During antilock braking, the solenoid valves are
opened and closed as needed. The valves are not
static. They are cycled rapidly and continuously to
modulate pressure and control wheel slip and decel-
eration.
During antilock braking, solenoid valve pressure
modulation occurs in three stages, pressure decrease,
pressure hold, and pressure increase. The valves are
all contained in the valve body portion of the HCU.
PRESSURE DECREASE
The inlet valve is closed and the outlet valve is
opened during the pressure decrease cycle.
A pressure decrease cycle is initiated when speed
sensor signals indicate high wheel slip at one or
more wheels. At this point, the CAB closes the inlet
to prevent the driver from further increasing the
brake pressure and locking the brakes. The CAB
then opens the outlet valve, which also opens the
return circuit to the accumulators. Fluid pressure is
allowed to bleed off (decrease) as needed to prevent
wheel lock.
Once the period of high wheel slip has ended, the
CAB closes the outlet valve and begins a pressure
increase or hold cycle as needed.
PRESSURE HOLD
Both solenoid valves are closed in the pressure
hold cycle. Fluid apply pressure in the control chan-
nel is maintained at a constant rate. The CAB main-
tains the hold cycle until sensor inputs indicate a
pressure change is necessary.
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 counteract unequal
wheel speeds. This cycle controls re-application of
fluid apply pressure due to changing road surfaces or
wheel speed.
REMOVAL
(1) Disconnect battery negative cable.
(2) Push the harness connector locks to release the
locks, then remove the connectors from the CAB.
(3) Disconnect brake lines from HCU (Fig. 7).
(4) Remove the two mounting bolts on either side
of the assembly which attach the assembly to the
mounting bracket.
(5) Tilt the assembly upward were the brake lines
attach and remove the assembly from the mounting
bracket.
INSTALLATION
(1) Install the assembly into the mounting bracket.
(2) Install the mounting bolts and tighten to 12
N´m (102 in. lbs.).
(3) Connect the CAB harnesses.
(4) Connect the brake lines to the HCU. Tighten
brake line fittings to 19-23 N´m (170-200 in. lbs.).
(5) Connect battery.
(6) Bleed brake system, (Refer to 5 - BRAKES -
STANDARD PROCEDURE).
Fig. 7 Brake Lines
1 - BRAKE LINES
2 - HCU
BR/BEBRAKES - ABS 5 - 41
HCU (HYDRAULIC CONTROL UNIT) (Continued)
SPECIFICATIONS - CLUTCH
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Nut, slave cylinder 19-26 14-19 170-230
Bolt, clutch cover-5/16 in. 23 17 -
Bolt, clutch cover-3/8 in. 41 30 -
Pivot, release bearing 23 17 -
Screw, fluid reservoir 5 - 40
CLUTCH DISC
REMOVAL
(1) Raise and support vehicle.
(2) Support engine with wood block and adjustable
jack stand, so engine mounts are not strained (Fig.
4).
(3) Remove transmission and transfer case, if
equipped. Refer to 21 Transmission and Transfer
Case for procedures.(4) If pressure plate will be reused, mark position
of cover on flywheel with paint or scriber (Fig. 5).
(5) Insert clutch alignment tool through clutch disc
and into pilot bushing, to hold disc in place.
Fig. 4 Supporting Engine -Diesel Model Shown
1 - WOOD BLOCK
2 - ADJUSTABLE JACK STAND
Fig. 5 Marking Pressure Plate Position
1 - FLYWHEEL
2 - ALIGNMENT MARKS
3 - PRESSURE PLATE
BR/BECLUTCH 6 - 7
CLUTCH (Continued)
(3) Replace one of the flywheel bolts with an
appropriate size threaded rod that is 10 in. (25.4 cm)
long (Fig. 11). The rod will be used to mount the dial
indicator.
(4) Remove release fork from the clutch housing.
(5) Install clutch housing. Tighten the housing
bolts nearest the alignment dowels first.
(6) Mount dial indicator on the threaded rod and
position indicator plunger on the clutch housing bore
(Fig. 12).
(7) Rotate crankshaft until indicator plunger is at
the topof the housing bore. Zero the indicator at this
point.(8) Rotate crankshaft and record indicator read-
ings at eight points (45É apart) around the bore (Fig.
13). Take measurement at least twice for accuracy.
(9) Subtract each reading from the one 180É oppo-
site to determine runout and direction. Bore runout
example (Fig. 13):
²0.000 ± (±0.007) = 0.007 in.
