fluid JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual

HOSES - 4.7L
DESCRIPTION
DESCRIPTION - 1/2º PRESSURE HOSE
The hose consists of two metal ends and a rubber
center with quick connect nuts at both ends. The
hose connects the power steering pump to the
hydraulic fan motor and is clipped to the fan shroud
(Fig. 8). Lubrication must be used on the quick con-
nect nuts and o-rings when installing.
DESCRIPTION - 1/2º RETURN HOSE
The fan motor return line is a molded rubber hose
that is clamped at the hydraulic motor and the power
steering reservoir (Fig. 9).
DESCRIPTION - 3/8º PRESSURE HOSE
The hose consists of two metal ends and two rub-
ber sections one of which contains a tuning cable
(Fig. 10). The hose is clipped in two places to the fan
shroud. Lubrication must be used on the o-rings
when installing.
DESCRIPTION - 3/8º GEAR OUTLET HOSE
The gear outlet line consists of a metal section that
connects to the gear and a rubber section that clamps
to the steering cooler inlet tube (Fig. 11).
DESCRIPTION - 3/8º RETURN HOSE
The return hose is a formed rubber hose that con-
nects the steering cooler outlet tube to the power
steering reservoir (Fig. 12). It is clamped at both
ends.
OPERATION
OPERATION - 1/2º PRESSURE HOSE
The 1/2º pressure hose is used to transfer high
pressure power steering fluid from the power steer-
ing pump to the engine cooling fan motor (Fig. 8).
OPERATION - 1/2º RETURN HOSE
The power steering return line returns low pres-
sure excess flow from the hydraulic fan motor back to
the power steering pump (Fig. 9).
Fig. 8 1/2(PRESSURE HOSE
1 - 1/29PRESSURE HOSE
2 - POWER STEERING PUMP
3 - STEERING GEAR
Fig. 9 1/2(RETURN HOSE
1 - 1/29RETURN HOSE
2 - HOSE CLAMP
Fig. 10 3/8(PRESSURE HOSE
1 - 3/89PRESSURE HOSE
2 - STEERING GEAR
19 - 38 PUMPWJ

OPERATION - 3/8º PRESSURE HOSE
High pressure power steering fluid is transmitted
from the hydraulic fan motor to the steering gear by
the 3/8º steering line.
OPERATION - 3/8º GEAR OUTLET HOSE
The gear outlet hose transmits power steering fluid
under moderate low pressure to the power steering
cooler inlet tube.
OPERATION - 3/8ºRETURN HOSE
Low pressure power steering fluid is transmitted
from the steering cooler back to the power steering
pump by the 3/8º return hose.
REMOVAL
REMOVAL - 1/2(PRESSURE HOSE
(1)Drain the power steering fluid from the reservoir.
(2) Remove the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(3) Raise and support the vehicle.
(4) Remove the metal skid plate.
(5) Disconnect the high pressure hose from the
hydraulic fan motor (Fig. 8).
(6) Disconnect the high pressure hose from the
power steering pump (Fig. 8).
(7) Remove the hose from the clipped position on
the fan shroud.
(8) Remove the hose from the vehicle.
REMOVAL - 1/2(RETURN HOSE
(1) Drain the power steering fluid from the reser-
voir.
(2) Remove the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(3) Raise and support the vehicle.
(4) Remove the metal skid plate.
(5) Disconnect the rubber return hose from the
hydraulic fan motor (Fig. 9).
(6) Disconnect the rubber return hose from the
power steering reservoir .
(7) Remove the hose from the vehicle.
REMOVAL - 3/8(PRESSURE HOSE
(1) Drain the power steering fluid from the reser-
voir.
(2) Remove the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(3) Raise and support the vehicle.
(4) Remove the metal skid plate.
(5) Disconnect the high pressure hose from the
hydraulic fan motor (Fig. 10).
(6) Disconnect the high pressure hose from the
power steering gear (Fig. 10).
(7) Remove the hose from the clipped position on
the fan shroud.
(8) Remove the hose from the vehicle.
REMOVAL - 3/8(RETURN HOSE
(1) Drain the power steering fluid from the reser-
voir.
(2) Remove the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(3) Raise and support the vehicle.
(4) Disconnect the rubber hose from the steering
cooler outlet tube (Fig. 12).
