IPM DODGE RAM 1500 1998 2.G Workshop Manual

INTRODUCTION
TABLE OF CONTENTS
page page
VEHICLE IDENTIFICATION NUMBER
DESCRIPTION..........................1
VEHICLE EMISSION CONTROL INFORMATION
(VECI)
DESCRIPTION..........................2
BODY CODE PLATE
DESCRIPTION..........................3
INTERNATIONAL VEHICLE CONTROL &
DISPLAY SYMBOLS
DESCRIPTION - INTERNATIONAL SYMBOLS . . . 5
FASTENER IDENTIFICATION
DESCRIPTION..........................5FASTENER USAGE
DESCRIPTION - FASTENER USAGE.........8
THREADED HOLE REPAIR
DESCRIPTION - THREADED HOLE REPAIR....8
METRIC SYSTEM
DESCRIPTION..........................8
TORQUE REFERENCES
DESCRIPTION.........................10
VEHICLE CERTIFICATION LABEL
DESCRIPTION.........................11
VEHICLE IDENTIFICATION
NUMBER
DESCRIPTION
VIN CODING/LOCATIONS
The Vehicle Identification Number (VIN) plate is
located on the lower windshield fence near the left
a-pillar (Fig. 1). The VIN contains 17 characters that
provide data concerning the vehicle. Refer to the VIN
decoding chart to determine the identification of a
vehicle.
The VIN is also imprinted on the:
²Body Code Plate.
²Equipment Identification Plate.
²Vehicle Safety Certification Label.
²Frame rail.
To protect the consumer from theft and possible
fraud the manufacturer is required to include a
Check Digit at the ninth position of the VIN. The
check digit is used by the manufacturer and govern-
ment agencies to verify the authenticity of the vehi-cle and official documentation. The formula to use
the check digit is not released to the general public.
POSITION INTERPRETATION CODE = DESCRIPTION
1 Country of Origin 1 = Manufactured By DaimlerChrysler Corporation
3 = Manufactured By DaimlerChrysler De Mexico
2 Make D = Dodge
3 Vehicle Type 2 = Incomplete with Side Airbag
3 = Truck with Side Airbag
6 = Incomplete Less Side Airbag
7 = Truck Less Side Airbag
Fig. 1 VIN LOCATION
1 - DASH PANEL
2 - VIN CODE PLATE
DRINTRODUCTION 1

tic and soften solder. The increased temperature can
result in engine detonation. In addition, 100 percent
ethylene-glycol freezes at -22ÉC (-8ÉF).
50/50 Ethylene-Glycol and Water-Is the recom-
mended mixture, it provides protection against freez-
ing to -37ÉC (-34ÉF). The antifreeze concentration
must alwaysbe a minimum of 44 percent, year-
round in all climates. If percentage is lower, engine
parts may be eroded by cavitation. Maximum protec-
tion against freezing is provided with a 68 percent
antifreeze concentration, which prevents freezing
down to -67.7ÉC (-90ÉF). A higher percentage will
freeze at a warmer temperature. Also, a higher per-
centage of antifreeze can cause the engine to over-
heat because specific heat of antifreeze is lower than
that of water.
CAUTION: Richer antifreeze mixtures cannot be
measured with normal field equipment and can
cause problems associated with 100 percent ethyl-
ene-glycol.
COOLANT SELECTION AND ADDITIVES
NOTE: Refer to the vehicle's coolant bottle to iden-
tify HOAT or Non-HOAT coolant. Non-HOAT coolant
is green in color.
The use of aluminum cylinder blocks, cylinder
heads and water pumps requires special corrosion
protection. Only MopartAntifreeze/Coolant, 5
Year/100,000 Mile Formula (glycol base coolant with
corrosion inhibitors called HOAT, for Hybrid Organic
Additive Technology) is recommended. This coolant
offers the best engine cooling without corrosion when
mixed with 50% distilled water to obtain to obtain a
freeze point of -37ÉC (-35ÉF). If it loses color or
becomes contaminated, drain, flush, and replace with
fresh properly mixed coolant solution.
CAUTION: Do not use coolant additives that are
claimed to improve engine cooling.
