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

OPERATION
The converter impeller (Fig. 115) (driving member),
which is integral to the converter housing and bolted
to the engine drive plate, rotates at engine speed.
The converter turbine (driven member), which reacts
from fluid pressure generated by the impeller, rotates
and turns the transmission input shaft.
TURBINE
As the fluid that was put into motion by the impel-
ler blades strikes the blades of the turbine, some of
the energy and rotational force is transferred into the
turbine and the input shaft. This causes both of them
(turbine and input shaft) to rotate in a clockwise
direction following the impeller. As the fluid is leav-
ing the trailing edges of the turbine's blades it con-
tinues in a ªhinderingº direction back toward the
impeller. If the fluid is not redirected before it strikes
the impeller, it will strike the impeller in such a
direction that it would tend to slow it down.
STATOR
Torque multiplication is achieved by locking the
stator's over-running clutch to its shaft (Fig. 116).
Under stall conditions (the turbine is stationary), the
oil leaving the turbine blades strikes the face of the
stator blades and tries to rotate them in a counter-
clockwise direction. When this happens the over-run-ning clutch of the stator locks and holds the stator
from rotating. With the stator locked, the oil strikes
the stator blades and is redirected into a ªhelpingº
direction before it enters the impeller. This circula-
tion of oil from impeller to turbine, turbine to stator,
and stator to impeller, can produce a maximum
torque multiplication of about 2.4:1. As the turbine
begins to match the speed of the impeller, the fluid
that was hitting the stator in such as way as to
cause it to lock-up is no longer doing so. In this con-
dition of operation, the stator begins to free wheel
and the converter acts as a fluid coupling.
TORQUE CONVERTER CLUTCH (TCC)
In a standard torque converter, the impeller and
turbine are rotating at about the same speed and the
stator is freewheeling, providing no torque multipli-
cation. By applying the turbine's piston and friction
material to the front cover, a total converter engage-
ment can be obtained. The result of this engagement
is a direct 1:1 mechanical link between the engine
and the transmission.
The clutch can be engaged in second, third, fourth,
and fifth gear ranges depending on overdrive control
switch position. If the overdrive control switch is in
the normal ON position, the clutch will engage after
the shift to fourth gear, and above approximately 72
km/h (45 mph). If the control switch is in the OFF
Fig. 115 Torque Converter Fluid Operation - Typical
1 - APPLY PRESSURE 3 - RELEASE PRESSURE
2 - THE PISTON MOVES SLIGHTLY FORWARD 4 - THE PISTON MOVES SLIGHTLY REARWARD
21 - 268 AUTOMATIC TRANSMISSION - 545RFEWJ
TORQUE CONVERTER (Continued)

position, the clutch will engage after the shift to
third gear, at approximately 56 km/h (35 mph) at
light throttle.
The TCM controls the torque converter by way of
internal logic software. The programming of the soft-
ware provides the TCM with control over the L/R-CC
Solenoid. There are four output logic states that can
be applied as follows:
²No EMCC
²Partial EMCC
²Full EMCC
²Gradual-to-no EMCC
NO EMCC
Under No EMCC conditions, the L/R Solenoid is
OFF. There are several conditions that can result in
NO EMCC operations. No EMCC can be initiated
due to a fault in the transmission or because the
TCM does not see the need for EMCC under current
driving conditions.
PARTIAL EMCC
Partial EMCC operation modulates the L/R Sole-
noid (duty cycle) to obtain partial torque converter
clutch application. Partial EMCC operation is main-
tained until Full EMCC is called for and actuated.
During Partial EMCC some slip does occur. Partial
EMCC will usually occur at low speeds, low load and
light throttle situations.
FULL EMCC
During Full EMCC operation, the TCM increases
the L/R Solenoid duty cycle to full ON after PartialEMCC control brings the engine speed within the
desired slip range of transmission input speed rela-
tive to engine rpm.
GRADUAL-TO-NO EMCC
This operation is to soften the change from Full or
Partial EMCC to No EMCC. This is done at mid-
throttle by decreasing the L/R Solenoid duty cycle.
REMOVAL
(1) Remove transmission and torque converter
from vehicle.
