1998 DODGE RAM 1500 air condition

(8) Connect battery cables to both batteries.
(9) Start engine and check for leaks.
INLET AIR TEMPERATURE
SENSOR/PRESSURE SENSOR
DESCRIPTION
The combination, dual function Inlet Air Tempera-
ture/Pressure Sensor is located on the air cleaner (fil-
ter) cover.
OPERATION
The Inlet Air Temperature/Pressure Sensor is a
combination dual-function sensor. The sensor element
extends into the intake air stream at the top of the
air filter housing. Ambient air temperature as well as
barometric pressure is monitored by this sensor. The
Engine Control Module (ECM) monitors signals from
this sensor.
REMOVAL
The Inlet Air Temperature/Pressure Sensor is
located on the air cleaner cover (Fig. 23).
(1) Disconnect electrical connector at sensor (Fig.
24).
(2) Remove two Torx-type mounting screws.
(3) Remove sensor from air cleaner cover.
(4) Check condition of sensor o-ring (Fig. 25).
INSTALLATION
(1) Check condition of sensor o-ring.
(2) Position sensor into top of air cleaner cover
with a slight twisting action.
(3) Install 2 mounting screws.
(4) Install electrical connector.
Fig. 22 FUEL INJECTOR RAIL
1 - FUEL RAIL MOUNTING BOLTS (3)
2 - INSULATED CLAMPS
3 - FUEL INJECTOR RAIL
Fig. 23 IAT/PRESSURE SENSOR LOCATION - 5.9L
DIESEL
1 - CLIPS
2 - FILTER COVER
3 - FILTER MINDERŸ
4 - INLET AIR TEMPERATURE/ PRESSURE SENSOR
5 - FILTER HOUSING
DRFUEL INJECTION - DIESEL 14 - 79
FUEL INJECTOR RAIL (Continued)

INTAKE AIR HEATER RELAY
DESCRIPTION
The 2 intake manifold air heater relays are located
in the engine compartment. They are attached to a
common bracket. This bracket is attached to the
right battery tray (Fig. 29).
OPERATION
The Engine Control Module (ECM) operates the 2
heating elements through the 2 intake manifold air
heater relays.
Refer to Powertrain Diagnostic Procedures for an
electrical operation and complete description of the
intake heaters, including pre-heat and post-heat
cycles.
REMOVAL
The 2 intake manifold air heater relays are located
in the engine compartment. They are attached to a
common bracket. This bracket is attached to the
right battery tray (Fig. 29).
The mounting bracket and both relays are replaced
as an assembly.
(1) Disconnect both negative battery cables at both
batteries.
(2) Disconnect four relay trigger wires at both
relays. Note position of wiring before removing.
(3) Lift four rubber shields from all 4 cables.(4) Remove four nuts at cable connectors. Note
position of wiring before removing.
(5) Remove relay mounting bracket bolts and
remove relay assembly.
INSTALLATION
(1) Install relay assembly to battery tray. Tighten
mounting bolts to 4.5 N´m (40 in. lbs.) torque.
(2) Connect eight electrical connectors to relays.
(3) Connect battery cables to both batteries.
INTAKE AIR TEMPERATURE
SENSOR/MAP SENSOR
DESCRIPTION
The combination, dual function Intake Manifold
Air Temperature Sensor/MAP Sensor is installed into
the top of the intake manifold.
OPERATION
The combination, dual function Intake Manifold
Air Temperature Sensor/MAP Sensor is installed into
the top of the intake manifold with the sensor ele-
ment extending into the air stream.
The IAT portion of the sensor provides an input
voltage to the Engine Control Module (ECM) indicat-
ing intake manifold air temperature. The MAP por-
tion of the sensor provides an input voltage to the
ECM indicating turbocharger boost pressure.
REMOVAL
The combination, dual function Intake Manifold
Air Temperature Sensor/MAP (IAT/MAP) sensor is
installed into the top of the intake manifold (Fig. 30).
(1) Clean area around sensor.
(2) Disconnect electrical connector from IAT/MAP
sensor.
(3) Remove two T-15 Torx headed screws.
(4) Remove sensor from intake manifold.
(5) Check condition of sensor o-ring (Fig. 31).
INSTALLATION
(1) Check condition of sensor o-ring.
(2) Lubricate sensor o-ring with clean engine oil.
