1998 DODGE RAM 1500 width

(8) Install front sprocket retaining ring (Fig. 77).
(9) Install rear sprocket retaining ring (Fig. 78).(10) Insert magnet in front case pocket (Fig. 79).
REAR CASE
(1) Install the oil pick-up tube and screen into the
rear case half.
(2) Apply bead of MopartGasket Maker, or equiv-
alent, to mating surface of front case. Keep sealer
bead width to maximum of 3/16 inch. Do not use
excessive amount of sealer as excess will be displaced
into case interior.
(3) Align mainshaft with the rear output shaft
bearing and align shift rail with bore in rear case.
Then install rear case (Fig. 80). Verify that the case
alignment dowels correctly seat into their mating
recesses.
Fig. 77 Install Front Output Shaft Sprocket
Retaining Ring
1 - FRONT OUTPUT SHAFT
2 - DRIVE SPROCKET
3 - RETAINING RING
Fig. 78 Install Rear Output Shaft Sprocket Retaining
Ring
1 - REAR OUTPUT SHAFT
2 - DRIVE SPROCKET
3 - RETAINING RING
Fig. 79 Case Magnet Installation
1 - MAGNET
2 - CASE POCKET
Fig. 80 Install Rear Case Half
1 - FRONT CASE HALF
2 - REAR CASE HALF
DRTRANSFER CASE - NV273 21 - 565
TRANSFER CASE - NV273 (Continued)

(3) Apply bead of MopartGasket Maker, or equiv-
alent, 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.
(4) Install extension housing (Fig. 85) onto the
rear case half.
(5) Install rear extension bolts (Fig. 86). Tighten
the bolts to 27-34 N´m (20-25 ft.lbs.).(6) Install the extension housing dust boot and
seal assembly with Installer 9037 and Handle C-4171
(Fig. 87).
Fig. 85 Install Extension Housing
1 - REAR CASE HALF
2 - EXTENSION HOUSING
Fig. 86 Install Extension Housing Bolts
1 - EXTENSION HOUSING
2 - BOLTS
Fig. 87 Install Extension Housing Seal
1 - EXTENSION HOUSING
2 - HANDLE C-4171
3 - INSTALLER 9037
DRTRANSFER CASE - NV273 21 - 567
TRANSFER CASE - NV273 (Continued)

WHEELS
DESCRIPTION
Original equipment wheels are designed for the
specified Maximum Vehicle Capacity.
All models use steel or aluminum drop center
wheels.
Aluminum wheels require special balance weights
and alignment equipment.
(1) On vehicles equipped with dual rear wheels,
The rim is an eight stud hole pattern wheel. The
wheels have a flat mounting surface (Fig. 18). The
slots in the wheel must be aligned to provide access
to the valve stem (Fig. 19).
OPERATION
The wheel (Fig. 20) has raised sections between
the rim flanges and the rim well. Initial inflation of
the tire forces the bead over these raised sections. In
case of tire failure, the raised sections hold the tire
in position on the wheel until the vehicle can be
brought to a safe stop.
DIAGNOSIS AND TESTING
WHEEL INSPECTION
Inspect wheels for:
²Excessive run out
²Dents or cracks
²Damaged wheel lug nut holes
²Air Leaks from any area or surface of the rim
NOTE: Do not attempt to repair a wheel by hammer-
ing, heating or welding.
If a wheel is damaged an original equipment
replacement wheel should be used. When obtaining
replacement wheels, they should be equivalent in
load carrying capacity. The diameter, width, offset,
pilot hole and bolt circle of the wheel should be the
same as the original wheel.
WARNING: FAILURE TO USE EQUIVALENT
REPLACEMENT WHEELS MAY ADVERSELY
AFFECT THE SAFETY AND HANDLING OF THE
VEHICLE. USED WHEELS ARE NOT RECOM-
MENDED. THE SERVICE HISTORY OF THE WHEEL
MAY HAVE INCLUDED SEVERE TREATMENT OR
VERY HIGH MILEAGE. THE RIM COULD FAIL WITH-
OUT WARNING.