Fig. 11 3/8(GEAR OUTLET HOSE
1 - HOSE CLAMP
2 - 3/89GEARR OUTLET HOSE
Fig. 12 3/8(RETURN HOSE
1 - HOSE CLAMP
2 - 3/89RETURN HOSE
3 - HYDRAULIC COOLING FAN MOTOR
WJPUMP 19 - 39
HOSES - 4.7L (Continued)

(5) Disconnect the rubber hose from the power
steering reservoir (Fig. 12).
(6) Remove the hose from the vehicle.
REMOVAL - 3/8(GEAR OUTLET HOSE
(1) Drain the power steering fluid from the reser-
voir.
(2) Remove the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(3) Raise and support the vehicle.
(4) Disconnect the rubber hose from the steering
cooler inlet tube (Fig. 11).
(5) Disconnect the metal tube from the power
steering gear (Fig. 11).
(6) Remove the hose from the vehicle.
REMOVAL - INLET COOLER HOSE
(1) Disconnect negative battery cable at battery.
(2) Drain the power steering fluid out of the reser-
voir.
(3) Remove the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(4) Remove the front fascia grille assembly,(Refer
to 13 - FRAMES & BUMPERS/BUMPERS/FRONT
FASCIA - REMOVAL).
(5) Remove the grille opening reinforcement panel
(6) Place a drain pan under the cooler.
(7) Disconnect the lower hose at cooler (Fig. 6).
(8) Disconnect the cooler hose at the gear.
(9) Remove the bracket holding the cooler hoses
(Fig. 13).
(10) Remove the cooler hose from the vehicle.
REMOVAL - OUTLET COOLER HOSE
(1) Disconnect negative battery cable at battery.
(2) Drain the power steering fluid out of the reser-
voir.
(3) Remove the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
(4) Remove the front fascia grille assembly,(Refer
to 13 - FRAMES & BUMPERS/BUMPERS/FRONT
FASCIA - REMOVAL).
(5) Remove the grille opening reinforcement panel
(6) Place a drain pan under the cooler.
(7) Disconnect the upper hose at cooler (Fig. 6).
(8) Disconnect the cooler hose at the reservoir.
(9) Remove the bracket holding the cooler hoses
(Fig. 13).
(10) Remove the cooler hose from the vehicle.
INSTALLATION
INSTALLATION - 1/2(PRESSURE HOSE
NOTE: Lubrication and a new o-ring must be used
when reinstalling.
(1) Install the hoses to the vehicle.
(2) Reconnect the high pressure hose to the power
steering pump (Fig. 8) Tighten the hose to 22.5 N´m
(17 ft.lbs.).
(3) Reconnect the high pressure hose to the
hydraulic fan motor (Fig. 8) Tighten the hose to 22.5
N´m (17 ft.lbs.).
(4) Install the hose to the clipped position on the
fan shroud.
(5) Install the metal skid plate.
(6) Install the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
INSTALLATION).
(7) Refill the power steering fluid and bleed the
system,(Refer to 19 - STEERING/PUMP - STAN-
DARD PROCEDURE).
INSTALLATION - 1/2(RETURN HOSE
(1) Install the hoses to the vehicle.
(2) Reconnect the rubber return hose to the power
steering reservoir (Fig. 9) Tighten the hose clamp.
(3) Reconnect the rubber return hose to the
hydraulic fan motor (Fig. 9) Tighten the hose.
(4) Install the metal skid plate.
(5) Install the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
INSTALLATION).
(6) Refill the power steering fluid and bleed the
system,(Refer to 19 - STEERING/PUMP - STAN-
DARD PROCEDURE).
Fig. 13 COOLER HOSES MOUNTING BRACKET
1 - RADIATOR
2 - COOLER HOSES MOUNTING BRACKET
2 - COOLER HOSE
19 - 40 PUMPWJ
HOSES - 4.7L (Continued)

INSTALLATION - 3/8(PRESSURE HOSE
NOTE: Lubrication and a new o-ring must be used
when reinstalling.
(1) Install the hoses to the vehicle.
(2) Reconnect the high pressure hose to the
hydraulic fan motor (Fig. 10) Tighten the hose to
22.5 N´m (17 ft.lbs.).
(3) Reconnect the high pressure hose to the power
steering gear (Fig. 10) Tighten the hose to 22.5 N´m
(17 ft.lbs.).
(4) Install the hose to the clipped position on the
fan shroud.
