Shifting DODGE RAM 1500 1998 2.G Owner's Guide

MODE SENSOR
DESCRIPTION
The transfer case mode sensor (Fig. 83) is an elec-
tronic device whose output can be interpreted to indi-
cate 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 CHAN-
NEL STATES for the sensor codes returned to the
TCCM for each transfer case mode sensor position.
The various between gears positions 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
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
Fig. 83 Mode Sensor
1 - MODE SENSOR
DRTRANSFER CASE - NV243 21 - 509

²A flashing operating mode LED for the desired
gear indicates that a shift to that position has been
requested, but all of the driver controllable conditions
have not been met. This is in an attempt to notify the
driver that the transmission needs to be put into NEU-
TRAL, the vehicle speed is too great, or some other con-
dition outlined (other than a diagnostic failure that
would prevent this shift) elsewhere (Refer to 8 - ELEC-
TRICAL/ELECTRONIC CONTROL MODULES/TRANS-
FER CASE CONTROL MODULE - OPERATION) is not
met. Note that this flashing will continue indefinitely
until the conditions are eventually met, or the selector
switch position is changed, or if diagnostic routines no
longer allow the requested shift.
²If the driver attempts to make a shift into transfer
case NEUTRAL, and any of the driver controllable con-
ditions are not met, the request will be ignored until all
of the conditions are met or until the NEUTRAL select
button is released. Additionally the neutral lamp will
flash, or begin to flash while the button is depressed
and operator controllable conditions are not being met.
All of the LED's except the Neutral will flash if any of
the operator controllable conditions for shifting are not
met while the Neutral button is depressed. This9toggle9
type of feature is necessary because the TCCM would
interpret another request immediately after the shift
into transfer case NEUTRAL has completed.
²No LED's illuminated indicate a fault in the
transfer case control system.
SHIFT MOTOR
DESCRIPTION
The shift motor (Fig. 85) 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 72É 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
transfer case shift sector bi-directionally, as required, to
obtain the transfer case operating mode indicated by
the instrument 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/AWD position 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 sec-
tor shaft orientation are aligned. It may be neces-
sary to manually shift the transfer case if the shift
motor and sector shaft are not aligned.
(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 N´m (12-18
ft.lbs.).
CAUTION: If the original shift motor and mode sen-
sor assembly bolts are reused, be sure to use
MoparTLock & Seal or LoctiteŸ 242 to replenish
the lock patch material originally found on the bolts
(4) Engage the wiring connectors to the shift motor
and mode sensor.
(5) Refill the transfer case as necessary.
(6) Lower vehicle and verify transfer case opera-
tion.
Fig. 85 Shift Motor - Shown Inverted - Typical
1 - SHIFT MOTOR
DRTRANSFER CASE - NV243 21 - 511
SELECTOR SWITCH (Continued)

IDENTIFICATION
A circular ID tag is attached to the rear case of
each transfer case (Fig. 1). 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 out-
put 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 differ-
ential assembly. 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 synchro-
nizer mechanism for shifting.
DIAGNOSIS AND TESTING - TRANSFER CASE - NV244
DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
Transfer case difficult to shift or will
not shift into desired range.1) Transfer case electronically
controlled shift system malfunction.1) Verify proper operation per the
appropriate diagnostic manual.
2) Insufficient or incorrect lubricant. 2) Drain and refill transfer case with
the correct quantity of MoparTAT F
+4, Automatic Transmission Fluid.
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 quantity of MoparTAT F
+4, Automatic Transmission Fluid.
2) Internal transfer case
components binding, worn, or
damaged.2) Repair or replace components as
necessary.
Transfer case noisy while in, or
jumps out of, 4LO.1) Transfer case not completely
engaged in 4LO position.1) While rolling 2-3 MPH and the
transmission in NEUTRAL, or the
clutch depressed on vehicles
equipped with a manual
transmission, shift the transfer case
to the AWD or 4HI position, and
then back into the 4LO position.
2) Range fork damaged, inserts
worn, or fork is binding on the shift
rail.2) Repair or replace components as
necessary.
3) Low range gear worn or
damaged.3) Repair or replace components as
necessary.
Fig. 1 Fill/Drain Plug And I.D. Tag Locations
1 - I.D. TAG
2 - FILL PLUG
3 - DRAIN PLUG
DRTRANSFER CASE - NV244 GENII 21 - 513
TRANSFER CASE - NV244 GENII (Continued)

