1998 DODGE RAM 1500 ECU

GROUP TAB LOCATOR
Introduction
0Lubrication & Maintenance
2Suspension
3Differential & Driveline
5Brakes
6Clutch
7Cooling
8AAudio/Video
8BChime/Buzzer
8EElectronic Control Modules
8FEngine Systems
8GHeated Systems
8HHorn
8IIgnition Control
8JInstrument Cluster
8LLamps
8MMessage Systems
8NPower Systems
8ORestraints
8PSpeed Control
8QVehicle Theft Security
8RWipers/Washers
8TNavigation/Telecommunication
8WWiring
9Engine
11Exhaust System
13Frame & Bumpers
14Fuel System
19Steering
21Transmission and Transfer Case
22Tires/Wheels
23Body
24Heating & Air Conditioning
25Emissions Control
Component and System Index
Service Manual Comment Forms (Rear of Manual)

CAUTION: Do not crank starter motor on disabled
vehicle for more than 15 seconds, starter will over-
heat and could fail.
(7) Allow battery in disabled vehicle to charge to
at least 12.4 volts (75% charge) before attempting to
start engine. If engine does not start within 15 sec-
onds, stop cranking engine and allow starter to cool
(15 min.), before cranking again.
DISCONNECT CABLE CLAMPS AS FOLLOWS:
²Disconnect BLACK cable clamp from engine
ground on disabled vehicle.
²When using a Booster vehicle, disconnect
BLACK cable clamp from battery negative terminal.
Disconnect RED cable clamp from battery positive
terminal.
²Disconnect RED cable clamp from battery posi-
tive terminal on disabled vehicle.
HOISTING
STANDARD PROCEDURE - HOISTING
Refer to the Owner's Manual for emergency vehicle
lifting procedures.
WARNING: THE HOISTING AND JACK LIFTING
POINTS PROVIDED ARE FOR A COMPLETE VEHI-
CLE. WHEN A CHASSIS OR DRIVETRAIN COMPO-
NENT IS REMOVED FROM A VEHICLE, THE
CENTER OF GRAVITY IS ALTERED MAKING SOME
HOISTING CONDITIONS UNSTABLE. PROPERLY
SUPPORT (Fig. 6) OR SECURE VEHICLE TO HOIST-
ING DEVICE WHEN THESE CONDITIONS EXIST.
FLOOR JACK
When properly positioned, a floor jack can be used
to lift a vehicle (Fig. 7). Support the vehicle in the
raised position with jack stands at the front and rear
ends of the frame rails (Fig. 6).
CAUTION: Do not lift vehicle with a floor jack posi-
tioned under:
²An axle tube.
²A body side sill.
²A steering linkage component.
²A drive shaft.
²The engine or transmission oil pan.
²The fuel tank.
²A front suspension arm.NOTE: Use the correct frame rail lifting locations
only (Fig. 8) and (Fig. 9).
HOIST
A vehicle can be lifted with:
²A single-post, frame-contact hoist.
²A twin-post, chassis hoist.
²A ramp-type, drive-on hoist.
NOTE: When a frame-contact type hoist is used,
verify that the lifting pads are positioned properly
(Fig. 7). The forward lifting pads should be posi-
tioned against the forward flange of the transmis-
sion crossmember brackets at the bottom of the
frame rail (Fig. 8). The real lifting pads should be
wedged between the forward flange of the leaf
spring bracket and the frame rail (Fig. 9). Safety
stands should be placed under the frame rails at
the front and rear ends (Fig. 6).
Fig. 6 Safety Stands
1 - SAFETY STANDS
0 - 20 LUBRICATION & MAINTENANCEDR
JUMP STARTING (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)