²+0.002 ± (±0.010) = 0.012 in.
²+0.004 ± (±0.005) = 0.009 in.
²±0.001 ± (+0.001) = ±0.002 in.
In this example the largest or total indicator read-
ing (TIR) difference is 0.012 inch. This means the
housing bore is offset from the crankshaft centerline
by 0.006 in. which is 1/2 of 0.012 inch. The dowels
needed to correct this have an offset of 0.007 in. (Fig.
14).
Remove housing and install dowels with the slotted
side facing out so they can be turned with a screw-
driver. Then install the housing and mount the dial
indicator and check bore runout again. Rotate the
dowels until the TIR is less than 0.010 inch.
Clutch Housing Face Runout
(1) Position dial indicator towards the housing face
(Fig. 15) with indicator plunger on the rim of the
housing bore.
(2) Rotate crankshaft until indicator plunger is at
the 10 O'clock position and zero the dial indicator.
(3) Measure and record face runout readings at
four points 90É apart (Fig. 16). Take measurement at
least twice for accuracy.
(4) Subtract lowest reading from highest to deter-
mine total runout. If low reading wasminus0.004
in. and highest reading wasplus0.009 in. the total
runout is 0.013 inch.
NOTE: Maximum acceptable face runout is 0.010
inch.
Fig. 11 Dial Indicator Mounting Stud Or Rod
1 - 7/16 - 20 THREAD
2 - NUT
3 - STUD OR THREADED ROD
4 - 10 INCHES LONG
Fig. 12 CLUTCH HOUSING BORE RUNOUT
1 - MOUNTING STUD OR ROD
2 - DIAL INDICATOR
3 - INDICATOR PLUNGER
4 - CLUTCH HOUSING BORE
Fig. 13 MEASUREMENT POINTS AND READINGS
1 - CLUTCH HOUSING BORE CIRCLE
6 - 10 CLUTCHBR/BE
CLUTCH HOUSING (Continued)
To correct this example (Fig. 16) the shims needed
between the clutch housing and transmission are:
²0.009 in. at the 0.000 corner
²0.012 in. at the ±0.003 corner
²0.013 in. at the ±0.004 corner
After installing the clutch assembly and housing,
tighten the housing bolts nearest the alignment dow-
els first.NOTE: Shims can be made from shim stock or sim-
ilar materials of the required thickness (Fig. 17).
REMOVAL
(1) Raise and support vehicle.
(2) Remove transmission and transfer case, if
equipped. Refer to 21 Transmission and Transfer
Case for proper procedures.
(3) Remove the starter from the clutch housing.
(4) Remove the clutch housing dust shield from the
clutch housing.
(5) Remove clutch housing bolts and remove hous-
ing from engine (Fig. 18) and (Fig. 19).
INSTALLATION
(1) Clean housing mounting surface of engine
block with wax and grease remover.
(2) Verify that clutch housing alignment dowels
are in good condition and properly seated.
Fig. 14 Housing Bore Alignment Dowel Selection
1 - SLOT DIRECTION OF OFFSET
2 - OFFSET DOWEL
TIR VALUE OFFSET DOWEL REQUIRED
0.011 - 0.021 inch 0.007 inch
0.022 - 0.035 inch 0.014 inch
0.036 - 0.052 inch 0.021 inch
Fig. 15 DIAL INDICATOR LOCATION
1 - INDICATOR PLUNGER
2 - DIAL INDICATOR
3 - CLUTCH HOUSING FACE
4 - INDICATOR MOUNTING STUD OR ROD
Fig. 16 MEASUREMENT POINTS AND READINGS
1 - CLUTCH HOUSING FACE CIRCLE (AT RIM OF BORE)
Fig. 17 ALIGNMENT SHIMS
1 - CUT/DRILL BOLT HOLE TO SIZE
2 - SHIM STOCK
3 - MAKE SHIM 1-INCH DIAMETER
BR/BECLUTCH 6 - 11
CLUTCH HOUSING (Continued)
(3) Transfer slave cylinder, release fork and boot,
fork pivot stud and wire/hose brackets to new hous-
ing.
(4) Lubricate release fork and pivot contact sur-
faces with Mopar High Temperature wheel bearing
grease or equivalent before installation.
(5) Align and install clutch housing on transmis-
sion (Fig. 19). Tighten housing bolts closest to align-
ment dowels first and to the following torque values:
²1/4in. diameter ªAº bolts - 4.5 N´m (40 in.lb.).
