1994 JEEP CHEROKEE differential

0.015 in. (0.38 mm) thick shim on this hub. This will
provide the required differential bearing preload
torque.
(10) Install bearings on hubs with Installer
C-3716-A and Handle C-4171 (Fig. 59).
(11) Match each bearing cup with bearing (origi-
nal). Install the cups on the bearings.
DIFFERENTIAL INSTALLATION
(1) Position Spreader W-129-B with the tool dowel
pins seated in the locating holes (Fig. 60). Install the
holddown clamps and tighten the tool turnbuckle fin-
ger-tight.
(2) Install a pilot stud at the left side of the differ-
ential housing. Attach Dial Indicator to housing pilotstud. Load the indicator plunger against the opposite
side of the housing (Fig. 60) and zero the indicator.
CAUTION: Do not spread over 0.38 mm (0.015 in). If
the housing is over-separated, it could be distorted
or damaged.
(3) Spread the housing enough to install the case
in the housing. Measure the distance with the dial
indicator (Fig. 60).
(4) Remove the dial indicator.
(5) Install case in the housing. Tap the differential
case to ensure the bearings are fully seated (Fig. 61).
Remove the spreader.
(6) Install the bearing caps at their original loca-
tions (Fig. 62). Tighten the bearing cap bolts to 61
Nzm (45 ft. lbs.) torque.
Fig. 59 Differential Bearing Installation
Fig. 60 Spread Differential Housing
Fig. 61 Differential Installation
Fig. 62 Differential Bearing Cap Reference Letters
JFRONT SUSPENSION AND AXLE 2 - 43

BACKLASH AND CONTACT PATTERN ANALYSIS
(1) Rotate assembly several revolutions to seat
bearings. Measure backlash at three equally spaced
locations around the perimeter of the ring gear with
a dial indicator (Fig. 63).
The ring gear backlash must be within 0.005 -
0.008 inch (0.12 - 0.20 mm). It cannot vary more
than 0.002 inch (0.05 mm) between the points
checked.
If backlash must be adjusted, transfer shims from
one side of carrier to the other side. Adjust the back-
lash accordingly (Fig. 64).DO NOT INCREASE
THE TOTAL SHIM PACK THICKNESS, EXCES-
SIVE BEARING PRELOAD AND DAMAGE
WILL OCCUR.If the mesh and backlash steps have been followed
in the procedures above, good gear teeth contact pat-
terns should exist.
The ring gear teeth contact patterns will show if
the pinion gear depth is correct. It will also show if
the ring gear backlash has been adjusted correctly.
The backlash must be maintained within the speci-
fied limits until the correct tooth contact patterns are
obtained.
(2) Apply a thin coat of hydrated ferric oxide (yel-
low oxide of iron) to the drive and coast side of the
ring gear teeth.
(3) Rotate the ring gear one complete revolution in
both directions while a load is being applied. Insert a
pry bar between the differential housing and the case
flange. This action will produce distinct contact pat-
terns on both the drive side and coast side of the ring
gear teeth.
(4) Note patterns in compound. Refer to (Fig. 65)
for interpretation of contact patterns and adjust ac-
cordingly.
FINAL ASSEMBLY
(1) Install the axle shafts. Refer to Axle Shaft In-
stallation in this Group.
(2) Scrape the residual sealant from the housing
and cover mating surfaces. Clean the mating sur-
faces with mineral spirits. Apply a bead of MOPARt
Silicone Rubber Sealant on the housing cover (Fig.
66). Allow the sealant to cure for a few minutes.
Install the housing cover within 5 minutes af-
ter applying the sealant. If not installed the seal-
ant must be removed and another bead applied.
(3) Install the cover on the differential with the at-
taching bolts. Install the identification tag. Tighten
the cover bolts with 41 Nzm (30 ft. lbs.) torque.
CAUTION: Overfilling the differential can result in
the lubricant foaming and overheating.
(4) Refill the differential housing with the speci-
fied quantity of MOPARtHypoid Gear Lubricant.
(5) Install the fill hole plug and tighten to 34 Nzm
(25 ft. lbs.) torque.Fig. 63 Ring Gear Backlash Measurement
Fig. 64 Backlash Shim Adjustment
2 - 44 FRONT SUSPENSION AND AXLEJ