Fig. 18 FLAT FACE WHEEL
1 - FLAT FACE
2 - VALVE STEM
Fig. 19 DUAL REAR WHEELS
1 - WINDOW OPENINGS (5)
2 - INBOARD VALVE STEM
3 - OUTBOARD VALVE STEM
Fig. 20 Safety Rim
1 - FLANGE
2 - RIDGE
3 - WELL
DRTIRES/WHEELS 22 - 11

STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL
REPLACEMENT
The wheel studs and nuts are designed for specific
applications. They must be replaced with equivalent
parts. Do not use replacement parts of lesser quality
or a substitute design. All aluminum and some steel
wheels have wheel stud nuts which feature an
enlarged nose. This enlarged nose is necessary to
ensure proper retention of the aluminum wheels.
NOTE: Do not use chrome plated lug nuts with
chrome plated wheels.
Before installing the wheel, be sure to remove any
build up of corrosion on the wheel mounting surfaces.
Ensure wheels are installed with good metal-to-metal
contact. Improper installation could cause loosening
of wheel nuts (Fig. 21). This could affect the safety
and handling of your vehicle.
To install the wheel, first position it properly on
the mounting surface (Fig. 21). All wheel nuts should
then be tightened just snug. Gradually tighten them
in sequence to the proper torque specification, (Fig.
22) (Fig. 23).Never use oil or grease on studs or
nuts.
Wheels must be replaced if they have:
²Excessive runout
²Bent or dented
²Leak air through welds
²Have damaged bolt holes
Wheel repairs employing hammering, heating, or
welding are not allowed.Original equipment wheels are available through
your dealer. Replacement wheels from any other
source should be equivalent in:
²Load carrying capacity
²Diameter
²Width
²Offset
²Mounting configuration
Failure to use equivalent replacement wheels may
affect the safety and handling of your vehicle.
Replacement withusedwheels is not recommended.
Their service history may have included severe treat-
ment.
STANDARD PROCEDURE - DUAL REAR WHEEL
INSTALLATION
Dual rear wheels use a special heavy duty lug nut
wrench. It is recommended to remove and install
dual rear wheels only when the proper wrench is
available. The wrench is also use to remove wheel
Fig. 21 WHEEL INSTALLATION 8-LUG SHOWN
1 - CENTER CAP
2 - LUG NUT
3 - TIRE/WHEEL ASSEMBLY
4 - WHEEL STUDS
Fig. 22 8-LUG TIGHTENING PATTERN
Fig. 23 TYPICAL 6 - LUG NUT TIGHTENING
PATTERN
22 - 12 TIRES/WHEELSDR
WHEELS (Continued)

should be stripped of paint and freed from wax and
oil. Scuff surfaces around repair area with 360 grit
wet/dry sandpaper, or equivalent, to assure adhesion
of repair materials.
PATCHING PANELS
An panel that has extensive puncture type damage
can be repaired by cutting out the damaged material
(Fig. 7). Use a suitable reciprocating saw or cut off
wheel to remove the section of the panel that is dam-
aged. The piece cut out can be used as a template to
shape the new patch. It is not necessary to have
access to the back of the panel to install a patch.
Bevel edges of cutout at 20 degrees to expose a larger
bonding area on the outer side. This will allow for an
increased reinforcement areas.
PANEL PATCH FABRICATIONS
A patch can be fabricated from any rigid fiberglass
panel that has comparable contour with the repair
area. Lift gates and fenders can be used to supply
patch material. If existing material is not available
or compatible, a patch can be constructed with adhe-
sive and reinforcement mesh (dry wall tape). Perform
the following operation if required:
(1) Cover waxed paper or plastic with adhesive
backed nylon mesh (dry wall tape) larger than the
patch required (Fig. 8).(2) Tape waxed paper or plastic sheet with mesh to
a surface that has a compatible contour to the repair
area.
(3) Apply a liberal coat of adhesive over the rein-
forcement mesh (Fig. 8). If necessary apply a second
or third coat of adhesive and mesh after first coat
has cured. The thickness of the patch should be the
same as the repair area.
(4) After patch has cured, peel waxed paper or
plastic from the back of the patch.
(5) If desired, a thin film coat of adhesive can be
applied to the back of the patch to cover mesh for
added strength.
PANEL PATCH INSTALLATION
(1) Make a paper or cardboard pattern the size
and shape of the cutout hole in the panel.
