1998 DODGE RAM 1500 Coil

LOWER SUSPENSION ARM
REMOVAL
(1) Raise and support the vehicle.
(2) Paint or scribe alignment marks on the cam
adjusters and suspension arm for installation refer-
ence (Fig. 22).
(3) Remove the lower suspension arm nut, cam
and cam bolt from the axle.
(4) Remove the nut and bolt from the frame rail
bracket and remove the lower suspension arm (Fig.
22).
INSTALLATION
(1) Position the lower suspension arm at the axle
bracket and frame rail bracket.
(2) Install the rear bolt and finger tighten the nut.
(3) Install the cam bolt, cam and nut in the axle
and align the reference marks.
(4) Remove support and lower the vehicle.
(5) Tighten cam nut at the axle bracket to 217
N´m (160 ft. lbs.). Tighten rear nut at the frame
bracket to 217 N´m (160 ft. lbs.).
SHOCK
DIAGNOSIS AND TESTING - SHOCK
A knocking or rattling noise from a shock absorber
may be caused by movement between mounting
bushings and metal brackets or attaching compo-
nents. These noises can usually be stopped by tight-
ening the attaching nuts. If the noise persists,
inspect for damaged and worn bushings, and attach-
ing components. Repair as necessary if any of these
conditions exist.
A squeaking noise from the shock absorber may be
caused by the hydraulic valving and may be intermit-
tent. This condition is not repairable and the shock
absorber must be replaced.
The shock absorbers are not refillable or adjust-
able. If a malfunction occurs, the shock absorber
must be replaced. To test a shock absorber, hold it in
an upright position and force the piston in and out of
the cylinder four or five times. The action throughout
each stroke should be smooth and even.
The shock absorber bushings do not require any
type of lubrication. Do not attempt to stop bushing
noise by lubricating them. Grease and mineral oil-
base lubricants will deteriorate the bushing.
REMOVAL
(1) Remove the nut, retainer and grommet from
the upper stud in the engine compartment.
(2) Remove three nuts from the upper shock
bracket (Fig. 23).
(3) Remove the lower bolt from the axle bracket
(Fig. 24). Remove the shock absorber from engine
compartment.
INSTALLATION
(1) Position the lower retainer and grommet on the
upper stud. Insert the shock absorber through the
spring from engine compartment.
(2) Install the lower bolt and tighten to 135 N´m
(100 ft. lbs.).
(3) Install the upper shock bracket and three nuts.
Tighten nuts to 75 N´m (55 ft. lbs.).
(4) Install upper grommet and retainer. Install
upper shock nut and tighten to 54 N´m (40 ft. lbs).
Fig. 22 Adjustment Cam
1 - ADJUSTMENT CAM
2 - AXLE BRACKET
3 - BRACKET REINFORCEMENT
4 - LOWER SUSPENSION ARM
2 - 38 FRONT - LINK/COILDR

SPRING
REMOVAL
(1) Raise and support the vehicle. Position a
hydraulic jack under the axle to support it.
(2) Paint or scribe alignment marks on lower sus-
pension arm cam adjusters and axle bracket for
installation reference.
(3) Remove the upper suspension arm and loosen
lower suspension arm bolts.
(4) Mark and disconnect the front propeller shaft
from the axle 4x4 models.
(5) Disconnect the track bar from the frame rail
bracket.
(6) Disconnect the drag link from pitman arm.
(7) Disconnect the stabilizer bar link and shock
absorber from the axle.
(8) Lower the axle until the spring is free from the
upper mount. Remove the coil spring.
INSTALLATION
(1) Position the coil spring on the axle pad.
(2) Raise the axle into position until the spring
seats in the upper mount.
(3) Connect the stabilizer bar links and shock
absorbers to the axle bracket. Connect the track bar
to the frame rail bracket.
(4) Install the upper suspension arm.
(5) Install the front propeller shaft to the axle 4x4
model.
(6) Install drag link to pitman arm and tighten
nut to specifications. Install new cotter pin.
(7) Remove the supports and lower the vehicle.
(8) Tighten the following suspension components
to specifications:
²Link to stabilizer bar nut.
²Lower shock bolt.
²Track bar bolt at axle shaft tube bracket.
²Upper suspension arm nut at axle bracket.
²Upper suspension nut at frame bracket.
²Align lower suspension arm reference marks and
tighten cam nut.
²Lower suspension nut at frame bracket.
STABILIZER BAR
REMOVAL
(1) Raise and support the vehicle.
(2) Hold the stabilizer link shafts with a wrench
and remove the link nuts at the stabilizer bar.
(3) Remove the retainers and grommets from the
stabilizer bar links.
(4) Remove the stabilizer bar link nuts from the
axle brackets.
Fig. 23 Shock Absorber and Bracket
1 - GROMMET
2 - RETAINER
3 - BRACKET
4 - RETAINER
5 - SHOCK
6 - GROMMET
Fig. 24 Shock Absorber Axle Mount
1 - SHOCK
2 - SPRING
3 - FLAG NUT
4 - SHOCK BOLT
DRFRONT - LINK/COIL 2 - 39
SHOCK (Continued)