(2) Place a suitable drain pan under the converter
housing end of the transmission.
CAUTION: Verify that transmission is secure on the
lifting device or work surface, the center of gravity
of the transmission will shift when the torque con-
verter is removed creating an unstable condition.
The torque converter is a heavy unit. Use caution
when separating the torque converter from the
transmission.
(3) Pull the torque converter forward until the cen-
ter hub clears the oil pump seal.
(4) Separate the torque converter from the trans-
mission.
INSTALLATION
Check converter hub and drive flats for sharp
edges, burrs, scratches, or nicks. Polish the hub and
flats with 320/400 grit paper or crocus cloth if neces-
sary. Verify that the converter hub o-ring is properly
installed and is free from debris. The hub must be
smooth to avoid damaging the pump seal at installa-
tion.
(1) Lubricate oil pump seal lip with transmission
fluid.
(2) Place torque converter in position on transmis-
sion.
CAUTION: Do not damage oil pump seal or con-
verter hub o-ring while inserting torque converter
into the front of the transmission.
(3) Align torque converter to oil pump seal open-
ing.
(4) Insert torque converter hub into oil pump.
(5) While pushing torque converter inward, rotate
converter until converter is fully seated in the oil
pump gears.
(6) Check converter seating with a scale and
straightedge (Fig. 117). Surface of converter lugs
should be at least 13 mm (1/2 in.) to rear of straight-
edge when converter is fully seated.
(7) If necessary, temporarily secure converter with
C-clamp attached to the converter housing.
Fig. 116 Stator Operation
1 - DIRECTION STATOR WILL FREE WHEEL DUE TO OIL
PUSHING ON BACKSIDE OF VANES
2 - FRONT OF ENGINE
3 - INCREASED ANGLE AS OIL STRIKES VANES
4 - DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING
AGAINST STATOR VANES
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 269
TORQUE CONVERTER (Continued)

(8) Install the transmission in the vehicle.
(9) Fill the transmission with the recommended
fluid.
TRANSMISSION CONTROL
RELAY
DESCRIPTION
The relay is supplied fused B+ voltage, energized
by the TCM, and is used to supply power to the sole-
noid pack when the transmission is in normal oper-
ating mode.
OPERATION
When the relay is ªoffº, no power is supplied to the
solenoid pack and the transmission is in ªlimp-inº
mode. After a controller reset, the TCM energizes the
relay. Prior to this, the TCM verifies that the con-
tacts are open by checking for no voltage at the
switched battery terminals. After this is verified, the
voltage at the solenoid pack pressure switches is
checked. After the relay is energized, the TCM mon-
itors the terminals to verify that the voltage is
greater than 3 volts.
TRANSMISSION RANGE
SENSOR
DESCRIPTION
The Transmission Range Sensor (TRS) is part of
the solenoid module, which is mounted to the top of
the valve body inside the transmission.
The Transmission Range Sensor (TRS) has five
switch contact pins that:
²Determine shift lever position
²Supply ground to the Starter Relay in Park and
Neutral only.
²Supply +12 V to the backup lamps in Reverse
only.
The TRS also has an integrated temperature sen-
sor (thermistor) that communicates transmission
temperature to the TCM and PCM.
OPERATION
The Transmission Range Sensor (TRS) communi-
cates shift lever position to the TCM as a combina-
tion of open and closed switches. Each shift lever
position has an assigned combination of switch states
(open/closed) that the TCM receives from four sense
circuits. The TCM interprets this information and
determines the appropriate transmission gear posi-
tion and shift schedule.
There are many possible combinations of open and
closed switches (codes). Seven of these possible codes
are related to gear position and five are recognized
as ªbetween gearº codes. This results in many codes
which shouldnever occur. These are called
ªinvalidº codes. An invalid code will result in a DTC,
and the TCM will then determine the shift lever
position based on pressure switch data. This allows
reasonably normal transmission operation with a
TRS failure.