²3/8in. diameter ªAº bolts - 47.5 N´m (35 ft.lb.).
²7/16in. diameter ªAº bolts - 68 N´m (50 ft.lb.).
²ªBº bolts for 5.2L/5.9L applications - 41 N´m (30
ft.lb.).
²ªBº bolts for 5.9L TD/8.0L applications - 47.5
N´m (35 ft.lb.).
²ªCº bolts for 5.2/5.9L applications - 68 N´m (50
ft.lb.).
²ªCº bolts for 5.9L TD applications - 47.5 N´m (35
ft.lb.).
²ªCº bolts for 8.0L applications - 74.5 N´m (55
ft.lb.).
(6) Install transmission-to-engine strut after
installing clutch housing. Tighten bolt attaching
strut to clutch housing first and engine bolt last.
(7) Install the starter to the clutch housing.
(8) Install the clutch housing dust shield to the
clutch housing. Tighten the bolts to
(9) Install transmission and transfer case, if
equipped. Refer to 21Transmission and Transfer Case
for proper procedures.
CLUTCH RELEASE BEARING
REMOVAL
(1) Remove transmission and transfer case, if
equipped. Refer to 21 Transmission and Transfer
Case forprocedures.
(2) Remove clutch housing, for NV4500 equipped
vehicles.
(3) Disconnect release bearing from release fork
and remove bearing (Fig. 20).
INSTALLATION
NOTE: Inspect bearing slide surface on transmis-
sion front bearing retainer. Replace retainer if slide
surface is scored, worn or cracked. Inspect release
lever and pivot stud. Be sure stud is secure and in
good condition. Be sure fork is not distorted or
worn. Replace fork spring clips if bent or damaged.
(1) Lubricate input shaft splines, bearing retainer
slide surface, lever pivot ball stud and release lever
pivot surface with Mopar high temperature bearing
grease or equilvalent.
Fig. 18 Transmission/Clutch Housing - NV4500
1 - CLUTCH HOUSING
2 - TRANSMISSION
Fig. 19 Clutch Housing Installation - NV4500
1 - ENGINE BLOCK
2 - CLUTCH DISC AND COVER
3 - CLUTCH HOUSING
4 - DUST COVER
6 - 12 CLUTCHBR/BE
CLUTCH HOUSING (Continued)
(2) Install release fork and release bearing (Fig.
21) and verify fork and bearing are secured by spring
clips. Also be sure that the release fork is installed
properly.
NOTE: The rear side of the release lever has one
end with a raised area. This raised area goes
toward the slave cylinder side of the transmission.
(3) Install clutch housing, if removed.(4) Install transmission and transfer case, if
equipped. Refer to 21 Transmission and Transfer
Case for procedures.
FLYWHEEL
DIAGNOSIS AND TESTING - FLYWHEEL
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. Mount the
indicator on a stud installed in place of one of the fly-
wheel bolts.
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 surface grinding equipment.
Remove only enough material to reduce scoring
(approximately 0.001 - 0.003 in.). Heavy stock
removal isnot recommended.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 flywheel 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.
DISASSEMBLY
NOTE: If the teeth are worn or damaged, the fly-
wheel should be replaced as an assembly. This is
the recommended repair. In cases where a new fly-
wheel is not readily available, (V10/Diesel Engine
only) a replacement ring gear can be installed. The
following procedure must be observed to avoid
damaging the flywheel and replacement gear.
WARNING: WEAR PROTECTIVE GOGGLES OR
SAFETY GLASSES WHILE CUTTING RING GEAR.
Fig. 20 Clutch Release Components
1 - CONED WASHER
2 - CLUTCH HOUSING
3 - RELEASE FORK
4 - RELEASE BEARING AND SLEEVE
5 - PIVOT 23 N´m (200 IN. LBS.)
6 - SPRING
Fig. 21 Clutch Release Fork
1 - PIVOT BALL
2 - FORK
3 - SLAVE CYLINDER OPENING
4 - BEARING
BR/BECLUTCH 6 - 13
CLUTCH RELEASE BEARING (Continued)
CLUTCH PEDAL
REMOVAL
(1) Remove knee bolster for access to pedal pivot
shaft.
(2) Remove brake lamp switch.
(3) Remove retaining clips that secure the brake
and clutch pedals to the push rods (Fig. 23).
(4) Remove the brake and clutch master cylinder
pushrods from the pedals.
