REAR EXTENSION
1. Install new seal in rear extension housing seal with
Installer D-163 and Universal Handle C-4171..
2. Apply bead of Mopar
Gasket Maker, or equivalent,
to mating surface of rear extension housing. Keep
sealer bead width to maximum of 3/16 inch. Do not
use excessive amount of sealer as excess could
be displaced into output bearing.
3. Align and install rear extension (1) on the transfer
case (2).
4. Apply Mopar
Silicone Sealer to threads of rear
extension housing bolts. Then install and tighten
bolts to 16-24 Nꞏm (12-18 ft. lbs.) torque.
INSTALLATION
1. Mount transfer case on a transmission jack.
2. Secure transfer case to jack with chains.
3. Position transfer case under vehicle.
4. Align transfer case and transmission shafts and install transfer case onto the transmission.
5. Install and tighten transfer case attaching nuts to 27-34 Nꞏm (20-25 ft.lbs.) torque.
6. Connect the vent hose.
7. Connect the shift motor and mode sensor wiring connectors. Secure wire harness to clips on transfer case.
8. Align and connect the propeller shafts. (Refer to 3 - DIFFERENTIAL & DRIVELINE/PROPELLER SHAFT/FRONT
PROPELLER SHAFT - INSTALLATION) (Refer to 3 - DIFFERENTIAL & DRIVELINE/PROPELLER SHAFT/REAR
PROPELLER SHAFT - INSTALLATION)
9. Fill transfer case with correct fluid. (Refer to 21 - TRANSMISSION/TRANSFER CASE/FLUID - STANDARD PRO-
CEDURE)
10. Install skid plate, if equipped.
11. Remove transmission jack and support stand.
12. Lower vehicle and verify transfer case shift operation.
SPECIFICATIONS
TRANSFER CASE - NV243
TORQUE SPECIFICATIONS
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Plug, Detent 16-24 12-18 -
Plug, Drain/Fill 20-34 15-25 -
Bolt, Extension Housing 16-24 12-18 -
Bolt, Case Half 20-27 15-24 -
Screw, Oil Pump 12-16 8-12 -
Nuts, Mounting 30-41 20-30 -
Bolts, Shift Motor and
Mode Sensor Assembly16-24 12-18 -
SENSOR-MODE
DESCRIPTION
The transfer case mode sensor (1) is an electronic
device whose output can be interpreted to indicate the
shift motor shaft’s rotary position. The sensor consists
of a magnetic ring and four Hall Effect Transistors to
create a 4 channel digital device (non-contacting)
whose output converts the motor shaft position into a
coded signal. The TCCM must supply 5VDC (+/- 0.5v)
to the sensor and monitor the shift motor position. The
four channels are denoted A, B, C, and D. The sensor
is mechanically linked to the shaft of the cam which
causes the transfer case shifting. The mode sensor
draws less than 53 mA.
OPERATION
During normal vehicle operation, the Transfer Case Control Module (TCCM)monitors the mode sensor outputs at
least every 250 (+/-50) milliseconds when the shift motor is stationary and 400 microseconds when the shift motor
is active. A mode sensor signal between 3.8 Volts and 0.8 Volts is considered to be undefined.
Refer to SECTOR ANGLES vs. TRANSFER CASE POSITION for the relative angles of the transfer case shift sector
versus the interpreted transfer case gear operating mode. Refer to MODE SENSOR CHANNEL STATES for the
sensor codes returned to the TCCM for each transfer case mode sensor position. The various between gears posi-
tions can also be referred as the transfer case’s coarse position. These coarse positions come into play during shift
attempts.