(5) Install the metal skid plate.
(6) Install the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
INSTALLATION).
(7) Refill the power steering fluid and bleed the
system,(Refer to 19 - STEERING/PUMP - STAN-
DARD PROCEDURE).
INSTALLATION - 3/8(RETURN HOSE
(1) Install the hoses to the vehicle.
(2) Reconnect the rubber hose to the steering
cooler outlet tube (Fig. 12) Tighten the hose clamp.
(3) Reconnect the rubber hose to the power steer-
ing reservoir (Fig. 12) Tighten the hose clamp.
(4) Install the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
INSTALLATION).
(5) Refill the power steering fluid and bleed the
system,(Refer to 19 - STEERING/PUMP - STAN-
DARD PROCEDURE).
INSTALLATION - 3/8(GEAR OUTLET HOSE
NOTE: Lubrication and a new o-ring must be used
when reinstalling.
(1) Install the hoses to the vehicle.
(2) Reconnect the rubber hose to the steering
cooler inlet tube (Fig. 11) Tighten the hose clamp.
(3)
Reconnect the metal tube to the power steering
gear (Fig. 11) Tighten the hose to 22.5 N´m (17 ft.lbs.).
(4) Install the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
INSTALLATION).
(5) Refill the power steering fluid and bleed the
system,(Refer to 19 - STEERING/PUMP - STAN-
DARD PROCEDURE).
INSTALLATION - INLET COOLER HOSE
(1) Install the cooler hose to the vehicle.
(2) Reconnect the cooler hose at the gear.
(3) Reconnect the lower hose at cooler (Fig. 6).
Tighten the hose to 22.5 N´m (17 ft.lbs.)
(4) Install the bracket holding the cooler hoses
(Fig. 13).(5) Install the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
INSTALLATION).
(6) Install the grille opening reinforcement panel
(7) Install the front fascia grille assembly, (Refer to
13 - FRAMES & BUMPERS/BUMPERS/FRONT
FASCIA - INSTALLATION).
(8) Reconnect negative battery cable at battery.
(9) Refill the power steering fluid and bleed the
system,(Refer to 19 - STEERING/PUMP - STAN-
DARD PROCEDURE).
INSTALLATION - OUTLET COOLER HOSE
(1) Install the cooler hose to the vehicle.
(2) Reconnect the cooler hose at the reservoir.
(3) Reconnect the upper hose at the cooler (Fig. 6).
Tighten the hose to 22.5 N´m (17 ft. lbs.)
(4) Install the bracket holding the cooler hoses
(Fig. 13). Tighten the bracket to 22.5 N´m (17 ft. lbs.)
(5) Install the air box,(Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
INSTALLATION).
(6) Install the grille opening reinforcement panel
(7) Install the front fascia grille assembly, (Refer to
13 - FRAMES & BUMPERS/BUMPERS/FRONT
FASCIA - INSTALLATION).
(8) Reconnect negative battery cable at battery.
(9) Refill the power steering fluid and bleed the
system,(Refer to 19 - STEERING/PUMP - STAN-
DARD PROCEDURE).
PULLEY
DESCRIPTION
POWER STEERING PUMP PULLEY - 3.1L
DIESEL
To service the power steering pump pulley on the
3.1L turbo diesel engine. Refer to the power steering
pump removal and installation procedure in this
group. The pulley must be removed to service the
pump assembly. Detailed instructions are provided in
the pump procedure.
REMOVAL
CAUTION: On vehicles equipped with the 4.0L or
4.7L, Do not reuse the old power steering pump
pulley it is not intended for reuse. A new pulley
must be installed if removed.
(1) Remove pump assembly.
(2) Remove pulley from pump with Puller C-4333
or equivalent puller (Fig. 14).
WJPUMP 19 - 41
HOSES - 4.7L (Continued)

INSTALLATION
NOTE: The pulley is marked front for installation.
CAUTION: On vehicles equipped with the 4.0L or
4.7L, Do not reuse the old power steering pump
pulley it is not intended for reuse. A new pulley
must be installed if removed.
(1) Replace pulley if bent, cracked, or loose.
(2) Install pulley on pump with Installer C-4063-B
or equivalent installer (Fig. 15). The front edge of the
pulley hub must be flush with the end of the shaft.
Ensure the tool and pulley are aligned with the
pump shaft.(3) Install pump assembly.