(2) Trim 3 mm (0.125 in.) from edges of pattern so
patch will have a gap between connecting surfaces.
(3) Using the pattern as a guide, cut the patch to
size.
(4) Cut scrap pieces of patch material into 50 mm
(2 in.) squares to use as patch supports to sustain
the patch in the cutout.
(5) Drill 4 mm (0.160 in.) holes 13 mm (0.5 in.) in
from edge of cutout hole (Fig. 7).
(6) Drill 4 mm (0.160 in.) holes 13 mm (0.5 in.)
away from edge of patch across from holes drilled
around cutout.
Fig. 7 DAMAGED PANEL CUTOUT AND PATCH
1 - CUTOUT
2 - DAMAGED BODY PANEL
3-4MM(0.160 IN.) HOLES
4 - PATCH CUT TO SIZE
Fig. 8 FABRICATED PANEL
1 - STRUCTURAL ADHESIVE
2 - FIBERGLASS CLOTH OR FIBERGLASS MESH TAPE
3 - WIDTH OF V-GROOVE
4 - WAXED PAPER
23 - 8 BODYDR
BODY (Continued)

DESCRIPTION - MONITORED SYSTEMS
There are new electronic circuit monitors that
check fuel, emission, engine and ignition perfor-
mance. These monitors use information from various
sensor circuits to indicate the overall operation of the
fuel, engine, ignition and emission systems and thus
the emissions performance of the vehicle.
The fuel, engine, ignition and emission systems
monitors do not indicate a specific component prob-
lem. They do indicate that there is an implied prob-
lem within one of the systems and that a specific
problem must be diagnosed.
If any of these monitors detect a problem affecting
vehicle emissions, the Malfunction Indicator Lamp
(MIL) will be illuminated. These monitors generate
Diagnostic Trouble Codes that can be displayed with
the MIL or a scan tool.
The following is a list of the system monitors:
²Misfire Monitor
²Fuel System Monitor
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
²Leak Detection Pump Monitor (if equipped)
All these system monitors require two consecutive
trips with the malfunction present to set a fault.
Refer to the appropriate Powertrain Diagnos-
tics Procedures manual for diagnostic proce-
dures.
The following is an operation and description of
each system monitor :
OXYGEN SENSOR (O2S) MONITOR
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperature 300É to 350ÉC (572É to 662ÉF), the
sensor generates a voltage that is inversely propor-
tional to the amount of oxygen in the exhaust. The
information obtained by the sensor is used to calcu-
late the fuel injector pulse width. This maintains a
14.7 to 1 Air Fuel (A/F) ratio. At this mixture ratio,
the catalyst works best to remove hydrocarbons (HC),
carbon monoxide (CO) and nitrogen oxide (NOx) from
the exhaust.
The O2S is also the main sensing element for the
Catalyst and Fuel Monitors.
The O2S can fail in any or all of the following
manners:
²slow response rate
²reduced output voltage
²dynamic shift
²shorted or open circuits
Response rate is the time required for the sensor to
switch from lean to rich once it is exposed to a richerthan optimum A/F mixture or vice versa. As the sen-
sor starts malfunctioning, it could take longer to
detect the changes in the oxygen content of the
exhaust gas.
The output voltage of the O2S ranges from 0 to 1
volt. A good sensor can easily generate any output
voltage in this range as it is exposed to different con-
centrations of oxygen. To detect a shift in the A/F
mixture (lean or rich), the output voltage has to
change beyond a threshold value. A malfunctioning
sensor could have difficulty changing beyond the
threshold value.
OXYGEN SENSOR HEATER MONITOR
If there is an oxygen sensor (O2S) shorted to volt-
age DTC, as well as a O2S heater DTC, the O2S
fault MUST be repaired first. Before checking the
O2S fault, verify that the heater circuit is operating
correctly.
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperature 300É to 350ÉC (572 É to 662ÉF), the
sensor generates a voltage that is inversely propor-
tional to the amount of oxygen in the exhaust. The
information obtained by the sensor is used to calcu-
late the fuel injector pulse width. This maintains a
14.7 to 1 Air Fuel (A/F) ratio. At this mixture ratio,
the catalyst works best to remove hydrocarbons (HC),
carbon monoxide (CO) and nitrogen oxide (NOx) from
the exhaust.