DESCRIPTION - TRANSFER CASE
Recommended lubricant for the NV241 GENII,
NV271, NV243, NV244 GENII, and NV273 transfer
cases is MopartATF +4, Automatic Transmission
Fluid.
DESCRIPTION - AXLE
NOTE: DaimlerChrysler recommends using MoparT
lubricants or lubricants of equal quality.
FRONT AXLE
²C205F - MopartGear Lubricant 75W-90
²9 1/4 AA - MopartSynthetic Gear Lubricant
75W-90
REAR AXLE
²9 1/4 - MopartSynthetic Gear Lubricant 75W-
140
²10 1/2 AA - MopartSynthetic Gear Lubricant
75W-90
²11 1/2 AA - MopartSynthetic Gear Lubricant
75W-90
NOTE: Trac-LokTdifferentials require Limited Slip
Additive in the lubricant. Trac-RiteŸ differentials
DO NOT require Limited Slip Additive.
DESCRIPTION - MANUAL TRANSMISSION
NOTE: DaimlerChrysler recommends using MoparT
lubricants or lubricants of equal quality.
²NV3500 - MopartManual Transmission Lubri-
cant
²NV4500 - MopartSynthetic 75W85 Manual
Transmission Lubricant
²NV5600 - MopartManual Transmission Lubri-
cant
DESCRIPTION - AUTOMATIC TRANSMISSION
FLUID
NOTE: Refer to Service Procedures in this group for
fluid level checking procedures.
MopartATF +4, Automatic Transmission Fluid is
the recommended fluid for DaimlerChrysler auto-
matic transmissions.
Dexron II fluid IS NOT recommended. Clutch
chatter can result from the use of improper
fluid.
MopartATF +4, Automatic Transmission Fluid
when new is red in color. The ATF is dyed red so it
can be identified from other fluids used in the vehicle
such as engine oil or antifreeze. The red color is not
permanent and is not an indicator of fluid condition.
As the vehicle is driven, the ATF will begin to look
darker in color and may eventually become brown.
This is normal.ATF+4 also has a unique odor that
may change with age. Consequently, odor and color
cannot be used to indicate the fluid condition or the
need for a fluid change.
0 - 4 LUBRICATION & MAINTENANCEDR
FLUID TYPES (Continued)

Miles 102,000 108,000 114,000 120,000
(Kilometers) (163 000) (173 000) (182 000) (192 000)
[Months] [102] [108] [114] [120]
Change engine oil and engine oil filter. X X X X
Drain and refill transfer case fluid (4X4). X
Flush and replace engine coolant, if not done at 60 mos. X
Lubricate outer tie rod ends 2500/3500 (4X4) models
only.XXX X
Inspect brake linings. X
Inspect auto tension drive belt and replace if required
(3.7L/4.7L/5.7L).X³X³
Replace ignition cables.X
Replace engine air cleaner filter.X
Replace spark plugs.X
Inspect PCV Valve, replace as necessary X*
* This maintenance is recommended by the manu-
facture to the owner but is not required to maintain
the emissions warranty.
³ This maintenance is not required if previously
replaced.
Inspection and service should also be performed
anytime a malfunction is observed or suspected.
WARNING: You can be badly injured working on or
around a motor vehicle. Do only that service work
for which you have the knowledge and the right
equipment. If you have any doubt about your ability
to perform a service job, take your vehicle to a
competent mechanic.
MAINTENANCE SCHEDULES Ð 24±VALVE
CUMMINS TURBO DIESEL
There are two maintenance schedules that show
therequiredservice for your vehicle.
First is ScheduleªBº. It is for vehicles that are
operated under the conditions that are listed below
and at the beginning of the schedule.
²Day or night temperatures are below 0É C (32É
F).
²Stop and go driving.
²Extensive engine idling.
²Driving in dusty conditions.
²Short trips of less than 16 km (10 miles).
²More than 50% of your driving is at sustained
high speeds during hot weather, above 32É C (90É F).²Trailer towing.
²Taxi, police, or delivery service (commercial ser-
vice).
²Off-road or desert operation.
NOTE: Most vehicles are operated under the condi-
tions listed for Schedule(B(.
Second is ScheduleªAº. It is for vehicles that are
not operated under any of the conditions listed under
Schedule9B9.