(5) Remove the links from the axle brackets with
Puller C-3894-A (Fig. 25).
(6) Remove the stabilizer bar clamps from the
frame rails and remove the stabilizer bar.INSTALLATION
(1) Position the stabilizer bar on the frame rail
and install the clamps and bolts. Ensure the bar is
centered with equal spacing on both sides.
(2) Tighten the clamp bolts to 61 N´m (45 ft. lbs.).
(3) Install links to the axle bracket and tighten
nut to 71 N´m (52 ft. lbs.).
(4) Install links, retainers, grommets and nuts to
the stabilizer bar. Hold the link shaft with a wrench
and tighten the nuts to 37 N´m (27 ft. lbs.).
(5) Remove the supports and lower the vehicle.
Fig. 25 Stabilizer Link
1 - PULLER
2 - LINK
2 - 40 FRONT - LINK/COILDR
STABILIZER BAR (Continued)

(12) Remove upper and lower suspension arms
from the axle bracket (Fig. 5).
(13) Lower the axle. The coil springs will drop
with the axle.
(14) Remove coil springs from the axle bracket.
INSTALLATION
CAUTION: Suspension components with rubber
bushings should be tightened with the weight of thevehicle on the suspension. Failure to heed caution
may result in damage.
(1) Support the axle on a suitable lifting device.
(2) Secure axle to lifting device.
(3) Position the axle under the vehicle.
(4) Install springs, retainer clip and bolts.
(5) Raise axle and align it with the spring pads.
(6) Position upper and lower suspension arms in
the axle brackets. Install bolts, nuts and align the
suspension alignment cams to the reference marks.
Do not tighten at this time.
Fig. 2 SHOCK ABSORBER
1 - SHOCK
2 - SPRING
3 - FLAG NUT
4 - SHOCK BOLT
Fig. 3 TRACK BAR
1 - TRACK BAR
2 - BOLT
3 - NUT
Fig. 4 DRAG LINK
1 - PITMAN ARM
2 - DRAGLINK
3 - PULLER C-3894-A
Fig. 5 LINK/COIL SUSPENSION
1 - STABILIZER BAR
2 - SHOCK ABSORBER
3 - COIL SPRING
4 - UPPER SUSPENSION ARM
5 - LOWER SUSPENSION ARM
6 - TRACK BAR
3 - 58 FRONT AXLE - 9 1/4 AADR
FRONT AXLE - 9 1/4 AA (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

INSTALLATION
(1) Install tensioner on to the mounting bracket.
Tighten bolt to 41 N´m (30 ft. lbs.).
(2) Install tensioner and bracket assembly
(3) Install accessory drive belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
BELT TENSIONER - 5.9L
DIESEL
DESCRIPTION
Drive belts on all engines are equipped with a
spring loaded automatic belt tensioner (Fig. 4). This
tensioner maintains constant belt tension at all times
and requires no maintenance or adjustment.
CAUTION: Do not attempt to check belt tension with
a belt tension gauge on vehicles equipped with an
automatic belt tensioner.
OPERATION
WARNING: THE AUTOMATIC BELT TENSIONER
ASSEMBLY IS SPRING LOADED. DO NOT ATTEMPT
TO DISASSEMBLE THE TENSIONER ASSEMBLY.
The automatic belt tensioner maintains correct belt
tension using a coiled spring within the tensioner
housing. The spring applies pressure to the tensioner
arm pressing the arm into the belt, tensioning the
belt.
REMOVAL
WARNING: BECAUSE OF HIGH SPRING PRES-
SURE, DO NOT ATTEMPT TO DISASSEMBLE AUTO-
MATIC TENSIONER. UNIT IS SERVICED AS AN
ASSEMBLY.
(1) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(2) Remove tensioner mounting bolt (Fig. 5) and
remove tensioner.
Fig. 4 Accessory Drive Belt - 5.9L Diesel
1 - GENERATOR
2 - WATER PUMP
3 - IDLER
4 - POWER STEERING PUMP
5 - RADIATOR FAN PULLEY
6 - CRANKSHAFT
7 - AUTOMATIC TENSIONER
8 - A/C COMPRESSOR
Fig. 5 AUTOMATIC BELT TENSIONER 5.9L DIESEL
ENGINE
1 - GENERATOR
2 - WATER PUMP
3 - IDLER
4 - POWER STEERING PUMP
5 - RADIATOR FAN PULLEY
6 - CRANKSHAFT
7 - AUTOMATIC TENSIONER
8 - A/C COMPRESSOR
DRACCESSORY DRIVE 7 - 23
BELT TENSIONER-5.7L (Continued)