(3) Clean sensor mounting area at intake mani-
fold.
(4) Position sensor into intake manifold.
(5) Install and tighten 2 sensor mounting screws
to 1 N´m (9 in. lbs.) torque.
(6) Connect electrical connector to sensor.
Fig. 29 INTAKE MANIFOLD AIR HEATER RELAYS
1 - BATTERY
2 - CABLES TO INTAKE HEATERS
3 - RELAY TRIGGER WIRES
4 - INTAKE AIR HEATER RELAYS (2)
14 - 82 FUEL INJECTION - DIESELDR

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - POWER STEERING
SYSTEM
There is some noise in all power steering systems. One of the most common is a hissing sound evident at a
standstill parking. Or when the steering wheel is at the end of it's travel. Hiss is a high frequency noise similar
to that of a water tap being closed slowly. The noise is present in all valves that have a high velocity fluid passing
through an orifice. There is no relationship between this noise and steering performance.
STEERING NOISE
CONDITION POSSIBLE CAUSES CORRECTION
OBJECTIONAL HISS OR
WHISTLE1. Steering intermediate shaft to dash panel
seal.1. Check and repair seal at dash
panel.
2. Noisy valve in power steering gear. 2. Replace steering gear.
RATTLE OR CLUNK 1. Gear mounting bolts loose. 1. Tighten bolts to specification.
2. Loose or damaged suspension
components.2. Inspect and repair suspension.
3. Internal gear noise. 3. Replace steering gear.
4. Pressure hose in contact with other
components.4. Reposition hose.
5. Loose or damaged intermediate shaft or
column.5. Inspect and repair or replace.
CHIRP OR SQUEAL 1. Loose belt. 1. Adjust or replace.
WHINE OR GROWL 1. Low fluid level. 1. Fill to proper level.
2. Pressure hose in contact with other
components.2. Reposition hose.
3. Internal pump noise. 3. Replace pump.
4. Air in fluid 4. Check for lekas, Evacuate air
from P/S system.
SUCKING AIR SOUND 1. Loose return line clamp. 1. Replace clamp.
2. O-ring missing or damaged on hose
fitting.2. Replace o-ring.
3. Low fluid level. 3. Fill to proper level.
4. Air leak between pump and reservoir. 4. Repair as necessary.
5. Reservoir cap not installed correctly. 5. Install reservoir cap correctly.
SCRUBBING OR
KNOCKING1. Wrong tire size. 1. Verify tire size.
19 - 2 STEERINGDR
STEERING (Continued)

BINDING AND STICKING
CONDITION POSSIBLE CAUSE CORRECTION
DIFFICULT TO TURN WHEEL
STICKS OR BINDS1. Low fluid level. 1. Fill to proper level.
2. Tire pressure. 2. Adjust tire pressure.
3. Steering components (ball
joints/tie rod ends).3 Inspect and repair as necessary.
4. Loose belt. 4. Adjust or replace.
5. Low pump pressure. 5. Pressure test and replace if
necessary.
6. Column shaft coupler binding. 6. Replace coupler.
7. Steering gear worn. 7. Replace gear.
8. Pump seized / Stuck valve 8. Replace pump.
INSUFFICIENT ASST. OR POOR RETURN TO CENTER
CONDITION POSSIBLE CAUSE CORRECTION
HARD TURNING OR MOMENTARY
INCREASE IN TURNING EFFORT1. Tire pressure. 1. Adjust tire pressure.
2. Low fluid level. 2. Fill to proper level.
3. Loose belt. 3. Adjust or replace.
4. Low pump pressure. 4. Pressure test and repair as
necessary.
5. Internal gear leak. 5. Replace gear.
STEERING WHEEL DOES NOT
WANT TO RETURN TO CENTER
POSITION1. Tire pressure. 1. Adjust tire pressure.
2. Wheel alignment. 2. Align front end.
3. Lack of lubrication. 3. Inspect and lubricate suspension
compnents.
4. High friction in steering gear. 4. Replace gear.
LOOSE STEERING AND VEHICLE LEAD
CONDITION POSSIBLE CAUSE CORRECTION
EXCESSIVE PLAY IN STEERING
WHEEL1. Worn or loose suspension or
steering components.1. Inspect and repair as necessary.
2. Worn or loose wheel bearings. 2. Inspect and repair or adjust
bearings.