Use the schedule that best describes your driving
conditions. Where time and mileage are listed, follow
the interval that occurs first.
CAUTION: Failure to perform the required mainte-
nance items may result in damage to the vehicle.At Each Stop for Fuel
²Check the engine oil level about 15 minutes
after a fully warmed engine is shut off. Checking the
oil level while the vehicle is on level ground will
improve the accuracy of the oil level reading. Add oil
only when the level is at or below the ADD or MIN
mark.
²Check the windshield washer solvent and add if
required.
²Drain water from the fuel filter.
0 - 12 LUBRICATION & MAINTENANCEDR
MAINTENANCE SCHEDULES (Continued)

Miles 112,500 120,000 127,500 135,000 142,500 150,000
(Kilometers) (181 000) (193 000) (205 000) (217 000) (229 000) (241 000)
[Months] [90] [96] [102] [108] [114] [150]
Inspect front wheel bearings. X X
Inspect brake linings. X X
Inspect and adjust parking
brake if necessary.XX
Adjust valve lash clearance.X
²LTier 1 EPA (250 hp or 305 hp) Engines Only
(see engine data label for your engine type)
²² California LEV (235 hp) Engines Only (see
engine data label for your engine type)
Inspection and service should also be performed
anytime a malfunction is observed or suspected.
WARNING: You can be badly injured working on or
around a motor vehicle. Do only that service work
for which you have the knowledge and the right
equipment. If you have any doubt about your ability
to perform a service job, take your vehicle to a
competent mechanic.
JUMP STARTING
STANDARD PROCEDURE - JUMP STARTING
WARNING: REVIEW ALL SAFETY PRECAUTIONS
AND WARNINGS IN THE BATTERY SYSTEM SEC-
TION OF THE SERVICE MANUAL. (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/BATTERY - STAN-
DARD PROCEDURE)
²DO NOT JUMP START A FROZEN BATTERY,
PERSONAL INJURY CAN RESULT.
²IF EQUIPPED, DO NOT JUMP START WHEN
MAINTENANCE FREE BATTERY INDICATOR DOT IS
YELLOW OR BRIGHT COLOR.
²DO NOT JUMP START A VEHICLE WHEN THE
BATTERY FLUID IS BELOW THE TOP OF LEAD
PLATES.
²DO NOT ALLOW JUMPER CABLE CLAMPS TO
TOUCH EACH OTHER WHEN CONNECTED TO A
BOOSTER SOURCE.
²DO NOT USE OPEN FLAME NEAR BATTERY.
²REMOVE METALLIC JEWELRY WORN ON
HANDS OR WRISTS TO AVOID INJURY BY ACCI-
DENTAL ARCING OF BATTERY CURRENT.
²WHEN USING A HIGH OUTPUT BOOSTING
DEVICE, DO NOT ALLOW BATTERY VOLTAGE TO
EXCEED 16 VOLTS. REFER TO INSTRUCTIONS
PROVIDED WITH DEVICE BEING USED.FAILURE TO FOLLOW THESE INSTRUCTIONS MAY
RESULT IN PERSONAL INJURY.
CAUTION: When using another vehicle as a
booster, do not allow vehicles to touch. Electrical
systems can be damaged on either vehicle.
TO JUMP START A DISABLED VEHICLE:
(1) Raise hood on disabled vehicle and visually
inspect engine compartment for:
²Battery cable clamp condition, clean if necessary.
²Frozen battery.
²Yellow or bright color test indicator, if equipped.
²Low battery fluid level.
²Generator drive belt condition and tension.
²Fuel fumes or leakage, correct if necessary.
CAUTION: If the cause of starting problem on dis-
abled vehicle is severe, damage to booster vehicle
charging system can result.
(2) When using another vehicle as a booster
source, park the booster vehicle within cable reach.
Turn off all accessories, set the parking brake, place
the automatic transmission in PARK or the manual
transmission in NEUTRAL and turn the ignition
OFF.
(3) On disabled vehicle, place gear selector in park
or neutral and set park brake. Turn off all accesso-
ries.
(4) Connect jumper cables to booster battery. RED
clamp to positive terminal (+). BLACK clamp to neg-
ative terminal (-). DO NOT allow clamps at opposite
end of cables to touch, electrical arc will result.