BRAKES
CONTENTS
page page
ABS BRAKE DIAGNOSIS.................. 3
ABS COMPONENT SERVICE.............. 47
ABS SYSTEM OPERATION............... 39
ANTILOCK BRAKE SYSTEM OPERATION.... 43
BRAKE BLEEDINGÐBRAKE FLUID AND
LEVELÐBRAKELINES AND HOSES....... 13
BRAKE PEDAL AND BRAKELIGHT SWITCH . . 65
DISC BRAKES.......................... 24DRUM BRAKES........................ 34
GENERAL INFORMATION.................. 1
PARKING BRAKES...................... 56
POWER BRAKE BOOSTER................ 22
SERVICE BRAKE DIAGNOSIS.............. 7
SPECIFICATIONS....................... 67
STANDARD MASTER CYLINDER........... 20
GENERAL INFORMATION
INDEX
page page
Antilock Brake System (ABS)................ 1
Brake Fluid/Lubricants/Cleaning Solvents........ 1
Brake Safety Precautions................... 2
Brake Warning Lights...................... 1
Brakelining Material........................ 1Hydraulic Components..................... 1
Jeep Body Code Letters.................... 2
Power Brakes............................ 1
Wheel Brake Components................... 1
WHEEL BRAKE COMPONENTS
Front disc and rear drum brakes are used on all
models. The disc brake components consist of single
piston calipers and ventilated rotors. The rear drum
brakes are dual shoe, units with cast brake drums.
The parking brake mechanism is lever and cable
operated. The cables are attached to actuating levers
mounted on the rear drum brake secondary shoes.
The parking brake mechanism is operated by a foot
pedal on YJ models and a hand lever on XJ models.
POWER BRAKES
Power brakes are standard on all models. A vac-
uum operated power booster is used for standard and
ABS brake applications.
HYDRAULIC COMPONENTS
A dual reservoir master cylinder is used for all
standard brake applications. A combination propor-
tioning valve/pressure differential switch is used. A
center feed style master cylinder is used for ABS
brake applications.
BRAKELINING MATERIAL
The factory installed brakelining on all models con-
sists of an organic base material combined with me-
tallic particles. The lining does not contain asbestos.
BRAKE WARNING LIGHTS
A red, brake warning light is used to alert the
driver if a pressure differential exists between the
front and rear hydraulic systems. The light also
alerts the driver when the parking brakes are ap-
plied. The light illuminates for a few seconds at start
up as part of a bulb check procedure.
An additional warning light is used on models with
antilock brakes. This light is amber in color and is
located in the same side of the instrument cluster as
the red warning light. The amber light illuminates
only when an ABS system fault occurs.
ANTILOCK BRAKE SYSTEM (ABS)
An antilock brake system (ABS) is available on
XJ/YJ models. The system is an electronically oper-
ated, all-wheel brake control system. The ABS sys-
tem is designed to retard wheel lockup during
periods of high wheel slip braking. Refer to the anti-
lock brake section for operation and service informa-
tion.
BRAKE FLUID/LUBRICANTS/CLEANING SOLVENTS
Recommended fluid for all Jeep vehicles is Mopar
DOT 3 brake fluid, or an equivalent meeting SAE
J1703 and DOT 3 standards.
JBRAKES 5 - 1

(2) If red warning light is illuminated, or if neither
warning light is illuminated, make several stops and
note pedal action and brake response.
(3) Check brake pedal response with transmission
in Neutral and engine running. Pedal should remain
firm under steady foot pressure. If pedal falls away,
problem is either in vacuum booster or master cylin-
der.
(4) During road test, make normal and firm brake
stops in 25-40 mph range. Note faulty brake opera-
tion such as pull, grab, drag, noise, fade, pedal pul-
sation, etc.
(5) Inspect suspect brake components and refer to
problem diagnosis information for causes of various
brake conditions.
COMPONENT INSPECTION
Fluid leak points and dragging brake units can
usually be located without removing any compo-
nents. The area around a leak point will be wet with
fluid. The components at a dragging brake unit
(wheel, tire, rotor) will be quite warm or hot to the
touch.
Other brake problem conditions will require compo-
nent removal for proper inspection. Raise the vehicle
and remove the necessary wheels for better visual ac-
cess.
During component inspection, pay particular atten-
tion to heavily rusted/corroded brake components
(e.g. rotors, caliper pistons, brake return/holddown
springs, support plates, etc.).
Heavy accumulations of rust may be covering se-
vere damage to a brake component. It is wise to re-
move surface rust in order to accurately determine
the depth of rust penetration and damage. Light sur-
face rust is fairly normal and not a major concern (as
long as it is removed). However, heavy rust buildup,
especially on high mileage vehicles may cover struc-
tural damage to such important components as
brakelines, rotors, support plates, and brake boosters.
Refer to the wheel brake service procedures in this
group for more information.
DIAGNOSING SERVICE BRAKE PROBLEMS
BRAKE WARNING LIGHT OPERATION
The red brake warning light will illuminate under
the following conditions:
²for 2-3 seconds at startup as part of normal bulb
check
²parking brakes applied
²low pedal caused by malfunction in front/rear
brake hydraulic circuit (differential switch valve ac-
tuated)
If the red light remains on after startup, first ver-
ify that the parking brakes are fully released. Then
check pedal action and fluid level. A red light indi-
cates that the valve in the differential pressureswitch has been actuated. If a problem is confirmed,
inspect the hydraulic system and wheel brake compo-
nents.
On models with ABS brakes, the amber warning
light only illuminates when an ABS component has
malfunctioned. The ABS light operates indepen-
dently of the red warning light. Refer to the antilock
brake section for more detailed diagnosis informa-
tion.
PEDAL FALLS AWAY
A brake pedal that falls away under steady foot
pressure is generally the result of a system leak. The
leak point could be at a brakeline, fitting, hose,
wheel cylinder, or caliper. Internal leakage in the
master cylinder caused by worn or damaged piston
cups, may also be the problem cause.
If leakage is severe, fluid will be evident at or
around the leaking component. However internal
leakage in the master cylinder will not be physically
evident. Refer to the cylinder test procedure in this
section.
LOW PEDAL
If a low pedal is experienced, pump the pedal sev-
eral times. If the pedal comes back up, worn lining
and worn rotors or drums are the most likely causes.
However, if the pedal remains low and/or the warn-
ing light illuminates, the problem is in the master
cylinder, wheel cylinders, or calipers.
A decrease in master cylinder fluid level may only
be the result of normal lining wear. Fluid level will
decrease as lining wear occurs. It is a result of the
outward movement of caliper and wheel cylinder pis-
tons to compensate for normal wear.
SPONGY PEDAL
A spongy pedal is most often caused by air in the
system. However, thin drums or substandard brake
lines and hoses will also cause a condition similar to
a spongy pedal. The proper course of action is to
bleed the system, or replace thin drums and suspect
quality brake lines and hoses.
HARD PEDAL OR HIGH PEDAL EFFORT
A hard pedal or high pedal effort may be due to
lining that is water soaked, contaminated, glazed, or
badly worn. The power booster or check valve could
also be faulty. Test the booster and valve as de-
scribed in this section.
BRAKE DRAG
Brake drag occurs when the lining is in constant
contact with the rotor or drum. Drag can occur at
one wheel, all wheels, fronts only, or rears only. It is
a product of incomplete brakeshoe release. Drag can
be minor or severe enough to overheat the linings,
rotors and drums.
5 - 8 BRAKESJ