(4) With Serpentine Belt, run engine until warm (5
min.) and note any belt chirp. If chirp exists, move
pulley outward approximately 0.5 mm (0.020 in.). If
noise increases, press on 1.0 mm (0.040 in.).Be
careful that pulley does not contact mounting
bolts.
RESERVOIR
REMOVAL
(1) Remove power steering pump.
(2) Clean exterior of pump.
(3) Clamp the pump body in a soft jaw vice.
NOTE: Use new retaining clips for installation.
(4) Pry up tab and slide the retaining clips off (Fig.
16).
(5) Remove fluid reservoir from pump body.
Remove and discard O-ring seal.
INSTALLATION
(1) Lubricate new O-ring Seal with Mopar Power
Steering Fluid or equivalent.
(2) Install O-ring seal in housing.
(3) Install reservoir onto housing.
(4) Slide and tap innewreservoir retainer clips
until tab locks to housing.
(5) Install power steering pump.
(6) Add power steering fluid,(Refer to 19 - STEER-
ING/PUMP - STANDARD PROCEDURE).
Fig. 14 Pulley Removal
1 - POWER STEERING PUMP DRIVE PULLEY
2 - SPECIAL TOOL C-4333
Fig. 15 Pulley Installation
1 - POWER STEERING PUMP DRIVE PULLEY
2 - SPECIAL TOOL C-4063±B
Fig. 16 Pump Reservoir Clips
1 - RESERVOIR
2 - RETAINING CLIPS
19 - 42 PUMPWJ
PULLEY (Continued)

TRANSMISSION AND TRANSFER CASE
TABLE OF CONTENTS
page page
AUTOMATIC TRANSMISSION - 42RE..........1
AUTOMATIC TRANSMISSION - 545RFE......177TRANSFER CASE - NV242................280
TRANSFER CASE - NV247................315
AUTOMATIC TRANSMISSION - 42RE
TABLE OF CONTENTS
page page
AUTOMATIC TRANSMISSION - 42RE
DESCRIPTION..........................3
OPERATION............................5
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION......................11
DIAGNOSIS AND TESTING - PRELIMINARY . 11
DIAGNOSIS AND TESTING - ROAD
TESTING............................11
DIAGNOSIS AND TESTING - HYDRAULIC
PRESSURE TEST.....................12
DIAGNOSIS AND TESTING - AIR CHECKING
TRANSMISSION CLUTCH AND BAND
OPERATION.........................15
DIAGNOSIS AND TESTING - CONVERTER
HOUSING FLUID LEAK.................15
DIAGNOSIS AND TESTING - DIAGNOSIS
CHARTS............................16
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR......................26
REMOVAL.............................27
DISASSEMBLY.........................29
CLEANING............................34
INSPECTION..........................34
ASSEMBLY............................34
INSTALLATION.........................41
SCHEMATICS AND DIAGRAMS
HYDRAULIC SCHEMATICS..............43
SPECIFICATIONS
TRANSMISSION......................55
SPECIAL TOOLS
RE TRANSMISSIONS..................57
ACCUMULATOR
DESCRIPTION.........................60
OPERATION...........................60
INSPECTION..........................60BANDS
DESCRIPTION.........................61
OPERATION...........................61
ADJUSTMENTS
ADJUSTMENT - BANDS................62
BRAKE TRANSMISSION SHIFT INTERLOCK
MECHANISM
DESCRIPTION.........................63
OPERATION...........................63
DIAGNOSIS AND TESTING - BRAKE
TRANSMISSION SHIFT INTERLOCK.......63
ADJUSTMENTS - BRAKE TRANSMISSION
SHIFT INTERLOCK....................64
ELECTRONIC GOVERNOR
DESCRIPTION.........................65
OPERATION...........................65
REMOVAL.............................67
INSTALLATION.........................67
EXTENSION HOUSING BUSHING
REMOVAL.............................68
INSTALLATION.........................68
EXTENSION HOUSING SEAL
REMOVAL.............................69
INSTALLATION.........................69
FLUID AND FILTER
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL..............69
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID........................69
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION.....................70
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK.............................70
WJTRANSMISSION AND TRANSFER CASE 21 - 1

STANDARD PROCEDURE - FLUID AND
FILTER REPLACEMENT................71
STANDARD PROCEDURE - TRANSMISSION
FILL................................72
FRONT CLUTCH
DESCRIPTION.........................73
OPERATION...........................74
DISASSEMBLY.........................74
INSPECTION..........................74
ASSEMBLY............................74
FRONT SERVO
DESCRIPTION.........................77
OPERATION...........................77
DISASSEMBLY.........................77
CLEANING............................77
INSPECTION..........................77
ASSEMBLY............................77
GEARSHIFT CABLE
DIAGNOSIS AND TESTING - GEARSHIFT
CABLE..............................78
REMOVAL.............................78
INSTALLATION.........................79
ADJUSTMENTS - GEARSHIFT CABLE.......79
OIL PUMP