Review all warnings in this procedure.
(5) On disabled vehicle, connect RED jumper cable
clamp to positive (+) terminal. Connect BLACK
jumper cable clamp to engine ground as close to the
ground cable attaching point as possible.
(6) Start the engine in the vehicle which has the
booster battery, let the engine idle a few minutes,
then start the engine in the vehicle with the dis-
charged battery.
DRLUBRICATION & MAINTENANCE 0 - 19
MAINTENANCE SCHEDULES (Continued)

TOWING
STANDARD PROCEDURE - TOWING
A vehicle equipped with SAE approved sling-type
towing equipment can be used to tow all vehicles.
When towing a 4WD vehicle using a wheel-lift towing
device, use tow dollies under the opposite end of the
vehicle. A vehicle with flat-bed device can also be
used to transport a disabled vehicle (Fig. 10).
Fig. 7 Vehicle Lifting Locations
Fig. 8 FRONT LIFT PAD LOCATION
1 - BODY MOUNT BRACKET
2 - FRONT LIFT PAD
3 - TRANSMISSION CROSSMEMBER BRACKET
4 - FRAME RAIL
Fig. 9 REAR LIFT PAD LOCATION
1 - FRAME RAIL
2 - REAR LIFT PAD
3 - LEAF SPRING MOUNTING BRACKET
4 - BOX MOUNTING BRACKET
Fig. 10 Tow Vehicles With Approved Equipment
1 - SLING TYPE
2 - WHEEL LIFT
3 - FLAT BED
DRLUBRICATION & MAINTENANCE 0 - 21
TOWING (Continued)

A wooden crossbeam may be required for proper
connection when using the sling-type, front-end tow-
ing method.
SAFETY PRECAUTIONS
CAUTION: The following safety precautions must be
observed when towing a vehicle:
²Secure loose and protruding parts.
²Always use a safety chain system that is inde-
pendent of the lifting and towing equipment.
²Do not allow towing equipment to contact the
disabled vehicle's fuel tank.
²Do not allow anyone under the disabled vehicle
while it is lifted by the towing device.
²Do not allow passengers to ride in a vehicle
being towed.
²Always observe state and local laws regarding
towing regulations.
²Do not tow a vehicle in a manner that could
jeopardize the safety of the operator, pedestrians or
other motorists.
²Do not attach tow chains, T-hooks, J-hooks, or a
tow sling to a bumper, steering linkage, drive shafts
or a non-reinforced frame hole.
²Do not tow a heavily loaded vehicle. Damage to
the cab, cargo box or frame may result. Use a flatbed
device to transport a loaded vehicle.
GROUND CLEARANCE
CAUTION: If vehicle is towed with wheels removed,
install lug nuts to retain brake drums or rotors.
A towed vehicle should be raised until lifted wheels
are a minimum 100 mm (4 in) from the ground. Be
sure there is adequate ground clearance at the oppo-
site end of the vehicle, especially when towing over
rough terrain or steep rises in the road. If necessary,remove the wheels from the lifted end of the vehicle
and lower the vehicle closer to the ground, to
increase the ground clearance at the opposite end of
the vehicle. Install lug nuts on wheel attaching studs
to retain brake drums or rotors.
RAMP ANGLE
If a vehicle with flat-bed towing equipment is used,
the approach ramp angle should not exceed 15
degrees.
TOWING WHEN KEYS ARE NOT AVAILABLE
When the vehicle is locked and keys are not avail-
able, use a flat bed hauler. A Wheel-lift or Sling-type
device can be used on 4WD vehicles providedall the
wheels are lifted off the ground using tow dol-
lies.
FOUR-WHEEL-DRIVE VEHICLE TOWING
Chrysler Corporation recommends that a vehicle be
transported on a flat-bed device. A Wheel-lift or
Sling-type device can be used providedall the
wheels are lifted off the ground using tow dol-
lies.
WARNING: WHEN TOWING A DISABLED VEHICLE
AND THE DRIVE WHEELS ARE SECURED IN A
WHEEL LIFT OR TOW DOLLIES, ENSURE THE
TRANSMISSION IS IN THE PARK POSITION (AUTO-
MATIC TRANSMISSION) OR A FORWARD DRIVE
GEAR (MANUAL TRANSMISSION).