To adjust the vehicle height turn the torsion bar
adjustment bolt CLOCKWISE to raise the vehicle
and COUNTER CLOCKWISE to lower the vehicle.
CAUTION: ALWAYS raise the vehicle to the correct
suspension height, NEVER lower the vehicle to
obtain the correct suspension height. If the vehicle
suspension height is too high, lower the vehicle
below the height specification. Then raise the vehi-
cle to the correct suspension height specification.
This will insure the vehicle maintains the proper
suspension height.
NOTE: If a height adjustment has been made, per-
form height measurement again on both sides of
the vehicle.
STANDARD PROCEDURE - CAMBER AND
CASTER ADJUSTMENT
NOTE: 4X4 (LD) SUSPENSION HEIGHT MEASURE-
MENT MUST BE PERFORMED BEFORE AN ALIGN-
MENT.
NOTE: When the upper control arm pivot bolts are
loosened the upper control arm will normally go
inwards toward the frame automatically with the
weight of the vehicle.
Camber and caster angle adjustments involve
changing the position of the upper control arm incon-
junction with the slotted holes in the frame brackets,
Install special tool 8876 between the top of the upper
control arm bracket and the upper control arm (on
1500 series 4X2 & 4X4). Install special tool 8876
between the bottom of the upper control arm bracket
pressing the tool against the frame and the upper
control arm (on 2500/3500 series 4X2) in order to
move the upper control arm outwards for proper
adjustment with the vehicle at normal ride height
(Fig. 3).
STANDARD PROCEDURE - TOE ADJUSTMENT
4X4 SUSPENSION HEIGHT MESUREMENT
MUST BE PERFORMED BEFORE AN ALIGN-
MENT.
The wheel toe position adjustment is the final
adjustment.
(1) Start the engine and turn wheels both ways
before straightening the wheels. Secure the steering
wheel with the front wheels in the straight-ahead
position.
(2) Loosen the tie rod jam nuts.NOTE: Each front wheel should be adjusted for
one-half of the total toe position specification. This
will ensure the steering wheel will be centered
when the wheels are positioned straight-ahead.
(3) Adjust the wheel toe position by turning the
inner tie rod as necessary (Fig. 4).
(4) Tighten the tie rod jam nut to 75 N´m (55 ft.
lbs.).
(5) Verify the specifications
(6) Turn off engine.
STANDARD PROCEDURE - CAMBER, CASTER
AND TOE ADJUSTMENT
NOTE: 4X4 (LD) SUSPENSION HEIGHT MEASURE-
MENT MUST BE PERFORMED BEFORE AN ALIGN-
MENT.
Camber and caster angle adjustments involve
changing the position of the upper control arm with
the slots in the frame brackets using special tool
8876 to move the upper control arm outwards for
proper adjustment. (Fig. 3)
NOTE: When the upper control arm pivot bolts are
loosened the upper control arm will normally go
inwards toward the frame automatically with the
weight of the vehicle.
CASTER
Moving the front or rear position of the upper con-
trol arm in or out, will change the caster angle and
camber angle significantly. To maintain the camber
Fig. 3 CASTER & CAMBER ADJUSTMENT
1 - FRONT PIVOT BOLT
2 - REAR PIVOT BOLT
3 - SLOTTED HOLES FOR ADJUSTMENT OF CASTER &
CAMBER
4 - UPPER CONTROL ARM
2 - 4 WHEEL ALIGNMENTDR
WHEEL ALIGNMENT (Continued)

angle while adjusting caster, move one pivot bolt of
the upper control arm in or out. Then move the other
pivot bolt of the upper control arm in the opposite
direction. Install special tool 8876 between the top of
the upper control arm bracket and the upper control
arm (on 1500 series 4X2 & 4X4). Install special tool
8876 between the bottom of the upper control arm
bracket pressing the tool against the frame and the
upper control arm (on 2500/3500 series 4X2) in order
to move the upper control arm outwards for proper
adjustment with the vehicle at normal ride height
(Fig. 3).
To increase positive caster angle, move the rear
position of the upper control arm inward (toward the
engine). Move the front of the upper control arm out-
ward (away from the engine) slightly until the origi-
nal camber angle is obtained using special tool 8876
to move the upper control arm for proper adjustment.
(Fig. 3)
CAMBER
Move both pivot bolts of the upper control arm
together in or out. This will change the camber angle
significantly and little effect on the caster angle
using special tool 8876 to move the upper control
arm for proper adjustment. (Fig. 3)
After adjustment is made tighten the upper control
arm nuts to proper torque specification.
TOE ADJUSTMENT
The wheel toe position adjustment is the final
adjustment.
(1) Start the engine and turn wheels both ways
before straightening the wheels. Secure the steering
wheel with the front wheels in the straight-ahead
position.
(2) Loosen the tie rod jam nuts.
NOTE: Each front wheel should be adjusted for
one-half of the total toe position specification. This
will ensure the steering wheel will be centered
when the wheels are positioned straight-ahead.
(3) Adjust the wheel toe position by turning the
inner tie rod as necessary (Fig. 4).
(4) Tighten the tie rod jam nut to 75 N´m (55 ft.
lbs.).
(5) Verify the specifications
(6) Turn off engine.
STANDARD PROCEDURE - ALIGNMENT
LINK/COIL SUSPENSION
Before each alignment reading the vehicle should
be jounced (rear first, then front). Grasp each
bumper at the center and jounce the vehicle up and
down several times. Always release the bumper inthe down position.Set the front end alignment to
specifications while the vehicle is in its NOR-
MALLY LOADED CONDITION.
CAMBER:The wheel camber angle is preset and
is not adjustable.
CASTER:Check the caster of the front axle for
correct angle. Be sure the axle is not bent or twisted.
Road test the vehicle and make left and right turn.
Observe the steering wheel return-to-center position.
Low caster will cause poor steering wheel returnabil-
ity.
Caster can be adjusted by rotating the cams on the
lower suspension arm (Fig. 5).
TOE POSITION:The wheel toe position adjust-
ment should be the final adjustment.
Fig. 4 TIE ROD END
1 - JAM NUT
2 - TIE ROD - INNER
3 - TIE ROD END - OUTER
Fig. 5 ALIGNMENT ADJUSTMENT CAM
1 - BRACKET REINFORCEMENT
2 - ADJUSTING BOLT
3 - ADJUSTMENT CAM
DRWHEEL ALIGNMENT 2 - 5
WHEEL ALIGNMENT (Continued)