SECTOR ANGLES vs. TRANSFER CASE POSITION
Shaft Angle (Degrees) Transfer Case Position
+40 4LO
+20 N
0 2WD/AWD
-20 4HI
MODE SENSOR CHANNEL STATES
Transfer Case
Angle (degrees)Sensor Channel A Sensor Channel B Sensor Channel C Sensor Channel D
Between Gears H H L H
+40 (4LO) H H L L
Between Gears H H L H
Between Gears H L L H
+20 (NEUTRAL) H L L L
Between Gears H L L H
Between Gears H L H H
Transfer Case
Angle (degrees)Sensor Channel A Sensor Channel B Sensor Channel C Sensor Channel D
0 (2WD/AWD) H L H L
Between Gears H L H H
Between Gears L L H H
-20 (4HI) L L H L
Between Gears L L H H
Between Gears L H H H
SWITCH-SELECTOR
DESCRIPTION
The selector switch assembly is mounted in the left
side of the vehicle’s Instrument Panel (IP) and con-
sists of a rotary knob connected to a resistive network
for the mode and range shift selections. Also located
in this assembly is a recessed, normally open momen-
tary switch for making shifts into and out of transfer
case NEUTRAL. A pen, or similar instrument, is used
to make a NEUTRAL shift selection, thus reducing the
likelihood of an inadvertent shift request.
The selector switch also contains four light emitting
diode’s (LED’s) to indicate the transfer case position
and whether a shift is in progress.
OPERATION
As the position of the selector switchvaries, the resistance between the Mode Sensor supply voltage pin and the
Mode Sensor output will vary. Hardware, software, and calibrations within the Transfer Case Control Module
(TCCM) are provided that interpret the selector switch resistance as giveninthetablebelow:SELECTORSWITCH
INTERPRETATION
SELECTOR SWITCH INTERPRETATION
Step Resistance Range (ohms) Required Interpretation
A <200 Shorted
B 400-700 NEUTRAL
C 1050-1450 4LO
D 1850-2300 4HI
E 3050-5950 2WD (Default)
F 9.5-12.5K In between positions
G>15.5KOpen
For resistances between the ranges B-E shown for each valid position (T-Case NEUTRAL, 4LO, 4HI, 2WD), the
TCCM may interpret the resistance as:
either of the neighboring valid positions.
as an invalid fault position.
For resistances between the ranges E and F shown for 2WD and in-between positions, the TCCM may interpret the
resistance as:
the 2WD position.
an invalid fault position.
a valid in-between position.
For resistances between the ranges F and G shown for in-between positions and fault condition (open), the TCCM
may interpret the resistance as:
a valid in-between position.
an invalid fault position.
MOTOR-SHIFT
DESCRIPTION
The shift motor (1) consists of a permanent magnet
D.C. motor with gear reduction to convert a high
speed-low torque device into a low speed-high torque
device. The output of the device is coupled to a shaft
which internally moves the mode and range forks that
change the transfer case operating ranges. The motor
is rated at 25 amps maximum at (23° C (72° F) with
10 volts at the motor leads.
OPERATION
The transfer case shift motor responds to the Transfer Case Control Module(TCCM) commands to move the trans-
fer case shift sector bi-directionally, as required, to obtain the transfer case operating mode indicated by the instru-
ment panel mounted selector switch.
REMOVAL
NOTE: New shift motor assemblies are shipped in the 2WD/AWD position. If a new shift motor assembly will
be installed, it will be necessary to shift the transfer case to the 2WD/AWDposition prior to motor removal.
1. Raise the vehicle on a suitable hoist.
2. Disengage the wiring connectors from the shift motor and mode sensor.
3. Remove the bolts holding the shift motor and mode sensor assembly onto the transfer case.
4. Separate the shift motor and mode sensor assembly from the transfer case.
INSTALLATION
1. Verify that the shift sector o-ring is clean and properly positioned over the shift sector and against the transfer
case.
NOTE: Verify that the shift motor position and sector shaft orientation are aligned. It may be necessary to
manually shift the transfer case if the shift motor and sector shaft are notaligned.