CAUTION: Many vehicles are equipped with air
dams, spoilers, and/or ground effect panels. To
avoid component damage, a wheel-lift towing vehi-
cle or a flat-bed hauling vehicle is recommended.
0 - 22 LUBRICATION & MAINTENANCEDR
TOWING (Continued)

of chatter are out-of-tolerance rotors, brake lining not
securely attached to the shoes, loose wheel bearings
and contaminated brake lining.
THUMP/CLUNK NOISE
Thumping or clunk noises during braking are fre-
quentlynotcaused by brake components. In many
cases, such noises are caused by loose or damaged
steering, suspension, or engine components. However,
calipers that bind on the slide surfaces can generate
a thump or clunk noise.
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL BLEEDING
Use Mopar brake fluid, or an equivalent quality
fluid meeting SAE J1703-F and DOT 3 standards
only. Use fresh, clean fluid from a sealed container at
all times.
(1) Remove reservoir filler caps and fill reservoir.
(2) If calipers were overhauled, open all caliper
bleed screws. Then close each bleed screw as fluid
starts to drip from it. Top off master cylinder reser-
voir once more before proceeding.
(3) Attach one end of bleed hose to bleed screw
and insert opposite end in glass container partially
filled with brake fluid (Fig. 1). Be sure end of bleed
hose is immersed in fluid.
NOTE: Bleed procedure should be in this order (1)
Right rear (2) Left rear (3) Right front (4) Left front.(4) Open up bleeder, then have a helper press
down the brake pedal. Once the pedal is down close
the bleeder. Repeat bleeding until fluid stream is
clear and free of bubbles. Then move to the next
wheel.
(5) Before moving the vehicle verify the pedal is
firm and not mushy.
(6) Top off the brake fluid and install the reservoir
cap.
STANDARD PROCEDURE - PRESSURE
BLEEDING
Use Mopar brake fluid, or an equivalent quality
fluid meeting SAE J1703-F and DOT 3 standards
only. Use fresh, clean fluid from a sealed container at
all times.
Follow the manufacturers instructions carefully
when using pressure equipment. Do not exceed the
tank manufacturers pressure recommendations. Gen-
erally, a tank pressure of 15-20 psi is sufficient for
bleeding.
Fill the bleeder tank with recommended fluid and
purge air from the tank lines before bleeding.
Do not pressure bleed without a proper master cyl-
inder adapter. The wrong adapter can lead to leak-
age, or drawing air back into the system.
SPECIAL TOOLS
BASE BRAKES
Fig. 1 Bleed Hose Setup
1 - BLEED HOSE
2 - FLUID CONTAINER PARTIALLY FILLED WITH FLUID
INSTALLER, BRAKE CALIPER DUST BOOT C-4340
INSTALLER, BRAKE CALIPER DUST BOOT
C-3716-A
DRBRAKES - BASE 5 - 5
BRAKES - BASE (Continued)

FRONT WHEEL SPEED
SENSOR
DESCRIPTION
The ABS brake system uses 3 wheel speed sensors.
A sensor is mounted to each front hub/bearings. The
third sensor is mounted on top of the rear axle dif-
ferential housing.
OPERATION
The Wheel Speed Sensor consists of a magnet sur-
rounded by windings from a single strand of wire.
The sensor sends a small AC signal to the CAB. This
signal is generated by magnetic induction. The mag-
netic induction is created when a toothed sensor ring
(exciter ring or tone wheel) passes the stationary
magnetic WSS.
When the ring gear is rotated, the exciter ring
passes the tip of the WSS. As the exciter ring tooth
approaches the tip of the WSS, the magnetic lines of
force expand, causing the magnetic field to cut across
the sensor's windings. This, in turn causes current to
flow through the WSS circuit (Fig. 1) in one direc-
tion. When the exciter ring tooth moves away from
the sensor tip, the magnetic lines of force collapse
cutting the winding in the opposite direction. This
causes the current to flow in the opposite direction.