(1) Start the engine and turn wheels both ways
before straightening the wheels. Center and Secure
the steering wheel and turn off engine.
(2) Loosen the adjustment sleeve clamp bolts.
(3) Adjust the right wheel toe position with the
drag link. Turn the sleeve until the right wheel is at
the correct TOE-IN position. Position clamp bolts to
their original position and tighten to specifications.
Make sure the toe setting does not change dur-
ing clamp tightening.
(4) Adjust left wheel toe position with tie rod at
left knuckle. Turn the sleeve until the left wheel is at
the correct TOE-IN position. Position clamp bolts to
their original position and tighten to specifications.
Make sure the toe setting does not change dur-
ing clamp tightening.
(5) Verify the right toe setting and a straight steer-
ing wheel.
(6) Road test the vehicle.
SPECIFICATIONS
ALIGNMENT
NOTE: All alignment specifications are in degrees.
SPECIFICATIONS
DESCRIP-
TIONSPECIFICATION
VEHICLE
1500WHEEL
BASECASTER
(4.0É
Min,
+.75É
Max)CAMBER
(  .50É)TOTAL
TOE-IN
(  .10É)
4X2 120.5 in 4.0É .0É .10É
4X2 140.5 in 4.2É .0É .10É
4X2 160.5 in 4.4É .0É .10É
VEHICLE
1500WHEEL
BASECASTER
(4.0É
Min,
+.75É
Min)CAMBER
( .50É)TOTAL
TOE-IN
( .10É)
4X4 120.5 in 4.2É .0É .10É
4X4 140.5 in 4.4É .0É .10É
4X4 160.5 in 4.6É .0É .10É
MAX
RT/LT
DIF-
FERENCE
4X2
1500Ð .40É .50É 0.06É
DESCRIP-
TIONSPECIFICATION
MAX
RT/LT
DIF-
FERENCE
4X4
1500Ð .40É .60É 0.06É
VEHICLE
4X2
2500 &
3500WHEEL
BASECASTER
(3.55É
Min,
+.75É
Max)CAMBER
( .50É)TOTAL
TOE-IN
(0.20É
 .10É)
4X2
2500&3500140 4.0É 0.0É .10É  
.05É
4X2
2500&3500160 4.3É 0.0É .10É  
.05É
MAX
RT/LT
DIF-
FERENCE
4X2
2500&3500Ð  0.4É  0.6É 0.1É
VEHICLE
4X4
2500&3500WHEEL
BASECASTER
(4.0É
Min,
+.75É
Max)CAMBER
(.25É
 .5É)TOTAL
TOE-IN
(0.20É
 .10É)
4X4
2500&3500140 4.5É .25É .10É  
.05É
4X4
2500&3500160 4.7É .25É .10É  
.05É
MAX
RT/LT
DIF-
FERENCE
4X4
2500&3500Ð  .5É  .5É 0.1É
DESCRIP-
TIONREAR SPECIFICATION
CAMBER
(-.10É   0.35É)TOTAL TOE-IN
(0.30É   0.35É)
THRUST ANGLE 0É   0.4É
4X2
4X4
1500
THRUST ANGLE -0.2É   0.2É
4X2
4X4
2500&3500
2 - 6 WHEEL ALIGNMENTDR
WHEEL ALIGNMENT (Continued)