(4) Remove the front output shaft seal slinger by
bending (Fig. 83) the slinger away from the transfer
case.
(5) Using a suitable pry tool, remove the slinger
from the output shaft using care not to damage the
shaft.
(6) Using a screw and a slide hammer, remove the
front output shaft seal.
INSTALLATION
(1) Install the new front output shaft seal with
Installer MB991168A
(2) Install the front output shaft seal slinger with
Installer 8840. Install the slinger onto the shaft until
the tool contacts the rear of the output shaft.
(3) Install a new seal boot clamp onto the seal
boot.
(4) Install the seal boot and clamp onto the slinger
hub and tighten the clamp with Crimp Tool
C-4975-A.
(5) Install front propeller shaft (Refer to 3 - DIF-
FERENTIAL & DRIVELINE/PROPELLER SHAFT/
PROPELLER SHAFT - INSTALLATION).
MODE SENSOR
DESCRIPTION
The transfer case mode sensor (Fig. 84) is an elec-
tronic device whose output can be interpreted to indi-
cate 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.
Fig. 83 Bend Slinger Upward
1 - SEAL SLINGER
2 - BEND UPWARD
Fig. 84 Mode Sensor - Typical
1 - MODE SENSOR
21 - 538 TRANSFER CASE - NV244 GENIIDR
FRONT OUTPUT SHAFT SEAL (Continued)

OPERATION
As the position of the selector switch varies, 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 given in the table
below: SELECTOR SWITCH INTERPRETATION
SELECTOR SWITCH INTERPRETATION
Step Resistance
Range (ohms)Required
Interpretation
A <200 Shorted
B 400-700 NEUTRAL
C 1050-1450 4LO
D 1850-2300 4H
E 3050-5950 AWD (Default)
F 9.5-12.5K In between
positions
G >15.5K Open
For resistances between the ranges B-E shown for
each valid position (T-Case NEUTRAL, 4LO, 4HI,
AWD), the TCCM may interpret the resistance as:
²either of the neighboring valid positions.
²as an invalid fault position.
For resistances between the ranges E and F shown
for AWD and in-between positions, the TCCM may
interpret the resistance as:
²the AWD position.
²an invalid fault position.
²a 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:
²a valid in-between position.
²an invalid fault position.
For resistances between the ranges A and B shown
for the fault condition (short) and , T-Case NEU-
TRAL, the TCCM may interpret the resistance as:²the T-Case NEUTRAL position.
²an invalid fault position.
The LED's in the selector assembly are illuminat-
ed/flashed in the following manner to indicate a par-
ticular condition or state.
²A solidly illuminated LED indicates a success-
fully completed shift and the current operating mode
of the transfer case. While a shift has been requested
but not yet completed, the LED for the desired trans-
fer case position is flashed.
²A flashing operating mode LED for the desired
gear indicates that a shift to that position has been
requested, but all of the driver controllable conditions
have not been met. This is in an attempt to notify
the driver that the transmission needs to be put into
NEUTRAL, the vehicle speed is too great, or some
other condition outlined (other than a diagnostic fail-
ure that would prevent this shift) elsewhere (Refer to
8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/TRANSFER CASE CONTROL MODULE -
OPERATION) is not met. Note that this flashing will
continue indefinitely until the conditions are eventu-
ally met, or the selector switch position is changed,
or if diagnostic routines no longer allow the
requested shift.
²If the driver attempts to make a shift into trans-
fer case NEUTRAL, and any of the driver controlla-
ble conditions are not met, the request will be
ignored until all of the conditions are met or until
the NEUTRAL select button is released. Additionally
the neutral lamp will flash, or begin to flash while
the button is depressed and operator controllable
conditions are not being met. All of the LED's except
the Neutral will flash if any of the operator control-
lable conditions for shifting are not met while the
Neutral button is depressed. This9toggle9type of fea-
ture is necessary because the TCCM would interpret
another request immediately after the shift into
transfer case NEUTRAL has completed.
²No LED's illuminated indicate a fault in the
transfer case control system.
21 - 540 TRANSFER CASE - NV244 GENIIDR
SELECTOR SWITCH (Continued)