Every time a tooth of the exciter ring passes the tip
of the WSS, an AC signal is generated. Each AC sig-
nal (positive to negative signal or sinewave) is inter-
preted by the CAB. It then compares the frequency of
the sinewave to a time value to calculate vehicle
speed. The CAB continues to monitor the frequency
to determine a deceleration rate that would indicate
a possible wheel-locking tendency.
The signal strength of any magnetic induction sen-
sor is directly affected by:
²Magnetic field strength; the stronger the mag-
netic field, the stronger the signal
²Number of windings in the sensor; more wind-
ings provide a stronger signal
²Exciter ring speed; the faster the exciter ring/
tone wheel rotates, the stronger the signal will be
²Distance between the exciter ring teeth and
WSS; the closer the WSS is to the exciter ring/tone
wheel, the stronger the signal will be
The rear WSS is not adjustable. A clearance speci-
fication has been established for manufacturing toler-
ances. If the clearance is not within these
specifications, then either the WSS or other compo-
nents may be damaged. The clearance between the
WSS and the exciter ring is 0.005 ± 0.050 in.
The assembly plant performs a ªRolls Testº on
every vehicle that leaves the assembly plant. One of
the test performed is a test of the WSS. To properlytest the sensor, the assembly plant connects test
equipment to the Data Link Connector (DLC). This
connector is located to the right of the steering col-
umn and attached to the lower portion of the instru-
ment panel (Fig. 2). The rolls test terminal is spliced
to the WSS circuit. The vehicle is then driven on a
set of rollers and the WSS output is monitored for
proper operation.
Fig. 1 Operation of the Wheel Speed Sensor
1 - MAGNETIC CORE
2 - CAB
3 - AIR GAP
4 - EXCITER RING
5 - COIL
Fig. 2 Data Link Connector - Typical
1 - 16±WAY DATA LINK CONNECTOR
DRBRAKES - ABS 5 - 47

PRESSURE INCREASE
The inlet valve is open and the outlet valve is
closed during the pressure increase cycle. The pres-
sure increase cycle is used to reapply thew brakes.
This cycle controls re-application of fluid apply pres-
sure.
REMOVAL
(1) Install a prop rod on the brake pedal to keep
pressure on the brake system.
(2) Disconnect the battery cables from the battery.
(3) Remove the battery.
(4) Disconnect the two electrical harness connec-
tors (Fig. 5).
(5) Remove the five brake lines from the HCU
(Fig. 5).
(6) Remove HCU/CAB mounting bolts and remove
the HCU/CAB (Fig. 5).
INSTALLATION
NOTE: If the CAB is being replaced with a new CAB
is must be reprogrammed with the use of a DRB III.
(1) Install HCU/CAB on the mounts and Tighten
the bolts to 15N´m (11 ft. lbs.) (Fig. 5).
(2) Install the five brake lines to the HCU and
tighten to 19 N´m (170 in. lbs.) (Fig. 5).
(3) Install the two electrical harness connectors to
the HCU/CAB and push down on the release to
secure the connectors.
(4) Install the battery.
(5) Install the battery cables to the battery.
(6) Remove the prop rod on the brake pedal.
(7) Bleed ABS brake system (Refer to 5 - BRAKES
- STANDARD PROCEDURE).
RWAL VALVE
DESCRIPTION
Rear Wheel Antilock (RWAL) brake system is stan-
dard equipment on 1500 series vehicles. The RWAL
brake system is designed to prevent rear wheel
lock-up on virtually all types of road surfaces. RWAL
braking is desirable because a vehicle which is
stopped without locking the rear wheels will retain
directional stability. This allows the driver to retain
greater control of the vehicle during braking.
The valve is located on the drivers side inner
fender under the hood. The valve modulates hydrau-
lic pressure to the rear brakes.
