1998 DODGE RAM 1500 torque

TRANSFER CASE - NV273
TABLE OF CONTENTS
page page
TRANSFER CASE - NV273
DESCRIPTION........................542
OPERATION..........................543
DIAGNOSIS AND TESTING - TRANSFER
CASE - NV273.......................543
REMOVAL............................544
DISASSEMBLY........................544
CLEANING...........................554
INSPECTION.........................554
ASSEMBLY...........................556
INSTALLATION........................568
SPECIFICATIONS
TRANSFER CASE - NV273.............568
SPECIAL TOOLS
TRANSFER CASE NV271/NV273.........569
EXTENSION HOUSING SEAL AND DUST BOOT
REMOVAL............................571
INSTALLATION........................571FLUID
STANDARD PROCEDURE - FLUID DRAIN AND
REFILL............................571
FRONT OUTPUT SHAFT SEAL
REMOVAL............................572
INSTALLATION........................572
MODE SENSOR
DESCRIPTION........................573
OPERATION..........................573
SELECTOR SWITCH
DESCRIPTION........................574
OPERATION..........................574
SHIFT MOTOR
DESCRIPTION........................575
OPERATION..........................575
REMOVAL............................575
INSTALLATION........................575
TRANSFER CASE - NV273
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 NEU-
TRAL position. The low range system provides a gear
reduction ratio for increased low speed torque capa-
bility.
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:
²2WD (2-wheel drive)
²4HI (4-wheel drive)
²4LO (4-wheel drive low range)
²NEUTRAL
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 slip-
pery 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.
21 - 542 TRANSFER CASE - NV273DR

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)

(4) Install 4-5 rear case-to front case bolts (Fig. 81)
to hold rear case in position. Tighten bolts snug but
not to specified torque at this time.
CAUTION: Verify that shift rail, and case alignment
dowels are seated before installing any bolts. Case
could be cracked if shaft rail or dowels are mis-
aligned.
(5) Tighten bolts to 27-34 N´m (20-25 ft. lbs.),
(6) Install rear output bearing inner snap-ring
(Fig. 82) to output shaft.OIL PUMP AND REAR EXTENSION
(1) Install the oil pump (Fig. 83) onto the output
shaft.
(2) Engage the oil pump pick-up tube (Fig. 84) into
the oil pump. Verify that the pick-up tube o-ring is
on the tube and is correctly installed to the oil pump.
Fig. 81 Install Case Half Bolts
1 - FRONT CASE HALF
2 - REAR CASE HALF
3 - BOLTS
Fig. 82 Install Rear Bearing Inner Snap-Ring
1 - OUTPUT SHAFT
2 - REAR CASE HALF
3 - SNAP-RING
Fig. 83 Install Oil Pump
1 - REAR CASE HALF
2 - REAR OUTPUT SHAFT
3 - OIL PUMP
Fig. 84 Engage The Oil Pick-up To Oil Pump
1 - OIL PUMP
2 - OIL PICK-UP TUBE
21 - 566 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)

(7) Install the front companion flange onto the
front output shaft.
(8) Install two bolts 180É apart into the front out-
put shaft companion flange.
(9) Place holder over the bolts and against the
companion flange (Fig. 88).
(10) Install a new front companion flange nut.
Tighten the companion flange nut to 176-271 N´m
(130-200 ft.lbs.).
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 N´m (20-25 ft. lbs.) torque.
(6) Connect the vent hose.
(7) Connect the shift motor and mode sensor wir-
ing connectors. Secure wire harness to clips on trans-
fer case.
(8) Align and connect the propeller shafts.
(9) Fill transfer case with correct fluid. (Refer to
21 - TRANSMISSION/TRANSFER CASE/FLUID -
STANDARD PROCEDURE)
(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 - NV273
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 27-34 20-25 -
Bolt, Case Half 27-34 20-25 -
Support, Sector 27-34 20-25 -
Nuts, Mounting 30-41 20-30 -
Bolts, Shift Motor and
Mode Sensor Assembly16-25 12-18 -
Nut, Companion Flange 176-271 130-200 -
Fig. 88 Install Companion Flange Nut
1 - HOLDER 6719
2 - BOLTS
21 - 568 TRANSFER CASE - NV273DR
TRANSFER CASE - NV273 (Continued)

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)

