Be sure trans-
mission harnesses are properly routed.CAUTION: It is essential that correct length bolts be
used to attach the converter to the driveplate. Bolts
that are too long will damage the clutch surface
inside the converter.
(24) Install all torque converter-to-driveplate bolts
by hand.
(25) Verify that the torque converter is pulled
flush to the driveplate. Tighten bolts to 31 N´m (270
in. lbs.).
(26) Install converter housing access cover. Tighten
bolt to 23 N´m (200 in.lbs.).
(27) Install the bell housing brace to the torque
converter cover and the engine to transmission bend-
ing brace. Tighten the bolts and nut to 41 N´m (30
ft.lbs.).
(28) Install starter motor (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - INSTALLA-
TION) and cooler line bracket.
(29) Connect cooler lines to transmission.
(30) Install transmission fill tube. Install new seal
on tube before installation.
(31) Install exhaust components.
(32) Install transfer case. Tighten transfer case
nuts to 35 N´m (26 ft.lbs.).
(33) Install the transfer case shift cable to the
cable support bracket and the transfer case shift
lever.
(34) Align and connect propeller shaft(s).
(35) Adjust gearshift linkage and throttle valve
cable if necessary.
(36) Lower vehicle.
(37) Fill transmission with MopartATF +4, type
9602, fluid.
21 - 42 AUTOMATIC TRANSMISSION - 42REWJ
AUTOMATIC TRANSMISSION - 42RE (Continued)

REMOVAL
(1) Hoist and support vehicle on safety stands.
(2) Remove transmission fluid pan and filter.
(3) Disengage wire connectors from pressure sen-
sor and solenoid (Fig. 75).
(4) Remove screws holding pressure solenoid
retainer to governor body.
(5) Separate solenoid retainer from governor (Fig.
76).
(6) Pull solenoid from governor body (Fig. 77).
(7) Pull pressure sensor from governor body.
(8) Remove bolts holding governor body to valve
body.(9) Separate governor body from valve body (Fig.
78).
(10) Remove governor body gasket.
INSTALLATION
Before installing the pressure sensor and solenoid
in the governor body, replace o-ring seals, clean the
gasket surfaces and replace gasket.
(1) Place gasket in position on back of governor
body (Fig. 79).
(2) Place governor body in position on valve body.
(3) Install bolts to hold governor body to valve
body.
(4) Lubricate o-ring on pressure sensor with trans-
mission fluid.
(5) Align pressure sensor to bore in governor body.
Fig. 75 Governor Solenoid And Pressure Sensor
1 - PRESSURE SENSOR
2 - PRESSURE SOLENOID
3 - GOVERNOR
Fig. 76 Pressure Solenoid Retainer
1 - PRESSURE SOLENOID RETAINER
2 - GOVERNOR
Fig. 77 Pressure Solenoid and O-ring
1 - PRESSURE SOLENOID
2 - O-RING
3 - GOVERNOR
Fig. 78 Governor Body and Gasket
1 - GOVERNOR BODY
2 - GASKET
WJAUTOMATIC TRANSMISSION - 42RE 21 - 67
ELECTRONIC GOVERNOR (Continued)