IDENTIFICATION
A circular ID tag is attached to the rear case of
each transfer case (Fig. 1). 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 out-
put 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 engaged/disengaged
by the mode fork, which operates the mode sleeve
and hub. The sleeve and hub are not equipped with a
synchronizer mechanism for shifting.
DIAGNOSIS AND TESTING - TRANSFER CASE - NV273
DIAGNOSIS CHART
Condition Possible Cause Correction
Transfer case difficult to shift or will
not shift into desired range.1) Transfer case electronically
controlled shift system malfunction.1) Verify proper operation per the
appropriate diagnostic manual.
2) If vehicle was operated for an
extended period in 4HI mode on
dry surface, driveline torque load
may cause difficulty.2) Drive the vehicle in a straight line
and momentarily release the
accelerator. The transfer case can
then be shifted to the desired mode.
3) Insufficient or incorrect lubricant. 3) Drain and refill transfer case with
the correct quantity of MoparTAT F
+4, Automatic Transmission Fluid.
4) Internal transfer case
components binding, worn, or
damaged.4) 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 quantity of MoparTAT F
+4, type 9602, Automatic
Transmission Fluid.
2) Internal transfer case
components binding, worn, or
damaged.2) Repair or replace components as
necessary.
Fig. 1 Transfer Case - Rear View
1 - TRANSFER CASE
2 - IDENTIFICATION TAG
DRTRANSFER CASE - NV273 21 - 543
TRANSFER CASE - NV273 (Continued)

MODE SENSOR
DESCRIPTION
The transfer case mode sensor (Fig. 94) is an elec-
tronic device whose output can be interpreted to indi-
cate 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 CHAN-
NEL STATES for the sensor codes returned to the
TCCM for each transfer case mode sensor position.
The various between gears positions 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
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
Fig. 94 Mode Sensor
1 - MODE SENSOR
DRTRANSFER CASE - NV273 21 - 573

have not been met. This is in an attempt to notify
the driver that the transmission needs to be put into
NEUTRAL, the vehicle speed is too great, or some
other condition outlined (other than a diagnostic fail-
ure that would prevent this shift) elsewhere (Refer to
8 - ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/TRANSFER CASE CONTROL MODULE -
OPERATION) is not met. Note that this flashing will
continue indefinitely until the conditions are eventu-
ally met, or the selector switch position is changed,
or if diagnostic routines no longer allow the
requested shift.
²
If the driver attempts to make a shift into transfer
case NEUTRAL, and any of the driver controllable con-
ditions are not met, the request will be ignored until all
of the conditions are met or until the NEUTRAL select
button is released. Additionally the neutral lamp will
flash, or begin to flash while the button is depressed
and operator controllable conditions are not being met.
All of the LED's except the Neutral will flash if any of
the operator controllable conditions for shifting are not
met while the Neutral button is depressed. This9toggle9
type of feature is necessary because the TCCM would
interpret another request immediately after the shift
into transfer case NEUTRAL has completed.
²No LED's illuminated indicate a fault in the
transfer case control system.
SHIFT MOTOR
DESCRIPTION
The shift motor (Fig. 96) 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 72É 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 transfer case shift sector bi-directionally, as
required, to obtain the transfer case operating mode
indicated by the instrument panel mounted selector
switch.
REMOVAL
NOTE: New shift motor assemblies are shipped in
the 2WD/AWD position. If a new shift motor assem-
bly will be installed, it will be necessary to shift the
transfer case to the 2WD/AWD position 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 sec-
tor shaft orientation are aligned. It may be neces-
sary to manually shift the transfer case if the shift
motor and sector shaft are not aligned.
(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 N´m (12-18
ft.lbs.).
CAUTION: If the original shift motor and mode sen-
sor assembly bolts are reused, be sure to use
MoparTLock & Seal or LoctiteŸ 242 to replenish
the lock patch material originally found on the bolts
(4) Engage the wiring connectors to the shift motor
and mode sensor.
(5) Refill the transfer case as necessary.
(6) Lower vehicle and verify transfer case
operation.
Fig. 96 Shift Motor - Shown Inverted - Typical
1 - SHIFT MOTOR
DRTRANSFER CASE - NV273 21 - 575
SELECTOR SWITCH (Continued)