3. Steering gear mounting. 3. Tighten gear mounting bolts to
specification.
4. Gear out of adjustment. 4. Replace gear.
5. Worn or loose steering coupler. 5. Inspect and replace as
necessary.
VEHICLE PULLS OR LEADS TO
ONE SIDE.1. Tire Pressure. 1. Adjust tire pressure.
2. Radial tire lead. 2. Rotate tires.
3. Brakes dragging. 3. Repair as necessary.
4. Wheel alignment. 4. Align front end.
DRSTEERING 19 - 3
STEERING (Continued)

DIAGNOSIS AND TESTING - POWER STEERING
FLOW AND PRESSURE
The following procedure is used to test the opera-
tion of the power steering system on the vehicle. This
test will provide the gallons per minute (GPM) or
flow rate of the power steering pump along with the
maximum relief pressure. Perform test any time a
power steering system problem is present. This test
will determine if the power steering pump or power
steering gear is not functioning properly. The follow-
ing pressure and flow test is performed using Power
Steering Analyzer Tool kit 6815 and (Fig. 2) Adapter
Kit 6893.
FLOW AND PRESSURE TEST
(1) Check the power steering belt to ensure it is in
good condition and adjusted properly.
(2) Connect pressure gauge hose from the Power
Steering Analyzer to adapter 6826.
(3) Connect tube 6825A to Power Steering Ana-
lyzer test valve end.
(4) Disconnect the high pressure hose from the
power steering pump.
(5) Connect the tube 6825A to the pump fitting.
(6) Connect the power steering hose from the
steering gear to the adapter 6826.
(7) Open the test valve completely.
(8) Start engine and let idle long enough to circu-
late power steering fluid through flow/pressure test
gauge and to get air out of the fluid. Then shut off
engine.(9) Check fluid level, add fluid as necessary. Start
engine again and let idle.
(10) Gauge should read below 862 kPa (125 psi), if
above, inspect the hoses for restrictions and repair as
necessary. The initial pressure reading should be in
the range of 345-552 kPa (50-80 psi).
(11) Increase the engine speed to 1500 RPM and
read the flow meter. If the flow rate (GPM) is below
specification, (refer to pump specification chart for
GPM) the pump should be replaced.
CAUTION: The following test procedure involves
testing maximum pump pressure output and flow
control valve operation. Do not leave valve closed
for more than three seconds as the pump could be
damaged.
(12) Close valve fully three times and record high-
est pressure indicated each time.All three read-
ings must be above specifications and within
345 kPa (50 psi) of each other.
²Pressures above specifications but not within
345 kPa (50 psi) of each other, replace pump.
²Pressures within 345 kPa (50 psi) of each other
but below specifications, replace pump.
(13) Open the test valve and turn the steering
wheel to the extreme left and right positions three
times against the stops. Record the highest pressure
reading at each position. Compare readings to the
pump specifications chart. If pressures readings are
not within 50 psi of each other, the gear is leaking
internally and must be replaced.
CAUTION: Do not force the pump to operate against
the stops for more than 2 to 3 seconds at a time
because, pump damage will result.PUMP SPECIFICATION
ENGINERELIEF PRESSURE
 65FLOW RATE
(GPM) AT 1500
RPM
1500
series11032 kPa
(1615   65 psi)3.1 - 3.5
2500 &
3500
series12400 kPa
(1800   50 psi)3.5 - 4.0
Fig. 2 Analyzer With Tube and Adapter
1 - TUBE
2 - ADAPTER FITTINGS
3 - ANALYZER
4 - GAUGE HOSE
19 - 4 STEERINGDR
STEERING (Continued)

Inspect output shaft bearing retainer, the
U-shaped retainer must be flat and free of distortion.
Replace the retainer if the threads are damaged or if
the retainer is bent or cracked.
COUNTERSHAFT BEARINGS AND RACES
The countershaft bearings and races are machine
lapped during manufacture to form matched sets.
The bearings and races should not be interchanged.
NOTE: The bearing races are a permanent press fit
in the housings and are NOT serviceable. If a bear-
ing race becomes damaged, the front or rear hous-
ing must be replaced. A new countershaft bearing
will be supplied with each new housing for service
use.