REMOVAL
(1) Disconnect the battery negative cable.
(2) Drain the coolant (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(3) Remove the power cord from the heater by
unplugging (Fig. 7).
(4) Loosen (but do not completely remove) the
screw at center of block heater (Fig. 7).
(5) Remove the block heater by carefully prying
from side-to-side. Note the direction of the heating
element coil (up or down). The element coil must be
installed correctly to prevent damage.
INSTALLATION
(1) Clean and inspect the block heater hole.
(2) Install the new O-ring seal(s) to heater.
(3) Insert the block heater into cylinder block and
position the element properly.
(4) With the heater fully seated, tighten center
screw to 2 N´m (17 in. lbs.).
(5) Fill the cooling system with the recommended
coolant. (Refer to 7 - COOLING - STANDARD PRO-
CEDURE).
(6) Start and warm the engine.
(7) Check the block heater for leaks.
ENGINE BLOCK HEATER - 5.9L
DIESEL
DESCRIPTION
WARNING: DO NOT OPERATE ENGINE UNLESS
BLOCK HEATER CORD HAS BEEN DISCONNECTED
FROM POWER SOURCE AND SECURED IN PLACE.
THE POWER CORD MUST BE SECURED IN ITS
RETAINING CLIPS AND ROUTED AWAY FROM
EXHAUST MANIFOLDS AND MOVING PARTS.
An optional engine block heater is available on all
models. The heater is equipped with a power cord.
The heater is mounted in a threaded hole of the
engine cylinder block with the heating element
immersed in engine coolant. The cord is attached to
an engine compartment component with tie-straps.
The 5.9L diesel engine has the block heater located
on the right side of the engine below the exhaust
manifold next to the oil cooler (Fig. 8).
Fig. 6 Engine Block Heater - 3.7L/4.7L
1 - ENGINE BLOCK HEATER
Fig. 7 Engine Block Heater
1 - FREEZE PLUG HOLE
2 - BLOCK HEATER
3 - SCREW
4 - POWER CORD (120V AC)
5 - HEATING COIL
6 - OIL FILTER
DRENGINE 7 - 37
ENGINE BLOCK HEATER (Continued)

(9) Install support rod.
(10) Fill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(11) Connect negative battery cable to battery.
(12) Start and warm engine. Check for leaks.
FAN DRIVE VISCOUS CLUTCH-
GAS ENGINES
DESCRIPTION
The thermal viscous fan drive (Fig. 31) is a sili-
cone-fluid- filled coupling used to connect the fan
blades to the water pump shaft. The coupling allows
the fan to be driven in a normal manner. This is
done at low engine speeds while limiting the top
speed of the fan to a predetermined maximum level
at higher engine speeds.
OPERATION
A thermostatic bimetallic spring coil is located on
the front face of the viscous fan drive unit (a typical
viscous unit is shown in (Fig. 32). This spring coilreacts to the temperature of the radiator discharge
air. It engages the viscous fan drive for higher fan
speed if the air temperature from the radiator rises
above a certain point. Until additional engine cooling
is necessary, the fan will remain at a reduced rpm
regardless of engine speed.
Only when sufficient heat is present, will the vis-
cous fan drive engage. This is when the air flowing
through the radiator core causes a reaction to the
bimetallic coil. It then increases fan speed to provide
the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge
temperature will drop. The bimetallic coil again
reacts and the fan speed is reduced to the previous
disengaged speed.
DIAGNOSIS AND TESTING - VISCOUS FAN
DRIVE
NOISE
NOTE: It is normal for fan noise to be louder (roar-
ing) when:
²The underhood temperature is above the engage-
ment point for the viscous drive coupling. This may
occur when ambient (outside air temperature) is very
high.
Fig. 30 Thermostat - 8.0L V-10 Engine
1 - COOLANT TEMP. SENSOR (FOR PCM)
2 - HEATER SUPPLY FITTING
3 - BOLTS (6)
4 - HOUSING WITH INTEGRAL SEAL
5 - THERMOSTAT
6 - RUBBER LIP SEAL
7 - TEMP. GAUGE SENDING UNIT
Fig. 31 Viscous Fan
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
5 - Bolts (4)
7 - 50 ENGINEDR
ENGINE COOLANT THERMOSTAT - 8.0L (Continued)