BUSHINGS
REMOVAL
REMOVAL - LOWER CONTROL ARM
BUSHINGS - 4WD (LD)
(1) Remove the lower control arm (Refer to 2 -
SUSPENSION/FRONT/LOWER CONTROL ARM -
REMOVAL).
(2) Secure the control arm in a vise.
NOTE: Extreme pressure lubrication must be used
on the threaded portions of the tool. This will
increase the longevity of the tool and insure proper
operation during the removal and installation pro-
cess.
FRAME MOUNTED BUSHING
(1) Install the bushing tool 8682-3 (receiver) and
8682-4 (driver) with the threaded rod and the two
bearings as shown for the replacement of the frame
bushing (Fig. 3)
CONTROL ARM BUSHING
(1) Install bushing remover tools 8682-2 (adapter),
8682-3 (receiver) and 8682-4 (driver) with the
threaded rod and the two bearings as shown (Fig. 4)
REMOVAL - TORSION BAR CROSSMEMBER
BUSHING
(1) Remove the torsion bar cross member (Refer to
13 - FRAME & BUMPERS/FRAME/REAR CROSS-
MEMBER - REMOVAL).
(2) Secure the cross member in a vise.
NOTE: Extreme pressure lubrication must be used
on the threaded portions of the tool. This will
increase the longevity of the tool and insure proper
operation during the removal and installation pro-
cess.
(3) Install special tools 8838 threaded rod, 8835-1,
8835-4 and 8835-3 as shown in the graphic below
(Fig. 5).
(4) Press out the bushing.
REMOVAL - LOWER CONTROL ARM
BUSHINGS - 2WD (LD)
NOTE: HD 4X2 bushings are not servicable.
(1) Remove the lower control arm (Refer to 2 -
SUSPENSION/FRONT/LOWER CONTROL ARM -
REMOVAL).
(2) Secure the control arm in a vise.
NOTE: Extreme pressure lubrication must be used
on the threaded portions of the tool. This will
increase the longevity of the tool and insure proper
operation during the removal and installation pro-
cess.
Fig. 3 FRAME BUSHING REMOVAL
1 - THREADED ROD
2 - BEARINGS
3 - 8682-3 (RECEIVER)
4 - FRAME
5 - 8682-4 (DRIVER)
6 - NUT
7 - BUSHING
Fig. 4 CONTROL ARM BUSHING REMOVAL
1 - 8682-4 (DRIVER)
2 - BUSHING
3 - LOWER CONTROL ARM
4 - 8682-2 (ADAPTER)
5 - 8682-3 (RECEIVER)
6 - BEARING
7 - THREADED ROD
DRFRONT - INDEPENDENT FRONT SUSPENSION 2 - 13

BUSHINGS
REMOVAL
(1) Remove the spring from the vehicle.
(2) Make small relief cuts in the flared up end of
the bushing metal being careful not to cut the spring.
Use a punch to bend the flared bushing metal down
for push out.
(3) Position the spring eye in a press.
(4) Press the bushing out with an appropriate size
driver.
INSTALLATION
(1) Press new bushing into the spring eye with an
appropriate size driver. The bushing should be cen-
tered in the spring eye.
(2) Stake the outermetal of the bushing in a mini-
mum of six points to retain the bushing.
(3) Install the spring on the vehicle.
JOUNCE BUMPER
REMOVAL
(1) Remove the two bolts securing the jounce
bumper to the bracket (Fig. 1).
(2) Remove the jounce bumper.
INSTALLATION
(1) Install the jounce bumper.
(2) Install the two bolts securing the jounce
bumper to the bracket. Tighten the bolts to 40 N´m
(30 ft. lbs.)(LD) or Tighten the bolts to 61 N´m (45 ft.
lbs.)(HD).
AUXILIARY SPRING BUMPERS
(3500)
REMOVAL
(1) Remove the nut securing the auxiliary spring
bumper to the bracket (Fig. 2).
(2) Remove the auxiliary spring bumper.
INSTALLATION
(1) Install the auxiliary spring bumper.
(2) Install the nut securing the auxiliary spring
bumper to the bracket (Fig. 2). Tighten the nut to 25
N´m (34 ft. lbs.).
SHOCK
REMOVAL
(1) Raise vehicle and support the axle.
NOTE: The rear upper shock attachment uses a flag
nut. Do not use an air tool to remove the bolt, the
flag may rotate into the bottom of the bed and
cause damage. Use a wrench to hold the nut when
loosening.
(2) Remove the upper shock bolt and nut (Fig. 3).
(3) Remove the lower shock bolt and nut.
(4) Remove the rear shock absorber from the vehi-
cle.
INSTALLATION
(1) Position the shock absorber in the brackets.
(2) Install the bolts through the brackets and the
shock. Install the flag nut on the top bolt and nut on
lower bolt.
Fig. 1 JOUNCE BUMPER
1 - MOUNTING BOLTS
2 - JOUNCE BUMPER
Fig. 2 AUXILIARY SPRING BUMPER (3500)
1 - NUTS
2 - AUXILIARY SPRING BUMPERS
DRREAR 2 - 43