REVERSE IDLER COMPONENTS
Inspect the idler gear, bearing, shaft, thrust
washer, wave washer and thrust plate. Replace the
bearing if any of the needle bearing rollers are worn,
chipped, cracked, flat-spotted or brinnelled. Also
replace the bearing if the plastic bearing cage is
damaged or distorted.
Replace thrust washer, wave washer or thrust
plate if cracked, chipped or worn. Replace idler gear
if the teeth are chipped, cracked or worn thin.
Replace shaft if worn, scored or the bolt threads are
damaged beyond repair. Replace support segment if
cracked or chipped and replace the idler attaching
bolts if the threads are damaged.
Shift Socket
Inspect the shift socket for wear or damage.
Replace the socket if the roll pin or shift shaft bores
are damaged. Minor nicks in the shift lever ball seat
in the socket can be smoothed down with 400 grit
emery or wet/dry paper. Replace the socket if the ball
seat is worn or cracked. Do not reuse the original
shift socket roll pin. Install anewpin during assem-
bly. The socket roll pin is approximately 33 mm
(1-1/4 in.) long.
Output Shaft And Geartrain
Inspect all gears for worn, cracked, chipped or bro-
ken teeth. Also check condition of the bearing bore in
each gear. The bores should be smooth and free of
surface damage. Discoloration of the gear bores is a
normal occurrence and is not a reason for replace-
ment. Replace gears only when tooth damage has
occurred or if the bores are brinnelled or severely
scored.
Inspect the shaft splines and bearings surfaces.
Minor nicks on the bearing surfaces can be smoothed
with 320/420 grit emery and final polished with cro-
cus cloth. Replace the shaft if the splines are dam-aged or bearing surfaces are deeply scored, worn or
brinnelled.
ASSEMBLY
NOTE: Sealers are used at all case joints. Use
Mopar Gasket Maker or equivalent for all case joints
and Mopar silicone sealer or equivalent for the
input shaft bearing retainer.
SYNCHRONIZER
(1) Slide sleeve onto the hub, leaving enough room
to install the spring in the hub and strut in the hub
groove.
(2) Install first spring in the hub, then install a
strut over the spring. Verify spring is seated in the
spring bore in the strut.
(3) Slide sleeve onto the hub far enough to hold
the first strut and spring in place.
(4) Place detent ball in the top of the strut, then
press the ball into place with a small screwdriver.
Work the sleeve over the ball to hold it in place.
(5) Repeat procedure for the remaining springs,
struts and balls. Use tape or rubber bands to tempo-
rarily secure each strut and ball as they are
installed.
(6) Verify the synchro three springs, struts and
detent balls are all in place (Fig. 49).
Fig. 49 SYNCHRONIZER COMPONENTS
1 - SLEEVE
2 - HUB SHOULDER
3 - SPRING (3)
4 - STRUT (3)
5 - DETENT BALL (3)
6 - HUB
DRMANUAL TRANSMISSION - NV3500 21 - 17
MANUAL TRANSMISSION - NV3500 (Continued)

(28) Remove reverse clutch gear (Fig. 62).
(29) Remove first gear from bearing and mainshaft
(Fig. 63).
(30) Remove first gear bearing from mainshaft
(Fig. 64).
CLEANING
Clean the gears, shafts, shift components and
transmission housings with a standard parts clean-
ing solvent. Do not use acid or corrosive base sol-
vents. Dry all parts except bearings with compressed
air.
Clean the shaft bearings with a mild solvent such
as Mopar degreasing solvent, Gunk or similar sol-
vents. Do not dry the bearings with compressed air.
Allow the bearings to either air dry or wipe them dry
with clean shop towels.
INSPECTION
NOTE: Minor corrosion, nicks, or pitting can be
smoothed with 400 grit emery and polished out with
crocus cloth.
Inspect the reverse idler gear, bearings, shaft and
thrust washers. Replace the bearings if the rollers
are worn, chipped, cracked, flat-spotted or brinnelled.
Replace the gear if the teeth are chipped, cracked or
worn thin.
Inspect the front bearing retainer and bearing cup.
Replace the bearing cup if scored, cracked, brinnelled
or rough. Check the release bearing slide surface of
the retainer carefully. Replace the retainer if worn or
damaged in any way.
Inspect mainshaft bearing surfaces, splines, snap
ring grooves and threads. Replace the shaft if any
surfaces exhibit considerable wear or damage.
