2003 JEEP GRAND CHEROKEE Drive train

TRANSMISSION IDENTIFICATION
Transmission identification numbers are stamped
on the left side of the case just above the oil pan
sealing surface (Fig. 1). Refer to this information
when ordering replacement parts. A label is attached
to the transmission case above the stamped numbers.
The label gives additional information which may
also be necessary for identification purposes.
GEAR RATIOS The 545RFE gear ratios are:
1st .................................3.00:1
2nd.................................1.67:1
2nd Prime............................1.50:1
3rd .................................1.00:1
4th .................................0.75:1
5th .................................0.67:1
Reverse..............................3.00:1
OPERATION
The 545RFE offers full electronic control of all auto-
matic up and downshifts, and features real-time adap-
tive closed-loop shift and pressure control. Electronic
shift and torque converter clutch controls help protect
the transmission from damage due to high tempera-
tures, which can occur under severe operating condi-
tions. By altering shift schedules, line pressure, and
converter clutch control, these controls reduce heat gen-
eration and increase transmission cooling.
To help reduce efficiency-robbing parasitic losses,
the transmission includes a dual-stage transmission
fluid pump with electronic output pressure control.
Under most driving conditions, pump output pres-
sure greatly exceeds that which is needed to keep the
clutches applied. The 545RFE pump-pressure controlsystem monitors input torque and adjusts the pump
pressure accordingly. The primary stage of the pump
works continuously; the second stage is bypassed
when demand is low. The control system also moni-
tors input and output speed and, if incipient clutch
slip is observed, the pressure control solenoid duty
cycle is varied, increasing pressure in proportion to
demand.
A high-travel torque converter damper assembly
allows earlier torque converter clutch engagement to
reduce slippage. Needle-type thrust bearings reduce
internal friction. The 545RFE is packaged in a one-
piece die-cast aluminum case. To reduce NVH, the
case has high lateral, vertical and torsional stiffness.
It is also designed to maximize the benefit of the
structural dust cover that connects the bottom of the
bell housing to the engine bedplate, enhancing over-
all power train stiffness. Dual filters protect the
pump and other components. A pump return filter is
added to the customary main sump filter. Indepen-
dent lubrication and cooler circuits assure ample
pressure for normal transmission operation even if
the cooler is obstructed or the fluid cannot flow due
to extremely low temperatures.
The hydraulic control system design (without elec-
tronic assist) provides the transmission with PARK,
REVERSE, NEUTRAL, SECOND, and THIRD gears,
based solely on driver shift lever selection. This
design allows the vehicle to be driven (in ªlimp-inº
mode) in the event of a electronic control system fail-
ure, or a situation that the Transmission Control
Module (TCM) recognizes as potentially damaging to
the transmission.
The TCM also performs certain self-diagnostic
functions and provides comprehensive information
(sensor data, DTC's, etc.) which is helpful in proper
diagnosis and repair. This information can be viewed
with the DRB scan tool.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AUTOMATIC
TRANSMISSION
CAUTION: Before attempting any repair on a
545RFE automatic transmission, check for Diagnos-
tic Trouble Codes with the DRBTscan tool.
Transmission malfunctions may be caused by these
general conditions:
²Poor engine performance
²Improper adjustments
²Hydraulic malfunctions
²Mechanical malfunctions
²Electronic malfunctions
Fig. 1 Transmission Part And Serial Number
Location
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 179
AUTOMATIC TRANSMISSION - 545RFE (Continued)

STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can inter-
fere with normal valve, clutch, and accumulator opera-
tion. Foaming can also result in fluid escaping from the
transmission vent where it may be mistaken for a leak.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
The transmission has a dipstick to check oil level.
It is located on the right side of the engine. Be sure
to wipe all dirt from dipstick handle before removing.
The torque converter fills in both the P (PARK)
and N (NEUTRAL) positions. Place the selector lever
in P (PARK) to be sure that the fluid level check is
accurate.The engine should be running at idle
speed for at least one minute, with the vehicle
on level ground.At normal operating temperature(approximately 82 C. or 180 F.), the fluid level is cor-
rect if it is in the HOT region (cross-hatched area) on
the oil level indicator. The fluid level will be approx-
imately at the upper COLD hole of the dipstick at
70É F fluid temperature.
NOTE: Engine and Transmission should be at nor-
mal operating temperature before performing this
procedure.
(1) Start engine and apply parking brake.
(2) Shift the transmission into DRIVE for approxi-
mately 2 seconds.
(3) Shift the transmission into REVERSE for
approximately 2 seconds.
(4) Shift the transmission into PARK.
(5)
Hook up DRBtscan tool and select transmission.
(6) Select sensors.
(7) Read the transmission temperature value.
(8) Compare the fluid temperature value with the
chart. (Fig. 59)
(9) Adjust transmission fluid level shown on the
dipstick according to the chart.
NOTE: After adding any fluid to the transmission,
wait a minimum of 2 minutes for the oil to fully
drain from the fill tube into the transmission before
rechecking the fluid level.
(10) Check transmission for leaks.
Fig. 59 Transmission Fluid Temperature Chart
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 229
FLUID AND FILTER (Continued)