2. Position the shift motor and mode sensor assembly onto the transfer case.
3. Install the bolts to hold the assembly onto the transfer case. Tighten the bolts to 16-24 Nꞏm (12-18 ft.lbs.).
CAUTION: If the original shift motor and mode sensor assembly bolts are reused, be sure to use Mopar
Lock & Seal or Loctite™ 242 to replenish the lock patch material originallyfound on the bolts
4. Engage the wiring connectors to the shift motor and mode sensor.
5. Refill the transfer case as necessary.
ASSEMBLY-SHIFT MOTOR/MODE SENSOR
DESCRIPTION
The shift motor (1) consists of a permanent magnet
D.C. motor with gear reduction to convert a high
speed-low torque device into a low speed-high torque
device. The output of the device is coupled to a shaft
which internally moves the mode and range forks that
change the transfer case operating ranges. The motor
is rated at 25 amps maximum at (23° C (72° F) with
10 volts at the motor leads.
OPERATION
The transfer case shift motor responds to the Transfer Case Control Module(TCCM) commands to move the trans-
fer case shift sector bi-directionally, as required, to obtain the transfer case operating mode indicated by the instru-
ment panel mounted selector switch.
page page
TRANSFER CASE - NV244 GENII - SERVICE
INFORMATION
DESCRIPTION ............................. 1701
OPERATION ............................... 1701
DIAGNOSIS AND TESTING
TRANSFER CASE - NV244 ................ 1702
REMOVAL ................................. 1703
DISASSEMBLY ............................. 1703
CLEANING ................................. 1715
INSPECTION ............................... 1715
ASSEMBLY . ............................... 1718
INSTALLATION ............................. 1730
SPECIFICATIONS
TRANSFER CASE - NV244 GENII .......... 1730
SPECIAL TOOLS
TRANSFER CASE - NV244 GENII .......... 1731
SEAL-EXTENSION HOUSING
REMOVAL ................................. 1733INSTALLATION ............................. 1733
FLUID
STANDARD PROCEDURE - FLUID DRAIN AND
REFILL ................................... 1734
SEAL-FRONT OUTPUT SHAFT
REMOVAL ................................. 1735
INSTALLATION ............................. 1736
SENSOR-MODE
DESCRIPTION ............................. 1737
OPERATION ............................... 1737
SWITCH-TRANSFER CASE SELECTOR
DESCRIPTION ............................. 1739
OPERATION ............................... 1739
MOTOR-SHIFT
DESCRIPTION ............................. 1741
OPERATION ............................... 1741
REMOVAL ................................. 1741
INSTALLATION ............................. 1741
TRANSFER CASE - NV244 GENII - SERVICE INFORMATION
DESCRIPTION
The NV244 GENII is an electronically controlled full and part-time transfer case with no two 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
reduction system provides increased low speed torque capability 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.
OPERATING RANGES
NV244 GENII operating ranges are:
AWD (All-Wheel Drive).
4LOCK (Part-time).
4LO.
NEUTRAL.
The AWD mode can be used at any time and on any road surface.
The 4LOCK (Part-time) and 4LO ranges are for off road use only. The only timetheserangescanbeusediswhen
the road surface is covered with snow, ice, or other loose slippery material.
SHIFT MECHANISM
Operating ranges are selected with a dash mounted shift selector switch. The shift selector switch provides a input
to the Front Control Module (FCM) to indicate the driver’s desire to changeoperating ranges. The FCM uses this
input, along with the input from the transfer case mounted mode sensor and information from the vehicle’s bus, to
determine if a shift is permitted. If the FCM decides the shift is permitted, the FCM controls the shift motor, mounted
to the exterior of the transfer case, to perform the shift.
IDENTIFICATION
A circular ID (1) tag is attached to the rear case of
each transfer case. 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.
OPERATION
The input gear is splined to the transmission output shaft. The input gear drives the mainshaft through the planetary
assembly and range sleeve. 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 splined to a differentialassembly. Depending on the position of the
mode fork and sleeve, the front output shaft is driven directly by the mainshaft or through the differential. The mode
fork operates the mode sleeve and hub. The sleeve and hub are not equipped with a synchronizer mechanism for
shifting.