Inspect the countershaft and bearings. Replace the
shaft if any surfaces exhibit considerable wear or
damage.
Inspect shift forks for wear and distortion. Check
fit of the sleeve in the fork to be sure the two parts
fit and work smoothly. Replace the fork if the roll pin
holes are worn oversize or damaged. Do not attempt
to salvage a worn fork. Replace shift fork roll pins if
necessary or if doubt exists about their condition.
The all bearings for wear, roughness, flat spots,
pitting or other damage. Replace the bearings if nec-
essary.
Inspect the blocker rings and fiction cones. replace
either part if worn or damaged in any way. Replace if
the friction material is burned, flaking off or worn.
Inspect synchro components wear or damage.
Replace parts if worn, cracked or distorted.
Inspect all of the thrust washers and locating pins.
Replace the pins if bent or worn. Replace the wash-
ers if worn or the locating pin notches are distorted.
Inspect the case and housing/adapter sealing and
mating surfaces are free of burrs and nicks. InspcetFig. 62 Reverse Clutch Gear
1 - REVERSE CLUTCH GEAR
Fig. 63 FIRST GEAR
1 - FIRST GEAR
Fig. 64 FIRST GEAR BEARING
1 - MAINSHAFT
2 - FIRST GEAR BEARING
21 - 62 MANUAL TRANSMISSION - NV4500DR
MANUAL TRANSMISSION - NV4500 (Continued)

(5) Remove input shaft oil guide and retainer seal
(Fig. 50).
CLEANING - TRANSMISSION
Clean the gears, bearings shafts, extension/adapter
housing and gear case with solvent. Dry all parts
except the bearings with compressed air. Allow the
bearings to either air dry or wipe them dry with
clean shop towels.
INSPECTION
NOTE: Minor corrosion, nicks, or pitting can be
smoothed with 400 grit emery and polished out with
crocus cloth.
Inspect the reverse idler gear, bearings, shaft and
thrust washers. Replace the bearings if the rollers
are worn, chipped, cracked, flat-spotted or brinnelled.
Replace the gear if the teeth are chipped, cracked or
worn thin.
Inspect the front bearing retainer and bearing cup.
Replace the bearing cup if scored, cracked, brinnelled
or rough. Check the release bearing slide surface of
the retainer carefully. Replace the retainer if worn or
damaged in any way.
Inspect mainshaft bearing surfaces, splines, snap
ring grooves and threads. Replace the shaft if any
surfaces exhibit considerable wear or damage.
Inspect the countershaft and bearings. Replace the
shaft if any surfaces exhibit considerable wear or
damage.Inspect shift forks for wear and distortion. Check
fit of the sleeve in the fork to be sure the two parts
fit and work smoothly. Replace the fork if the roll pin
holes are worn oversize or damaged. Do not attempt
to salvage a worn fork. Replace shift fork roll pins if
necessary or if doubt exists about their condition.
The all bearings for wear, roughness, flat spots,
pitting or other damage. Replace the bearings if nec-
essary.
Inspect the blocker rings and fiction cones. replace
either part if worn or damaged in any way. Replace if
the friction material is burned, flaking off or worn.
Inspect synchro components wear or damage.
Replace parts if worn, cracked or distorted.
Inspect all of the thrust washers and locating pins.
Replace the pins if bent or worn. Replace the wash-
ers if worn or the locating pin notches are distorted.
Inspect the case and housing/adapter sealing and
mating surfaces are free of burrs and nicks. Inspcet
the alignment dowels in the case top surface and in
the housing/adapter are tight and in good condition.
Replace the gear case or housing/adapter if cracked
or broken.
ASSEMBLY
NOTE: Gaskets are not used in the transmission.
Use Mopar Gasket Maker or equivalent on all gear
case and extension housing sealing surfaces.
OUTPUT SHAFT
(1) Place second gear on bench with the synchro
clutch ring up.
(2) Install second gear synchro inner blocker ring
onto second gear (Fig. 51).
Fig. 50 OIL GUIDE AND SEAL
1 - INPUT SHAFT OIL GUIDE
2 - INPUT SHAFT OIL SEAL
Fig. 51 INNER BLOCKER RING
1 - INNER BLOCKER RING
2 - GEAR
21 - 106 MANUAL TRANSMISSION - NV5600DR
MANUAL TRANSMISSION - NV5600 (Continued)