DESCRIPTION.........................80
OPERATION...........................80
STANDARD PROCEDURE - OIL PUMP
VOLUME CHECK......................81
DISASSEMBLY.........................81
CLEANING............................83
INSPECTION..........................83
ASSEMBLY............................83
OUTPUT SHAFT FRONT BEARING
REMOVAL.............................85
INSTALLATION.........................85
OUTPUT SHAFT REAR BEARING
REMOVAL.............................85
INSTALLATION.........................85
OVERDRIVE CLUTCH
DESCRIPTION.........................86
OPERATION...........................86
OVERDRIVE OFF SWITCH
DESCRIPTION.........................86
OPERATION...........................86
DIAGNOSIS AND TESTING - OVERDRIVE
ELECTRICAL CONTROLS...............87
OVERDRIVE UNIT
REMOVAL.............................87
DISASSEMBLY.........................88
CLEANING............................95
INSPECTION..........................95
ASSEMBLY............................95
INSTALLATION........................104
OVERRUNNING CLUTCH CAM/OVERDRIVE
PISTON RETAINER
DESCRIPTION........................105
OPERATION..........................105DISASSEMBLY........................106
CLEANING...........................106
INSPECTION.........................106
ASSEMBLY...........................106
PARK LOCK CABLE
REMOVAL............................108
INSTALLATION........................108
PARK/NEUTRAL POSITION SWITCH
DIAGNOSIS AND TESTING - PARK/NEUTRAL
POSITION SWITCH...................109
REMOVAL............................109
INSTALLATION........................109
PISTONS
DESCRIPTION........................110
OPERATION..........................110
PLANETARY GEARTRAIN/OUTPUT SHAFT
DESCRIPTION........................112
OPERATION..........................112
DISASSEMBLY........................112
INSPECTION..........................113
ASSEMBLY...........................113
REAR CLUTCH
DESCRIPTION........................118
OPERATION..........................118
DISASSEMBLY........................119
CLEANING...........................119
INSPECTION.........................120
ASSEMBLY...........................120
REAR SERVO
DESCRIPTION........................122
OPERATION..........................122
DISASSEMBLY........................122
CLEANING...........................122
ASSEMBLY...........................123
SHIFT MECHANISM
DESCRIPTION........................123
OPERATION..........................123
REMOVAL............................123
INSTALLATION........................125
SOLENOID
DESCRIPTION........................125
OPERATION..........................126
SPEED SENSOR
DESCRIPTION........................126
OPERATION..........................126
THROTTLE VALVE CABLE
DESCRIPTION........................126
ADJUSTMENTS - TRANSMISSION THROTTLE
VALVE CABLE.......................126
TORQUE CONVERTER
DESCRIPTION........................128
OPERATION..........................132
REMOVAL............................133
INSTALLATION........................133
TORQUE CONVERTER DRAINBACK VALVE
DESCRIPTION........................134
OPERATION..........................134
21 - 2 AUTOMATIC TRANSMISSION - 42REWJ

STANDARD PROCEDURE - TORQUE
CONVERTER DRAINBACK VALVE........134
TRANSMISSION TEMPERATURE SENSOR
DESCRIPTION........................134
OPERATION..........................134
VALVE BODY
DESCRIPTION........................135
OPERATION..........................139REMOVAL............................154
DISASSEMBLY........................155
CLEANING...........................165
INSPECTION.........................166
ASSEMBLY...........................167
INSTALLATION........................175
ADJUSTMENTS - VALVE BODY...........175
AUTOMATIC TRANSMISSION -
42RE
DESCRIPTION
The 42RE is a four speed fully automatic transmis-
sion (Fig. 1) with an electronic governor. The 42RE is
equipped with a lock-up clutch in the torque con-
verter. First through third gear ranges are provided
by the clutches, bands, overrunning clutch, and plan-
etary gear sets in the transmission. Fourth gear
range is provided by the overdrive unit that contains
an overdrive clutch, direct clutch, planetary gear set,
and overrunning clutch.The transmission contains a front, rear, and direct
clutch which function as the input driving compo-
nents. It also contains the kickdown (front) and the
low/reverse (rear) bands which, along with the over-
running clutch and overdrive clutch, serve as the
holding components. The driving and holding compo-
nents combine to select the necessary planetary gear
components, in the front, rear, or overdrive planetary
gear set, transfer the engine power from the input
shaft through to the output shaft.