GEAR C5 C4 C3 C2 C1
ParkCL OP OP CL CL
Temp 1CL OP OP CL OP
ReverseOP OP OP CL OP
Temp 2OP OP CL CL OP
Neutral 1OP OP CL CL CL
Neutral 2OP CL CL CL CL
Temp 3OP CL CL CL OP
DriveOP CL CL OP OP
Temp 4OP CL OP OP OP
Manual 2CL CL OP OP OP
Temp 5CL OP OP OP OP
Manual 1CL OP CL OP OP
Fig. 117 Checking Torque Converter Seating-Typical
1 - SCALE
2 - STRAIGHTEDGE
21 - 270 AUTOMATIC TRANSMISSION - 545RFEWJ
TORQUE CONVERTER (Continued)

TRANSMISSION SOLENOID/
TRS ASSEMBLY
DESCRIPTION
The transmission solenoid/TRS assembly is inter-
nal to the transmission and mounted on the valve
body assembly (Fig. 118). The assembly consists of
six solenoids that control hydraulic pressure to the
six friction elements (transmission clutches), and the
torque converter clutch. The pressure control sole-
noid is located on the side of the solenoid/TRS assem-
bly. The solenoid/TRS assembly also contains five
pressure switches that feed information to the TCM.
OPERATION
SOLENOIDS
Solenoids are used to control the L/R, 2C, 4C, OD,
and UD friction elements. The reverse clutch is con-
trolled by line pressure and the position of the man-
ual valve in the valve body. All the solenoids are
contained within the Solenoid and Pressure Switch
Assembly. The solenoid and pressure switch assembly
contains one additional solenoid, Multi-Select (MS),
which serves primarily to provide 2nd and 3rd gear
limp-in operation.The solenoids receive electrical power from the
Transmission Control Relay through a single wire.
The TCM energizes or operates the solenoids individ-
ually by grounding the return wire of the solenoid as
necessary. When a solenoid is energized, the solenoid
valve shifts, and a fluid passage is opened or closed
(vented or applied), depending on its default operat-
ing state. The result is an apply or release of a fric-
tional element.
The MS and UD solenoids are normally applied to
allow transmission limp-in in the event of an electri-
cal failure.
The continuity of the solenoids and circuits are
periodically tested. Each solenoid is turned on or off
depending on its current state. An inductive spike
should be detected by the TCM during this test. If no
spike is detected, the circuit is tested again to verify
the failure. In addition to the periodic testing, the
solenoid circuits are tested if a speed ratio or pres-
sure switch error occurs.
PRESSURE SWITCHES
The TCM relies on five pressure switches to moni-
tor fluid pressure in the L/R, 2C, 4C, UD, and OD
hydraulic circuits. The primary purpose of these
switches is to help the TCM detect when clutch cir-
cuit hydraulic failures occur. The switches close at 23
psi and open at 11 psi, and simply indicate whether
or not pressure exists. The switches are continuously
monitored by the TCM for the correct states (open or
closed) in each gear as shown in the following chart:
GEAR L/R 2C 4C UD OD
ROP OP OP OP OP
P/NCL OP OP OP OP
1STCL* OP OP CL OP
2NDOP CL OP CL OP
2ND
PRIMEOP OP CL CL OP
DOP OP OP CL CL
4THOP OP CL OP CL
5THOP CL OP OP CL
*L/R is closed if output speed is below 100 rpm in
Drive and Manual 2. L/R is open in Manual 1.
A Diagnostic Trouble Code (DTC) will set if the
TCM senses any switch open or closed at the wrong
time in a given gear.
Fig. 118 Transmission Solenoid/TRS Assembly
1 - PRESSURE CONTROL SOLENOID
2 - TRANSMISSION RANGE SELECTOR PLATE
3 - 23-WAY CONNECTOR
4 - SOLENOID PACK
5 - TRANSMISSION RANGE SENSOR
6 - VALVE BODY
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 271

VALVE BODY
DESCRIPTION
The valve body consists of a cast aluminum valve
body, a separator plate, and a transfer plate. The
valve body contains valves and check balls that con-
trol fluid delivery to the torque converter clutch,
bands, and frictional clutches. The valve body con-
tains the following components (Fig. 121) and (Fig.