The voltage readings taken from the O2S sensor
are very temperature sensitive. The readings are not
accurate below 300ÉC. Heating of the O2S sensor is
done to allow the engine controller to shift to closed
loop control as soon as possible. The heating element
used to heat the O2S sensor must be tested to ensure
that it is heating the sensor properly.
The O2S sensor circuit is monitored for a drop in
voltage. The sensor output is used to test the heater
by isolating the effect of the heater element on the
O2S sensor output voltage from the other effects.
LEAK DETECTION PUMP MONITOR (IF EQUIPPED)
The leak detection assembly incorporates two pri-
mary functions: it must detect a leak in the evapora-
tive system and seal the evaporative system so the
leak detection test can be run.
The primary components within the assembly are:
A three port solenoid that activates both of the func-
tions listed above; a pump which contains a switch,
two check valves and a spring/diaphragm, a canister
vent valve (CVV) seal which contains a spring loaded
vent seal valve.
25 - 2 EMISSIONS CONTROLDR
EMISSIONS CONTROL (Continued)

Immediately after a cold start, between predeter-
mined temperature thresholds limits, the three port
solenoid is briefly energized. This initializes the
pump by drawing air into the pump cavity and also
closes the vent seal. During non test conditions the
vent seal is held open by the pump diaphragm
assembly which pushes it open at the full travel posi-
tion. The vent seal will remain closed while the
pump is cycling due to the reed switch triggering of
the three port solenoid that prevents the diaphragm
assembly from reaching full travel. After the brief
initialization period, the solenoid is de-energized
allowing atmospheric pressure to enter the pump
cavity, thus permitting the spring to drive the dia-
phragm which forces air out of the pump cavity and
into the vent system. When the solenoid is energized
and de energized, the cycle is repeated creating flow
in typical diaphragm pump fashion. The pump is con-
trolled in 2 modes:
Pump Mode: The pump is cycled at a fixed rate to
achieve a rapid pressure build in order to shorten the
overall test length.
Test Mode: The solenoid is energized with a fixed
duration pulse. Subsequent fixed pulses occur when
the diaphragm reaches the Switch closure point.
The spring in the pump is set so that the system
will achieve an equalized pressure of about 7.5º H20.
The cycle rate of pump strokes is quite rapid as the
system begins to pump up to this pressure. As the
pressure increases, the cycle rate starts to drop off. If
there is no leak in the system, the pump would even-
tually stop pumping at the equalized pressure. If
there is a leak, it will continue to pump at a rate rep-
resentative of the flow characteristic of the size of the
leak. From this information we can determine if the
leak is larger than the required detection limit (cur-
rently set at .040º orifice by CARB). If a leak is
revealed during the leak test portion of the test, the
test is terminated at the end of the test mode and no
further system checks will be performed.
After passing the leak detection phase of the test,
system pressure is maintained by turning on the
LDP's solenoid until the purge system is activated.
Purge activation in effect creates a leak. The cycle
rate is again interrogated and when it increases due
to the flow through the purge system, the leak check
portion of the diagnostic is complete.
The canister vent valve will unseal the system
after completion of the test sequence as the pump
diaphragm assembly moves to the full travel position.
Evaporative system functionality will be verified by
using the stricter evap purge flow monitor. At an
appropriate warm idle the LDP will be energized to
seal the canister vent. The purge flow will be clocked
up from some small value in an attempt to see a
shift in the 02 control system. If fuel vapor, indicatedby a shift in the 02 control, is present the test is
passed. If not, it is assumed that the purge system is
not functioning in some respect. The LDP is again
turned off and the test is ended.
MISFIRE MONITOR
Excessive engine misfire results in increased cata-
lyst temperature and causes an increase in HC emis-
sions. Severe misfires could cause catalyst damage.
To prevent catalytic convertor damage, the PCM
monitors engine misfire.
The Powertrain Control Module (PCM) monitors
for misfire during most engine operating conditions
(positive torque) by looking at changes in the crank-
shaft speed. If a misfire occurs the speed of the
crankshaft will vary more than normal.
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide. The catalyst works best
when the Air Fuel (A/F) ratio is at or near the opti-
mum of 14.7 to 1.