(6) Push pressure sensor into governor body.
(7) Lubricate o-ring, on pressure solenoid, with
transmission fluid.
(8) Align pressure solenoid to bore in governor
body (Fig. 80).
(9) Push solenoid into governor body.
(10) Place solenoid retainer in position on governor
(Fig. 81).
(11) Install screws to hold pressure solenoid
retainer to governor body.
(12) Engage wire connectors into pressure sensor
and solenoid (Fig. 82).
(13) Install transmission fluid pan and (new) filter.
(14) Lower vehicle and road test to verify repair.
EXTENSION HOUSING
BUSHING
REMOVAL
(1) Remove extension housing yoke seal.
(2) Insert Remover 6957 into the extension hous-
ing. Tighten tool to bushing and remove bushing
(Fig. 83).
INSTALLATION
(1) Align bushing oil hole with oil slot in extension
housing.
(2) Tap bushing into place with Installer 6951 and
Handle C-4171.
Fig. 79 Governor Body and Gasket
1 - GOVERNOR BODY
2 - GASKET
Fig. 80 Pressure Solenoid and O-ring
1 - PRESSURE SOLENOID
2 - O-RING
3 - GOVERNOR
Fig. 81 Pressure Solenoid Retainer
1 - PRESSURE SOLENOID RETAINER
2 - GOVERNOR
Fig. 82 Governor Solenoid And Pressure Sensor
1 - PRESSURE SENSOR
2 - PRESSURE SOLENOID
3 - GOVERNOR
21 - 68 AUTOMATIC TRANSMISSION - 42REWJ
ELECTRONIC GOVERNOR (Continued)

OVERDRIVE CLUTCH PACK
(1) Remove overdrive clutch pack wire retaining
ring (Fig. 132).
(2) Remove overdrive clutch pack (Fig. 133).
NOTE: The 42RE transmission has three clutch
discs and two clutch plates.
(3) Note position of clutch pack components for
assembly reference (Fig. 134).
Fig. 131 Overdrive Piston Removal
1 - PISTON RETAINER
2 - OVERDRIVE PISTON
Fig. 132 Removing Overdrive Clutch Pack Retaining
Ring
1 - OVERDRIVE CLUTCH PACK RETAINING RING
Fig. 133 Overdrive Clutch Pack Removal
1 - OVERDRIVE CLUTCH PACK
Fig. 134 42RE Overdrive Clutch Component
Position
1 - PRESSURE PLATE (TO FRONT)
2 - OVERDRIVE CLUTCH PACK
3 - CLUTCH DISC (3)
4 - CLUTCH PLATE (2)
5 - REACTION PLATE (TO REAR)
WJAUTOMATIC TRANSMISSION - 42RE 21 - 89
OVERDRIVE UNIT (Continued)

NOTE: The reaction plate is thinner than the pres-
sure plate in a 42RE transmission.
(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. 182).
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. 183). 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. 183).
(d) Select proper thickness end play spacer from
spacer chart based on distance measured (Fig.
184).
(e) Remove Gauge Alignment Tool 6312.
Fig. 177 Seating Locating Ring In Rear Bearing
1 - EXPAND BEARING LOCATING RING WITH SNAP-RING
PLIERS
2 - ACCESS HOLE
Fig. 178 Locating Ring Access Cover And Gasket
Installation
1 - TORX SCREWDRIVER (T25)
2 - ACCESS COVER SCREWS
Fig. 179 Overdrive Clutch Reaction Ring Installation
1 - REACTION RING
2 - CLUTCH HUB
Fig. 180 Overdrive Clutch Wave Spring Installation
1 - WAVE SPRING
21 - 102 AUTOMATIC TRANSMISSION - 42REWJ
OVERDRIVE UNIT (Continued)

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.
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. 198).
Fig. 197 Brake Transmission Shift Interlock
1 - SHIFT MECHANISM 4 - STEERING COLUMN ASSEMBLY
2 - SHIFTER BTSI LEVER 5 - INTERLOCK CABLE
3 - ADJUSTMENT CLIP
WJAUTOMATIC TRANSMISSION - 42RE 21 - 109
PARK LOCK CABLE (Continued)

(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. 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 converts 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. 199) 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: 100lbs. 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. 200)
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.
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.
Fig. 198 Park/Neutral Position Switch
1 - NEUTRAL CONTACT
2 - MANUAL LEVER AND SWITCH PLUNGER IN REVERSE
POSITION
3 - PARK CONTACT
4 - SWITCH
Fig. 199 Force and Pressure Relationship
21 - 110 AUTOMATIC TRANSMISSION - 42REWJ
PARK/NEUTRAL POSITION SWITCH (Continued)