122):
²Solenoid switch valve
²Manual valve
²Low/reverse switch valve
²5 Accumulators
²7 check balls
OPERATION
NOTE: Refer to the Hydraulic Schematics for a
visual aid in determining valve location, operation
and design.
SOLENOID SWITCH VALVE
The Solenoid Switch Valve (SSV) controls the direc-
tion of the transmission fluid when the L/R-TCC sole-
noid is energized.
The Solenoid Switch Valve controls line pressure
from the LR-TCC solenoid. In 1st gear, the SSV will
Fig. 121 Valve Body Components
1 - LOW/REVERSE ACCUMULATOR 6 - OVERDRIVE ACCUMULATOR
2 - LOW/REVERSE SWITCH VALVE 7 - UNDERDRIVE ACCUMULATOR
3 - UPPER VALVE BODY 8 - 4C ACCUMULATOR
4 - MANUAL VALVE 9 - 2C ACCUMULATOR
5 - SOLENOID SWITCH VALVE
Fig. 122 Check Ball Locations
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 273

be in the downshifted position, thus directing fluid to
the L/R clutch circuit. In 2nd, 3rd, 4th, and fifth
gears, the solenoid switch valve will be in the
upshifted position and directs the fluid into the
torque converter clutch (TCC) circuit.
When shifting into 1st gear, a special hydraulic
sequence is performed to ensure SSV movement into
the downshifted position. The L/R pressure switch is
monitored to confirm SSV movement. If the move-
ment is not confirmed (the L/R pressure switch does
not close), 2nd gear is substituted for 1st. A DTC will
be set after three unsuccessful attempts are made to
get into 1st gear in one given key start.
MANUAL VALVE
The manual valve is a relay valve. The purpose of
the manual valve is to direct fluid to the correct cir-
cuit needed for a specific gear or driving range. The
manual valve, as the name implies, is manually oper-
ated by the driver with a lever located on the top of
the valve body. The valve is connected mechanically
by a cable to the gearshift mechanism. The valve is
held in each of its positions by a roller detent spring
(Fig. 123) that engages the ªroostercombº of the TRS
selector plate.
LOW/REVERSE SWITCH VALVE
The low/reverse switch valve allows the low/reverse
clutch to be operated by either the LR/CC solenoid or
the MS solenoid.
REMOVAL
The valve body can be removed for service without
having to remove the transmission assembly.
The valve body can be disassembled for cleaning
and inspection of the individual components. (Refer
to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC
- 45RFE/VALVE BODY - DISASSEMBLY)
(1) Shift transmission into PARK.
(2) Raise vehicle.
(3) Disconnect wires at the solenoid and pressure
switch assembly connector.
(4) Position drain pan under transmission oil pan.
(5) Remove transmission oil pan.
(6) Remove the primary oil filter from valve body.
(Fig. 124)
Fig. 123 TRS Selector Plate and Detent Spring
1 - TRS SELECTOR PLATE
2 - DETENT SPRING
3 - CLUTCH PASSAGE SEALS
Fig. 124 Remove Primary Oil Filter
1 - PRIMARY OIL FILTER
2 - COOLER RETURN FILTER
3 - COOLER RETURN FILTER BYPASS VALVE
4 - VALVE BODY
21 - 274 AUTOMATIC TRANSMISSION - 545RFEWJ
VALVE BODY (Continued)

(8) Position the accumulator cover onto the valve
body.
(9) Install the screws to hold the accumulator
cover onto the valve body. Tighten the screws to 4.5
N´m (40 in. lbs.).
(10) Install the TRS selector plate onto the valve
body and the manual valve.
(11) Install the solenoid and pressure switch
assembly onto the valve body.
(12) Install the screws to hold the solenoid and
pressure switch assembly onto the valve body.
Tighten the screws to 5.7 N´m (50 in. lbs.). Tighten
the screws adjacent to the arrows cast into the bot-
tom of the transfer plate first.
(13) Position the detent spring onto the valve body.
(14) Install the screw to hold the detent spring
onto the valve body. Tighten the screw to 4.5 N´m (40
in. lbs.).