HOLDING CLUTCHES
DESCRIPTION
Three hydraulically applied multi-disc clutches are
used to hold some planetary geartrain components
stationary while the input clutches drive others. The
2C, 4C, and Low/Reverse clutches are considered
holding clutches. The 2C and 4C clutches are located
in the 4C retainer/bulkhead (Fig. 66), while the Low/
Reverse clutch is located at the rear of the transmis-
sion case (Fig. 67).
Fig. 66 2C and 4C Clutches
1 - SEAL 8 - REACTION PLATE
2 - 2C PISTON 9 - SNAP-RING
3 - PLATE 10 - RETURN SPRING
4 - DISC 11 - SEAL
5 - 2C BELLEVILLE SPRING 12 - 4C PISTON
6 - SNAP-RING 13 - 4C RETAINER/BULKHEAD
7 - SNAP-RING (SELECT)
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 233

INPUT CLUTCH ASSEMBLY
DESCRIPTION
Three hydraulically applied input clutches are used
to drive planetary components. The underdrive, over-
drive, and reverse clutches are considered input
clutches and are contained within the input clutch
assembly (Fig. 68) and (Fig. 69). The input clutch
assembly also contains:
²Input shaft
²Input hub
²Clutch retainer
²Underdrive piston²Overdrive/reverse piston
²Overdrive hub
²Underdrive hubOPERATION
The three input clutches are responsible for driving
different components of the planetary geartrain.
UNDERDRIVE CLUTCH
The underdrive clutch is hydraulically applied in
first, second, second prime, and third (direct) gears
by pressurized fluid against the underdrive piston.
Fig. 68 Input Clutch Assembly - Part 1
1 - INPUT CLUTCH HUB 11 - UD CLUTCH
2 - O-RING SEALS 12 - PLATE
3 - SEAL 13 - CLUTCH RETAINER
4 - SNAP-RING 14 - SEAL
5 - SNAP-RING 15 - OD/REV PISTON
6 - UD BALANCE PISTON 16 - BELLEVILLE SPRING
7 - SNAP-RING 17 - SNAP-RING
8 - UD PISTON 18 - SEAL RINGS
9 - SPRING 19 - INPUT SHAFT
10 - DISC 20 - LUBRICATION CHECK VALVE AND SNAP-RING
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 235

OPERATION
REACTION PLANETARY GEARTRAIN
The reaction planetary carrier and reverse sun
gear of the reaction planetary geartrain are a single
component which is held by the 2C clutch when
required. The reaction annulus gear is a stand alone
component that can be driven by the reverse clutch
or held by the 4C clutch. The reaction sun gear is
driven by the overdrive clutch.
REVERSE PLANETARY GEARTRAIN
The reverse planetary geartrain is the middle of
the three planetary sets. The reverse planetary car-
rier can be driven by the overdrive clutch as
required. The reverse planetary carrier is also
splined to the input annulus gear, which can be held
by the low/reverse clutch. The reverse planetary
annulus, input planetary carrier, and output shaft
are all one piece.
INPUT PLANETARY GEARTRAIN
The input sun gear of the input planetary
geartrain is driven by the underdrive clutch.
DISASSEMBLY
(1) Remove the snap-ring holding the input annu-
lus into the input carrier (Fig. 104).
(2) Remove the input annulus from the input car-
rier (Fig. 104).
(3) Remove the number 9 bearing from the reverse
planetary carrier. Note that this planetary carrier
has four pinion gears.
(4) Remove the reverse planetary gear carrier (Fig.
104).
(5) Remove the number 10 bearing from the input
sun gear (Fig. 104).
(6) Remove the input sun gear from the input car-
rier (Fig. 104).
(7) Remove the number 11 bearing from the input
carrier (Fig. 104).
CLEANING
Clean the planetary components in solvent and dry
them with compressed air.
INSPECTION
Check sun gear and driving shell condition.
Replace the gear if damaged or if the bushings are
scored or worn. The bushings are not serviceable.
Fig. 104 Reverse/Input Planetary Carrier Assembly
1 - SNAP-RING 5 - INPUT PLANETARY CARRIER
2 - BEARING NUMBER 10 6 - INPUT SUN GEAR
3 - BEARING NUMBER 11 7 - REVERSE PLANETARY CARRIER
4 - INPUT ANNULUS
21 - 260 AUTOMATIC TRANSMISSION - 545RFEWJ
PLANETARY GEARTRAIN (Continued)

