Dodge Ram Truck 1500-2500-3500. Manual — part 1893
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 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/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 sector shaft orientation are aligned. It may be necessary 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 sensor assembly bolts are reused, be sure to use Mopar
T
Lock & Seal or Loctite™ 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.
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TRANSFER CASE - NV244 GENII - SERVICE INFORMATION
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TRANSFER CASE - NV273 - SERVICE INFORMATION
TABLE OF CONTENTS
page
page
TRANSFER CASE - NV273 - SERVICE
INFORMATION
DESCRIPTION
. . . . . . . . . . . . . . . . . . . . . . . 1505
. . . . . . . . . . . . . . . . . . . . . . . . . 1506
DIAGNOSIS AND TESTING - TRANSFER
. . . . . . . . . . . . . . . . . . . . . . 1506
. . . . . . . . . . . . . . . . . . . . . . . . . . . 1507
. . . . . . . . . . . . . . . . . . . . . . . 1507
. . . . . . . . . . . . . . . . . . . . . . . . . . 1524
. . . . . . . . . . . . . . . . . . . . . . . . . 1524
. . . . . . . . . . . . . . . . . . . . . . . . . . 1528
. . . . . . . . . . . . . . . . . . . . . . . 1548
BOOT-EXTENSION HOUSING SEAL AND DUST
. . . . . . . . . . . . . . . . . . . . . . . . . . . 1552
. . . . . . . . . . . . . . . . . . . . . . . 1552
FLUID
STANDARD PROCEDURE - FLUID DRAIN AND
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1553
SEAL-FRONT OUTPUT SHAFT
. . . . . . . . . . . . . . . . . . . . . . . . . . . 1553
. . . . . . . . . . . . . . . . . . . . . . . 1554
SENSOR-MODE
. . . . . . . . . . . . . . . . . . . . . . . 1554
. . . . . . . . . . . . . . . . . . . . . . . . . 1554
SWITCH-SELECTOR
. . . . . . . . . . . . . . . . . . . . . . . 1555
. . . . . . . . . . . . . . . . . . . . . . . . . 1556
MOTOR-SHIFT
. . . . . . . . . . . . . . . . . . . . . . . 1557
. . . . . . . . . . . . . . . . . . . . . . . . . 1557
. . . . . . . . . . . . . . . . . . . . . . . . . . . 1557
. . . . . . . . . . . . . . . . . . . . . . . 1557
TRANSFER CASE - NV273 - SERVICE INFORMATION
DESCRIPTION
The NV273 is an electronically controlled part-time transfer case with a low range gear reduction system. The
NV273 has three operating ranges plus a NEUTRAL position. The low range system provides a gear reduction ratio
for increased low speed torque capability.
The geartrain is mounted in two aluminum case halves attached with bolts. The mainshaft front and rear bearings
are mounted in aluminum case halves.
OPERATING RANGES
Transfer case operating ranges are:
•
2WD (2-wheel drive)
•
4HI (4-wheel drive)
•
4LO (4-wheel drive low range)
•
NEUTRAL
The 2WD range is for use on any road surface at any time.
The 4HI and 4LO ranges are for off road use only. They are not for use on hard surface roads. The only exception
being when the road surface is wet or slippery or covered by ice and snow.
The low range reduction gear system is operative in 4LO range only. This range is for extra pulling power in off road
situations. Low range reduction ratio is 2.72:1.
SHIFT MECHANISM
Operating ranges are selected with a dash mounted shift selector switch. The shift selector switch provides a input
to the Transfer Case Control Module (TCCM) to indicate the driver’s desire to change operating ranges. The TCCM
uses this input, along with input from the transfer case mounted mode sensor and information from the vehicle’s
bus, to determine if a shift is permitted. If the TCCM decides the shift is permitted, the TCCM controls the shift
motor, mounted to the exterior of the transfer case, to perform the shift.
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TRANSFER CASE - NV273 - SERVICE INFORMATION
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IDENTIFICATION
A circular ID tag (2)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 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 Mopar
T
ATF
+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 Mopar
T
ATF
+4, type 9602, Automatic
Transmission Fluid.
2) Internal transfer case
components binding, worn, or
damaged.
2) Repair or replace components as
necessary.
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TRANSFER CASE - NV273 - SERVICE INFORMATION
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Condition
Possible Cause
Correction
Transfer case noisy while in, or
jumps out of, 4LO mode.
1) Transfer case not completely
engaged in 4LO position.
1) While rolling 2-3 MPH and the
transmission in NEUTRAL, or clutch
depressed on vehicles equipped
with a manual transmission, shift
transfer case to the 2WD 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.
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.
Abnormal tire wear.
1) Extended operation in 4HI mode
on dry surfaces,
1) Operate vehicle in 2WD mode on
dry surfaces.
REMOVAL
1. Shift transfer case into 2WD.
2. Raise vehicle.
3. Drain transfer case lubricant.
4. Mark front and rear propeller shafts for alignment
reference.
5. Support transmission with jack stand.
6. Remove the transfer case skid plate, if equipped.
7. Disconnect front and rear propeller shafts at trans-
fer case.
8. Disconnect transfer case shift motor and mode
sensor wire connectors (3).
9. Disconnect transfer case vent hose.
10. Support transfer case with transmission jack.
11. Secure transfer case to jack with chains.
12. Remove nuts attaching transfer case (2) to transmission (1).
13. Pull transfer case and jack rearward to disengage transfer case.
14. Remove transfer case from under vehicle.
DISASSEMBLY
Position transfer case in a shallow drain pan. Remove drain plug and drain any remaining lubricant remaining in
case.
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