The PCM is programmed to maintain the optimum
air/fuel ratio of 14.7 to 1. This is done by making
short term corrections in the fuel injector pulse width
based on the O2S sensor output. The programmed
memory acts as a self calibration tool that the engine
controller uses to compensate for variations in engine
specifications, sensor tolerances and engine fatigue
over the life span of the engine. By monitoring the
actual fuel-air ratio with the O2S sensor (short term)
and multiplying that with the program long-term
(adaptive) memory and comparing that to the limit,
it can be determined whether it will pass an emis-
sions test. If a malfunction occurs such that the PCM
cannot maintain the optimum A/F ratio, then the
MIL will be illuminated.
CATALYST MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide.
Normal vehicle miles or engine misfire can cause a
catalyst to decay. This can increase vehicle emissions
and deteriorate engine performance, driveability and
fuel economy.
The catalyst monitor uses dual oxygen sensors
(O2S's) to monitor the efficiency of the converter. The
dual O2S's sensor strategy is based on the fact that
as a catalyst deteriorates, its oxygen storage capacity
and its efficiency are both reduced. By monitoring
the oxygen storage capacity of a catalyst, its effi-
ciency can be indirectly calculated. The upstream
DREMISSIONS CONTROL 25 - 3
EMISSIONS CONTROL (Continued)

CCV HOSE
DESCRIPTION - 8.0L V-10
The 8.0L V-10 engine is equipped with a Crankcase
Ventilation (CCV) system. The CCV system performs
the same function as a conventional PCV system, but
does not use a vacuum controlled valve (PCV valve).
A molded vacuum tube connects manifold vacuum
to the top of the right cylinder head (valve) cover.
The vacuum tube connects to a fixed orifice fitting
(Fig. 2) of a calibrated size 2.6 mm (0.10 inches).
OPERATION - 8.0L V-10
A molded vacuum tube connects manifold vacuum
to the top of the right cylinder head (valve) cover.
The vacuum tube connects to a fixed orifice fitting
(Fig. 2) of a calibrated size 2.6 mm (0.10 inches). The
fitting meters the amount of crankcase vapors drawn
out of the engine.The fixed orifice fitting is grey
in color.A similar fitting (but does not contain a
fixed orifice) is used on the left cylinder head (valve)
cover. This fitting is black in color. Do not inter-
change these two fittings.
When the engine is operating, fresh air enters the
engine and mixes with crankcase vapors. Manifold
vacuum draws the vapor/air mixture through the
fixed orifice and into the intake manifold. The vapors
are then consumed during engine combustion.
EVAP/PURGE SOLENOID
DESCRIPTION
The duty cycle EVAP canister purge solenoid is
located in the engine compartment. It is attached to
the side of the Power Distribution Center (PDC).
OPERATION
The Powertrain Control Module (PCM) operates
the solenoid.
During the cold start warm-up period and the hot
start time delay, the PCM does not energize the sole-
noid. When de-energized, no vapors are purged. The
PCM de-energizes the solenoid during open loop oper-
ation.
The engine enters closed loop operation after it
reaches a specified temperature and the time delay
ends. During closed loop operation, the PCM ener-
gizes and de-energizes the solenoid 5 or 10 times per
second, depending upon operating conditions. The
PCM varies the vapor flow rate by changing solenoid
pulse width. Pulse width is the amount of time the
solenoid energizes. The PCM adjusts solenoid pulse
width based on engine operating condition.
REMOVAL
The duty cycle EVAP canister purge solenoid is
located in the engine compartment. It is attached to
the side of the Power Distribution Center (PDC) (Fig.
3).
(1) Disconnect electrical wiring connector at sole-
noid.
(2) Disconnect vacuum harness at solenoid (Fig. 3).
(3) Remove solenoid from mounting bracket.
INSTALLATION
(1) Install solenoid assembly to mounting bracket.
(2) Connect vacuum harness.
(3) Connect electrical connector.
Fig. 2 FIXED ORIFICE FITTING - 8.0L V-10 ENGINE -
TYPICAL
1 - VACUUM TUBE
2 - FIXED ORIFICE FITTING
3 - COIL PACKS
4 - ORIFICE FITTING HOSE CONNECTIONS
25 - 12 EVAPORATIVE EMISSIONSDR