The valve body is mounted to the lower side of the
transmission and contains the valves to control pres-
sure regulation, fluid flow control, and clutch/band
application. The oil pump is mounted at the front of
the transmission and is driven by the torque con-
verter hub. The pump supplies the oil pressure nec-
essary for clutch/band actuation and transmission
lubrication.
WJAUTOMATIC TRANSMISSION - 42RE 21 - 3

IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan gas-
ket surface (Fig. 2). Refer to this information when
ordering replacement parts.
GEAR RATIOS The 42RE gear ratios are:
1st.................................2.74:1
2nd................................1.54:1
3rd.................................1.00:1
4th.................................0.69:1
Rev.................................2.21:1
OPERATION
The application of each driving or holding compo-
nent is controlled by the valve body based upon the
manual lever position, throttle pressure, and gover-
nor pressure. The governor pressure is a variable
pressure input to the valve body and is one of the
signals that a shift is necessary. First through fourth
gear are obtained by selectively applying and releas-
ing the different clutches and bands. Engine power is
thereby routed to the various planetary gear assem-
blies which combine with the overrunning clutch
assemblies to generate the different gear ratios. The
torque converter clutch is hydraulically applied and
is released when fluid is vented from the hydraulic
circuit by the torque converter control (TCC) solenoid
on the valve body. The torque converter clutch is con-
trolled by the Powertrain Control Module (PCM). The
torque converter clutch engages in fourth gear, and
in third gear under various conditions, such as when
the O/D switch is OFF, when the vehicle is cruising
on a level surface after the vehicle has warmed up.
The torque converter clutch will disengage momen-
tarily when an increase in engine load is sensed by
the PCM, such as when the vehicle begins to go
uphill or the throttle pressure is increased. The
torque converter clutch feature increases fuel econ-
omy and reduces the transmission fluid temperature.
Since the overdrive clutch is applied in fourth gear
only and the direct clutch is applied in all ranges
except fourth gear, the transmission operation for
park, neutral, and first through third gear will be
described first. Once these powerflows are described,
the third to fourth shift sequence will be described.
1 - CONVERTER CLUTCH 15 - HOUSING
2 - TORQUE CONVERTER 16 - REAR BEARING
3 - OIL PUMP AND REACTION SHAFT SUPPORT ASSEMBLY 17 - OUTPUT SHAFT
4 - FRONT BAND 18 - SEAL
5 - FRONT CLUTCH 19 - OVERDRIVE OVERRUNNING CLUTCH
6 - DRIVING SHELL 20 - OVERDRIVE PLANETARY GEAR
7 - REAR BAND 21 - DIRECT CLUTCH SPRING
8 - TRANSMISSION OVERRUNNING CLUTCH 22 - OVERDRIVE CLUTCH PISTON
9 - OVERDRIVE UNIT 23 - VALVE BODY ASSEMBLY
10 - PISTON RETAINER 24 - FILTER
11 - OVERDRIVE CLUTCH 25 - FRONT PLANETARY GEAR
12 - DIRECT CLUTCH 26 - REAR CLUTCH
13 - INTERMEDIATE SHAFT 27 - TRANSMISSION
14 - FRONT BEARING 28 - REAR PLANETARY GEAR
Fig. 2 Transmission Part And Serial Number
Location
1 - PART NUMBER
2 - BUILD DATE
3 - SERIAL NUMBER
WJAUTOMATIC TRANSMISSION - 42RE 21 - 5
AUTOMATIC TRANSMISSION - 42RE (Continued)

FOURTH GEAR POWERFLOW
Fourth gear overdrive range is electronically con-
trolled and hydraulically activated. Various sensor
inputs are supplied to the powertrain control module
to operate the overdrive solenoid on the valve body.