(5) Remove retainer from passenger side of pedal
pivot shaft (Fig. 24).
(6) Push pedal pivot shaft toward driver side of
support only enough to remove clutch pedal. It is not
necessary to remove shaft from pedal support
entirely.
(7) Remove clutch pedal.
INSTALLATION
Inspect bushings in clutch and brake pedals (Fig.
24). Replace bushings if worn, cracked, or distorted.
(1) Lubricate pedal shaft, pedal shaft bore (Fig. 24)
and all bushings with Mopar Multi Mileage or high
temperature bearing grease.
(2) Position clutch pedal in support. Align pedal
with pivot shaft and slide shaft through pedal bush-
ings. Then repeat process for brake pedal.(3) Slide pedal shaft through support and install
shaft retainer.
(4) Secure push rods to clutch and brake pedals.
(5) Install brake lamp switch in bracket.
(6) Install knee bolster.
LINKAGE
REMOVAL
NOTE: The factory installed hydraulic linkage has a
quick disconnect at the slave cylinder. This fitting
should not be disconnected, the hydraulic linkage
is serviced as an assembly only, but it comes as
two pieces to ease installation. Once the clutch
hydraulic line is connected to the slave cylinder, it
should not be disconnected.
(1) Raise and support vehicle.
(2) Remove nuts attaching slave cylinder to studs
on clutch housing (Fig. 25).
(3) Remove slave cylinder from clutch housing.
(4) Remove the plastic clip securing the hydraulic
line to the dash panel from the lower dash panel
flange.
Fig. 23 Clutch Cylinder And Push Rod
1 - PIN
2 - CLUTCH INTERLOCK WIRE
3 - PUSH ROD
4 - CLIP
Fig. 24 Clutch/Brake Pedal Mounting
1 - PEDAL SUPPORT
2 - SHAFT RETAINER
3 - BRAKE PEDAL
4 - CLUTCH PEDAL
5 - SHAFT RETAINER
6 - PEDAL PIVOT SHAFT
7 - BUSHINGS
BR/BECLUTCH 6 - 15
(5) Remove the plastic clip securing the hydraulic
line to the dash panel from the upper dash panel
stud.
(6) Lower vehicle.
(7) Disconnect clutch pedal interlock switch wires.
(8) Remove retaining clip (Fig. 26).
(9) Slide clutch master cylinder push rod off pedal
pin.
(10) Inspect condition of bushing in the clutch
master cylinder pushrod (Fig. 26). Replace the clutch
hydraulic linkage if bushing is worn or damaged.
(11) Verify that cap on clutch master cylinder res-
ervoir is tight. This will avoid spillage during
removal.
(12) Remove the nuts holding the clutch master
cylinder to the dash panel.
(13) Remove screws that attach clutch fluid reser-
voir to dash panel.
(14) Remove the clutch master cylinder from the
dash panel.
(15) Remove clutch cylinders, reservoir and con-
necting lines from vehicle.
INSTALLATION
NOTE: The factory installed hydraulic linkage has a
quick disconnect at the slave cylinder, this fitting
should not be disconnected. The hydraulic linkage
is serviced as an assembly only, but it comes as
two pieces to ease installation. Once the clutch
hydraulic line is connected to the slave cylinder, it
should not be disconnected.
(1) Tighten cap on clutch fluid reservoir to avoid
spillage during installation.
(2) Position cylinders, connecting lines and reser-
voir in vehicle engine compartment. Locate the clutch
hydraulic line against the dash panel and behind all
engine hoses and wiring.
(3) Insert clutch master cylinder in dash panel.
Install and tighten the nuts to hold the clutch master
cylinder to the dash panel.
(4) Apply a light coating of grease to the inside
and outside diameter of the master cylinder bushing.
(5) Install clutch master cylinder push rod on
clutch pedal pin. Secure rod with retaining clip.
(6) Connect clutch pedal position (interlock) switch
wires.
Fig. 25 Hydraulic Clutch Linkage
1 - DASH PANEL
2 - CYLINDER RESERVOIR
3 - CLUTCH MASTER CYLINDER
4 - SLAVE CYLINDER
5 - CLUTCH HYDRAULIC LINE
Fig. 26 Clutch Cylinder Push Rod Attachment
1 - PIN
2 - CLUTCH INTERLOCK WIRE
3 - PUSH ROD
4 - CLIP
6 - 16 CLUTCHBR/BE
LINKAGE (Continued)