(15) Install new clutch passage seals onto the
valve body, if necessary
INSTALLATION
(1) Check condition of seals on valve body and the
solenoid and pressure switch assembly. Replace seals
if cut or worn.
(2) Place TRS selector plate in the PARK position.
(3) Place the transmission in the PARK position.
(4) Lubricate seal on the solenoid and pressure
switch assembly connector with petroleum jelly.(5) Position valve body in transmission and align
the manual lever on the valve body to the pin on the
transmission manual shift lever.
(6) Seat valve body in case and install one or two
bolts to hold valve body in place.
(7) Tighten valve body bolts alternately and evenly
to 12 N´m (105 in. lbs.) torque.
(8) Install a new primary oil filter seal in the oil
pump inlet bore. Seat the seal in the bore with the
butt end of a hammer, or other suitable tool.
CAUTION: The primary oil filter seal MUST be fully
installed flush against the oil pump body. DO NOT
install the seal onto the filter neck and attempt to
install the filter and seal as an assembly. Damage to
the transmission will result.
(9) Place replacement filter in position on valve
body and into the oil pump.
(10) Install screw to hold filter to valve body.
Tighten screw to 4.5 N´m (40 in. lbs.) torque.
(11) Connect the solenoid and pressure switch
assembly connector.
(12) Install oil pan. Tighten pan bolts to 12 N´m
(105 in. lbs.) torque.
(13) Lower vehicle and fill transmission with
MopartATF +4, type 9602, fluid.
(14) Check and adjust gearshift cable, if necessary.
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 279
VALVE BODY (Continued)

TRANSFER CASE - NV242
TABLE OF CONTENTS
page page
TRANSFER CASE - NV242
DESCRIPTION........................280
OPERATION..........................281
DIAGNOSIS AND TESTING - TRANSFER
CASE - NV242.......................281
REMOVAL............................282
DISASSEMBLY........................282
CLEANING...........................292
INSPECTION.........................293
ASSEMBLY...........................295
INSTALLATION........................307
SPECIFICATIONS
TRANSFER CASE - NV242.............308
SPECIAL TOOLS
TRANSFER CASE - NV242.............308
FLUID
STANDARD PROCEDURE - FLUID DRAIN/
REFILL............................310FRONT OUTPUT SHAFT SEAL
REMOVAL............................310
INSTALLATION........................310
POSITION SENSOR
DESCRIPTION........................311
OPERATION..........................311
REMOVAL............................312
INSTALLATION........................312
REAR RETAINER BUSHING AND SEAL -
NV242HD
REMOVAL............................312
INSTALLATION........................312
SHIFT CABLE
REMOVAL............................313
INSTALLATION........................313
TRANSFER CASE - NV242
DESCRIPTION
The NV242 is a full transfer case (Fig. 1). It pro-
vides full time 2-wheel, or 4-wheel drive operation.
A differential in the transfer case is used to control
torque transfer to the front and rear axles. A low
range gear provides increased low speed torque capa-
bility for off road operation. The low range provides a
2.72:1 reduction ratio.
The geartrain is mounted in two aluminum case
halves attached with bolts. The mainshaft front and
rear bearings are mounted in aluminum retainer
housings bolted to the case halves.
TRANSFER CASE IDENTIFICATION
Two versions of the NV242 are used in the WJ
vehicles, NV242LD and NV242HD. The two transfer
cases can be distinguished from one another by the
rear output shaft retainer. The NV242LD uses a rub-
ber boot to cover the rear output shaft, while the
NV242HD uses a cast aluminum housing. Other than
this difference, the two transfer cases are serviced
the same.
A circular ID tag is attached to the rear case of
each transfer case (Fig. 2). The ID tag provides the
transfer case model number, assembly number, serial
number, and low range ratio.The transfer case serial number also represents
the date of build.
SHIFT MECHANISM
Operating ranges are selected with a lever in the
floor mounted shifter assembly. The shift lever is con-
nected to the transfer case range lever by an adjust-
able cable. A straight line shift pattern is used.
Range positions are marked on the shifter bezel.