Replace the driving shell if worn, cracked or dam-
aged.
Replace planetary gear sets if gears, pinion pins, or
carrier are damaged in any way. Replace the annulus
gears and supports if either component is worn or
damaged.
Replace the output shaft if the machined surfaces
are scored, pitted, or damaged in any way. Also
replace the shaft if the splines are damaged, or
exhibits cracks at any location.
ASSEMBLY
(1) Clean and inspect all components. Replace any
components which show evidence of excessive wear
or scoring.
(2) Install the number 11 bearing into the input
planetary carrier so that the inner race will be
toward the front of the transmission (Fig. 104).
(3) Install the input sun gear into the input carrier
(Fig. 104).
(4) Install the number 10 bearing onto the rear of
the reverse planetary carrier with the inner race
toward the carrier (Fig. 104).
(5) Install the number 9 bearing onto the front of
the reverse planetary carrier with the outer race
toward the carrier and the inner race facing upward
(Fig. 104).
(6) Install the reverse planetary gear carrier into
the input carrier (Fig. 104).
(7) Install the input annulus gear into the input
carrier (Fig. 104).
(8) Install the snap-ring to hold the input annulus
gear into the input carrier (Fig. 104).
SHIFT MECHANISM
DESCRIPTION
The gear shift mechanism provides six shift posi-
tions which are:
²Park (P)
²Reverse (R)
²Neutral (N)
²Drive (D)
²Manual second (2)
²Manual low (1)
OPERATION
MANUAL LOW (1) range provides FIRST gear
only. Overrun braking is also provided in this range.
MANUAL SECOND (2) range provides FIRST and
SECOND gear only.
DRIVE range provides FIRST, SECOND, THIRD
and OVERDRIVE FOURTH and FIFTH gear ranges.
The shift into OVERDRIVE FOURTH and FIFTH
gear range occurs only after the transmission hascompleted the shift into D THIRD gear range. No
further movement of the shift mechanism is required
to complete the 3-4 or 4-5 shifts.
The FOURTH and FIFTH gear upshifts occurs
automatically when the overdrive selector switch is
in the ON position. An upshift to FOURTH and
FIFTH gears may not occur or may be delayed in
some of the possible shift schedules. (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/TRANSMISSION CONTROL MODULE -
OPERATION)
REMOVAL
(1) Remove any necessary console parts for access
to shift lever assembly and shifter cables. (Refer to
23 - BODY/INTERIOR/FLOOR CONSOLE -
REMOVAL)
(2) Shift transmission into PARK.
(3) Disconnect the transmission shift cable at shift
lever and shifter assembly bracket (Fig. 105).
(4) Disconnect the park lock cable from the shifter
BTSI lever and the shifter assembly bracket. (Fig.
106)
(5) Disconnect the transfer case shift cable from
the transfer case shift lever pin (Fig. 107), if
equipped.
(6) Remove the clip holding the transfer case shift
cable to the shifter assembly bracket, if equipped.
(7) Remove the transfer case shift cable from the
shifter assembly bracket, if equipped.
(8) Disengage all wiring connectors from the
shifter assembly.
(9) Remove all nuts holding the shifter assembly to
the floor pan (Fig. 108).
Fig. 105 Transmission Shift Cable
1 - SHIFT LEVER PIN
2 - ADJUSTMENT SCREW
3 - SHIFT CABLE
4 - SHIFTER ASSEMBLY BRACKET
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 261
PLANETARY GEARTRAIN (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)