The solenoid contains a check ball that opens and
closes a vent port in the 3-4 shift valve feed passage.
The overdrive solenoid (and check ball) are not ener-
gized in first, second, third, or reverse gear. The vent
port remains open, diverting line pressure from the
2-3 shift valve away from the 3-4 shift valve. The
overdrive control switch must be in the ON position
to transmit overdrive status to the PCM. A 3-4
upshift occurs only when the overdrive solenoid is
energized by the PCM. The PCM energizes the over-
drive solenoid during the 3-4 upshift. This causes the
solenoid check ball to close the vent port allowing
line pressure from the 2-3 shift valve to act directly
on the 3-4 upshift valve. Line pressure on the 3-4
shift valve overcomes valve spring pressure moving
the valve to the upshift position. This action exposes
the feed passages to the 3-4 timing valve, 3-4 quick
fill valve, 3-4 accumulator, and ultimately to the
overdrive piston. Line pressure through the timing
valve moves the overdrive piston into contact with
the overdrive clutch. The direct clutch is disengaged
before the overdrive clutch is engaged. The boost
valve provides increased fluid apply pressure to the
overdrive clutch during 3-4 upshifts, and when accel-
erating in fourth gear. The 3-4 accumulator cushions
overdrive clutch engagement to smooth 3-4 upshifts.
The accumulator is charged at the same time as
apply pressure acts against the overdrive piston.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION
Automatic transmission problems can be a result of
poor engine performance, incorrect fluid level, incor-
rect linkage or cable adjustment, band or hydraulic
control pressure adjustments, hydraulic system mal-
functions or electrical/mechanical component mal-
functions. Begin diagnosis by checking the easily
accessible items such as: fluid level and condition,
linkage adjustments and electrical connections. A
road test will determine if further diagnosis is neces-
sary.
DIAGNOSIS AND TESTING - PRELIMINARY
Two basic procedures are required. One procedure
for vehicles that are drivable and an alternate proce-
dure for disabled vehicles (will not back up or move
forward).
VEHICLE IS DRIVEABLE
(1) Check for transmission fault codes using DRBt
scan tool.
(2) Check fluid level and condition.
(3) Adjust throttle and gearshift linkage if com-
plaint was based on delayed, erratic, or harsh shifts.
(4) Road test and note how transmission upshifts,
downshifts, and engages.
(5) Perform hydraulic pressure test if shift prob-
lems were noted during road test.
(6) Perform air-pressure test to check clutch-band
operation.
VEHICLE IS DISABLED
(1) Check fluid level and condition.
(2) Check for broken or disconnected gearshift or
throttle linkage.
(3) Check for cracked, leaking cooler lines, or loose
or missing pressure-port plugs.
(4) Raise and support vehicle on safety stands,
start engine, shift transmission into gear, and note
following:
(a) If propeller shaft turns but wheels do not,
problem is with differential or axle shafts.
(b) If propeller shaft does not turn and transmis-
sion is noisy, stop engine. Remove oil pan, and
check for debris. If pan is clear, remove transmis-
sion and check for damaged drive plate, converter,
oil pump, or input shaft.
(c) If propeller shaft does not turn and transmis-
sion is not noisy, perform hydraulic-pressure test to
determine if problem is hydraulic or mechanical.
DIAGNOSIS AND TESTING - ROAD TESTING
Before road testing, be sure the fluid level and con-
trol cable adjustments have been checked and
adjusted if necessary. Verify that diagnostic trouble
codes have been resolved.
Observe engine performance during the road test.
A poorly tuned engine will not allow accurate analy-
sis of transmission operation.
Operate the transmission in all gear ranges. Check
for shift variations and engine flare which indicates
slippage. Note if shifts are harsh, spongy, delayed,
early, or if part throttle downshifts are sensitive.
Slippage indicated by engine flare, usually means
clutch, band or overrunning clutch problems. If the
condition is advanced, an overhaul will be necessary
to restore normal operation.
A slipping clutch or band can often be determined
by comparing which internal units are applied in the
various gear ranges. The Clutch and Band Applica-
tion chart provides a basis for analyzing road test
results.
WJAUTOMATIC TRANSMISSION - 42RE 21 - 11
AUTOMATIC TRANSMISSION - 42RE (Continued)