Fig. 1 NV242 Transfer Case
21 - 280 TRANSFER CASE - NV242WJ

OPERATION
The input gear is splined to the transmission out-
put shaft. It drives the mainshaft through the plan-
etary gear and range hub. The front output shaft is
operated by a drive chain that connects the shaft to a
drive sprocket on the mainshaft. The drive sprocket
is engaged/disengaged by the mode fork, which oper-
ates the mode sleeve and hub. The sleeve and hub
are not equipped with a synchro mechanism for shift-
ing.
OPERATING RANGES
NV242 operating ranges are 2WD (2-wheel drive),
4x4 part-time, 4x4 full time, and 4 Lo.
The 2WD and 4x4 full time ranges can be used at
any time and on any road surface.
The 4x4 part-time and 4 Lo ranges are for off road
use only. The only time these ranges can be used on
hard surface roads, is when the surface is covered
with snow and ice.
DIAGNOSIS AND TESTING - TRANSFER CASE - NV242
DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
Transfer case difficult to shift or will
not shift into desired range.1) Transfer case shift linkage
binding.1) Repair or replace linkage as
necessary.
2) Insufficient or incorrect lubricant. 2) Drain and refill transfer case with
the correct type and quantity of
lubricant.
3) Internal transfer case
components binding, worn, or
damaged.3) Repair or replace components as
necessary.
Transfer case noisy in all drive
modes.1) Insufficient or incorrect lubricant. 1) Drain and refill transfer case with
the correct type and quantity of
lubricant.
Lubricant leaking from transfer case
seals or vent.1) Transfer case overfilled. 1) Drain lubricant to the correct
level.
2) Transfer case vent closed or
restricted.2) Clean or replace vent as
necessary.
3) Transfer case seals damaged or
installed incorrectly.3) Replace suspect seal.
Transfer case will not shift through
4X4 part time range (light remains
on)1) Incomplete shift due to drivetrain
torque load.1) Momentarily release the
accelerator pedal to complete the
shift.
2) Incorrect tire pressure. 2) Correct tire pressure as
necessary.
3) Excessive Tire wear. 3) Correct tire condition as
necessary.
4) Excessive vehicle loading. 4) Correct as necessary.
Fig. 2 Fill/Drain Plug And I.D. Tag Locations
1 - I.D. TAG
2 - FILL PLUG
3 - DRAIN PLUG
WJTRANSFER CASE - NV242 21 - 281
TRANSFER CASE - NV242 (Continued)

(5) Align and position differential top case on bot-
tom case (Fig. 67). Align using scribe marks made at
disassembly.
(6) While holding differential case halves together,
invert the differential and start the differential case
bolts.
(7) Tighten differential case bolts to specified
torque.
INPUT GEAR/LOW RANGE ASSEMBLY
(1) Assemble low range gear, input gear thrust
washers, input gear and input gear retainer (Fig. 68).
(2) Install low range gear snap ring (Fig. 69).
(3) Lubricate input gear and low range gears with
automatic transmission fluid.
(4) Start input gear shaft into front case bearing.
(5) Press input gear shaft into front bearing.
(6) Install new input gear snap ring (Fig. 70).
(7) Apply 3 mm (1/8 in.) wide bead of Mopartgas-
ket maker or silicone adhesive sealer to seal surface
of front bearing retainer.
(8) Install front bearing retainer (Fig. 71). Tighten
retainer bolts to 16 ft. lbs. (21 N´m) torque.
SHIFT FORKS, SECTOR, AND MAINSHAFT
(1) Install the shift sector shaft o-ring and bush-
ing.
(2) Install shift sector.(3) Install new pads on low range fork, if neces-
sary.
(4) Assemble low range fork and sleeve.
Fig. 67 Differential Case Assembly
1 - TOP CASE
2 - BOTTOM CASE
3 - CASE ALIGNMENT MARKS
Fig. 68 Low Range And Input Gear Assembly
1 - THRUST WASHERS
2 - LOW RANGE GEAR
3 - INPUT GEAR
4 - RETAINER
Fig. 69 Install Low Range Gear Snap-Ring
1 - LOW RANGE GEAR SNAP-RING
21 - 300 TRANSFER CASE - NV242WJ
TRANSFER CASE - NV242 (Continued)