The RWAL components include:
²RWAL Valve
²Controller Antilock brake (CAB)
²Rear Wheel Speed Sensor (WSS)
OPERATION
When the brakes are applied, hydraulic fluid is
routed from the master cylinder's secondary circuit to
the RWAL valve. From there hydraulic fluid is routed
to the rear brakes. The Controller Antilock Brake
(CAB) contains an Electronic Variable Brake Propor-
tioning (EVBP) control algorithm, which proportions
the applied braking force to the rear wheels during
braking. The EVBP function of the RWAL system
takes the place of a conventional hydraulic propor-
tioning valve. The CAB monitors the rear wheel
speed through the rear wheel speed sensor and cal-
culates an estimated vehicle deceleration. When an
established deceleration threshold is exceeded, an
isolation valve is closed to hold the applied brake
pressure to the rear brakes constant. Upon further
increases in the estimated vehicle deceleration, the
isolation valve is selectively opened to increase rear
brake pressure in proportion to the front brake pres-
sure. If impending rear wheel lock-up is sensed, the
CAB signals the RWAL valve to modulate hydraulic
brake pressure to the rear wheels to prevent lock-up.
NORMAL BRAKING Since the RWAL valve also
performs the EVBP or proportioning function, vehicle
deceleration under normal braking may be sufficient
to trigger the EVBP function of the RWAL system
without full RWAL activity as would normally occur
during an impending rear wheel lock-up. As previ-
ously mentioned, the isolation valve is selectively
closed and opened to increase rear brake pressure in
proportion to the front brake pressure under EVBP
control. Slight brake pedal pulsations may be noticed
as the isolation valve is opened.
Fig. 5 HYDRAULIC CONTROL UNIT
1 - HYDRAULIC CONTROL UNIT
2 - MOUNTING BOLTS
5 - 50 BRAKES - ABSDR
HCU (HYDRAULIC CONTROL UNIT) (Continued)

Engagement problems can cause slip, chatter/shud-
der and noisy operation. The causes may be clutch
disc contamination, wear, distortion or flywheel dam-
age.
CLUTCH MISALIGNMENT
Clutch components must be in proper alignment
with the crankshaft and transmission input shaft.
Misalignment caused by excessive runout or warpage
of any clutch component will cause grab, chatter and
improper clutch release.
CLUTCH COVER AND DISC RUNOUT
Check the clutch disc before installation. Axial
(face) runout of anewdisc should not exceed 0.50
mm (0.020 in.). Measure runout about 6 mm (1/4 in.)
from the outer edge of the disc facing. Obtain
another disc if runout is excessive.
Check condition of the clutch before installation. A
warped cover or diaphragm spring will cause grab
and incomplete release or engagement. Be careful
when handling the cover and disc. Impact can distort
the cover, diaphragm spring, release fingers and the
hub of the clutch disc.
Use an alignment tool when positioning the disc on
the flywheel. The tool prevents accidental misalign-
ment which could result in cover distortion and disc
damage.
A frequent cause of clutch cover distortion (and
consequent misalignment) is improper bolt tighten-
ing.
FLYWHEEL RUNOUT
Check flywheel runout whenever misalignment is
suspected. Flywheel runout should not exceed 0.08
mm (0.003 in.). Measure runout at the outer edge of
the flywheel face with a dial indicator.
Common causes of runout are:
²heat warpage
²improper machining
²incorrect bolt tightening
²improper seating on crankshaft flange shoulder
²foreign material on crankshaft flange
Flywheel machining is not recommended. The fly-
wheel clutch surface is machined to a unique contour
and machining will negate this feature. Minor fly-
wheel scoring can be cleaned up by hand with 180
grit emery or with turning equipment. Remove only
enough material to reduce scoring (approximately
0.001 - 0.003 in.). Heavy stock removal isnot rec-
ommended.Replace the flywheel if scoring is severe
and deeper than 0.076 mm (0.003 in.). Excessive
stock removal can result in flywheel cracking or
warpage after installation; it can also weaken the fly-
wheel and interfere with proper clutch release.
Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may
cock the flywheel causing excessive runout. Use new
bolts when remounting a flywheel and secure the
bolts with Mopar Lock And Seal or equivalent.
Tighten flywheel bolts to specified torque only. Over-
tightening can distort the flywheel hub causing
runout.
DIAGNOSIS CHART
The diagnosis charts Diagnosis Chart describe
common clutch problems, causes and correction.
DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
Disc facing worn out 1. Normal wear. 1. Replace cover and disc.
2. Driver frequently rides (slips) the
clutch. Results in rapid overheating
and wear.2. Replace cover and disc.
3. Insufficient clutch cover
diaphragm spring tension.3. Replace cover and disc.
6 - 2 CLUTCHDR
CLUTCH (Continued)