TIRES/WHEELS
TABLE OF CONTENTS
page page
TIRES/WHEELS
DIAGNOSIS AND TESTING - TIRE AND
WHEEL RUNOUT......................1
STANDARD PROCEDURE
STANDARD PROCEDURE - TIRE ROTATION . 3
STANDARD PROCEDURE - MATCH
MOUNTING...........................3
STANDARD PROCEDURE - TIRE AND
WHEEL BALANCE......................4
TIRES
DESCRIPTION
DESCRIPTION - SPARE TIRE /
TEMPORARY.........................6
DESCRIPTION - TIRES..................6
DESCRIPTION - RADIAL ± PLY TIRES......6
DESCRIPTION - TIRE PRESSURE FOR
HIGH SPEEDS.........................7
DESCRIPTION - REPLACEMENT TIRES.....7
DESCRIPTION - TIRE INFLATION
PRESSURES..........................7
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - PRESSURE
GAUGES.............................7
DIAGNOSIS AND TESTING - TIRE NOISE
OR VIBRATION........................7
DIAGNOSIS AND TESTING - TREAD WEAR
INDICATORS..........................8
DIAGNOSIS AND TESTING - TIRE WEAR
PATTERNS...........................8
DIAGNOSIS AND TESTING - TIRE/VEHICLE
LEAD................................8STANDARD PROCEDURE - REPAIRING
LEAKS..............................10
SPECIFICATIONS
TIRE REVOLUTIONS PER MILE..........10
WHEELS
DESCRIPTION.........................11
OPERATION...........................11
DIAGNOSIS AND TESTING
WHEEL INSPECTION..................11
STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL
REPLACEMENT.......................12
STANDARD PROCEDURE - DUAL REAR
WHEEL INSTALLATION.................12
SPECIFICATIONS
TORQUE CHART......................13
STUDS
REMOVAL.............................14
INSTALLATION.........................14
WHEEL COVER
REMOVAL.............................14
INSTALLATION
INSTALLATION - REAR.................14
INSTALLATION - FRONT................14
SPARE TIRE
DESCRIPTION
DESCRIPTION - SPARE / TEMPORARY
TIRE...............................15
DESCRIPTION - FULL SIZE, SPARE WHEEL
WITH MATCHING TIRE.................15
TIRES/WHEELS
DIAGNOSIS AND TESTING - TIRE AND WHEEL
RUNOUT
Radial runout is the difference between the high
and low points on the tire or wheel (Fig. 1).
Lateral runout is thewobbleof the tire or wheel.
Radial runout of more than 1.5 mm (.060 inch)
measured at the center line of the tread may cause
the vehicle to shake.Lateral runout of more than 2.0 mm (.080 inch)
measured near the shoulder of the tire may cause the
vehicle to shake.
Sometimes radial runout can be reduced. Relocate
the wheel and tire assembly on the mounting studs
(See Method 1). If this does not reduce runout to an
acceptable level, the tire can be rotated on the wheel.
(See Method 2).
DRTIRES/WHEELS 22 - 1

METHOD 1 (RELOCATE WHEEL ON HUB)
(1) Drive vehicle a short distance to eliminate tire
flat spotting from a parked position.
(2) Check wheel bearings and adjust if adjustable
or replace if necessary.
(3) Check the wheel mounting surface.
(4) Relocate wheel on the mounting, two studs
over from the original position.
(5) Tighten wheel nuts until all are properly
torqued, to eliminate brake distortion.
(6) Check radial runout. If still excessive, mark
tire sidewall, wheel, and stud at point of maximum
runout and proceed to Method 2.
METHOD 2 (RELOCATE TIRE ON WHEEL)
NOTE: Rotating the tire on wheel is particularly
effective when there is runout in both tire and
wheel.
(1) Remove tire from wheel and mount wheel on
service dynamic balance machine.
(2) Check wheel radial runout (Fig. 2) and lateral
runout (Fig. 3).
²STEEL WHEELS: Radial runout 0.031 in., Lat-
eral runout 0.031 in. (maximum)
²ALUMINUM WHEELS: Radial runout 0.020 in.,
Lateral runout 0.025 in. (maximum)
(3) If point of greatest wheel lateral runout is near
original chalk mark, remount tire 180 degrees.
Recheck runout, Refer to match mounting procedure.
Fig. 1 Checking Tire/Wheel/Hub Runout
1 - RADIAL RUNOUT
2 - LATERAL RUNOUT
Fig. 2 Radial Runout
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
Fig. 3 Lateral Runout
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
22 - 2 TIRES/WHEELSDR
TIRES/WHEELS (Continued)

STANDARD PROCEDURE - REPAIRING LEAKS
For proper repairing, a radial tire must be removed
from the wheel. Repairs should only be made if the
defect, or puncture, is in the tread area (Fig. 17). The
tire should be replaced if the puncture is located in
the sidewall.
Deflate tire completely before removing the tire
from the wheel. Use lubrication such as a mild soap
solution when dismounting or mounting tire. Use
tools free of burrs or sharp edges which could dam-
age the tire or wheel rim.
Before mounting tire on wheel, make sure all rust
is removed from the rim bead and repaint if neces-
sary.
Install wheel on vehicle, and tighten to proper
torque specification, (Refer to 22 - TIRES/WHEELS/
WHEELS - SPECIFICATIONS).
SPECIFICATIONS
TIRE REVOLUTIONS PER MILE
TIRE SIZE SUPPLIER REVOLUTIONS PER MILE
P245/70R17
WRANGLER SRAGOODYEART685
LT245/70R17
LTX A/SMICHELINT675
LT265/70R17
LTX A/SMICHELINT657
LT245/70R17
RUGGED TRAIL T/ABF GOODRICHT684
LT265/70R17
RUGGED TRAIL T/ABF GOODRICHT658
P265/70R17
WRANGLER SR/AGOODYEART657
P265/70R17
WRANGLER GS/AGOODYEART661
LT275/70R17
WRANGLER AT/SGOODYEART649
LT275/70R17
TTLGOODYEART649
P275/55R20
EAGLE LSGOODYEART655
P275/60R20
WRANGLER HPGOODYEART636
LT235/80R17E
WRANGLER SRAGOODYEART649
LT235/80R17E
WRANGLER GSAGOODYEART649
Fig. 17 TIRE REPAIR AREA
1 - TIRE REPAIR AREA
22 - 10 TIRES/WHEELSDR
TIRES (Continued)