POWER BRAKE BOOSTER
INDEX
page page
Power Brake Booster Installation............. 23
Power Brake Booster Operation............. 22Power Brake Booster Removal.............. 22
Service Information....................... 22
SERVICE INFORMATION
The power brake booster is not a serviceable com-
ponent. If a booster malfunction occurs, the booster
must be replaced as an assembly. The booster (Figs.
1 and 2), is attached to the dash panel and pedal sup-
port.
POWER BRAKE BOOSTER OPERATION
Booster Components
The booster assembly consists of a housing divided
into separate chambers by an internal diaphragm.The outer edge of the diaphragm is attached to the
booster housing. The diaphragm is in turn, connected
to the booster push rod.
Two push rods are used to operate the booster. One
push rod connects the booster to the brake pedal. The
second push rod (at the forward end of the housing),
strokes the master cylinder pistons. The rear push
rod is connected to the two diaphragms in the booster
housing.
The atmospheric inlet valve is opened and closed
by the push rod connected to the brake pedal. The
booster vacuum supply is through a hose attached to
a fitting on the intake manifold. The hose is con-
nected to a vacuum check valve in the booster hous-
ing. The check valve is a one-way device that
prevents vacuum leak back.
How Brake Boost Is Generated
Power assist is generated by utilizing the pressure
differential between normal atmospheric pressure
and a vacuum. The vacuum needed for booster oper-
ation is taken directly from the engine intake mani-
fold. The entry point for atmospheric pressure is
through an inlet valve at the rear of the housing.
The forward portion of the booster housing (area in
front of the two diaphragms), is exposed to manifold
vacuum. The rear portion (area behind the dia-
phragms), is exposed to normal atmospheric pressure
of 101.3 kilopascals (14.7 pounds/square in.).
Pressing the brake pedal causes the rear push rod
to open the inlet valve. This exposes the area behind
the diaphragm to atmospheric pressure. The result-
ing force applied to the diaphragm is what provides
the extra apply pressure for power assist.
POWER BRAKE BOOSTER REMOVAL
(1) Loosen but do not remove nuts attaching mas-
ter cylinder to booster (Fig. 3).
(2) Remove instrument panel lower trim cover.
(3) Remove retaining clip attaching booster push
rod to brake pedal (Fig. 4).
(4) Remove bolts/nuts attaching booster to dash
panel.
(5) In engine compartment, loosen vacuum hose
clamp and disconnect vacuum hose from booster
check valve (Fig. 5).
(6) Remove master cylinder attaching nuts and re-
move cylinder from mounting studs on booster.
Fig. 1 Power Brake Booster (XJ)
Fig. 2 Power Brake Booster (YJ)
5 - 22 BRAKESJ

(5) Fill and bleed brake system.
COMBINATION VALVE REPLACEMENTÐXJ
The combination valve is not a repairable compo-
nent. The valve is serviced as an assembly whenever
diagnosis indicates replacement is necessary.
(1) Remove air cleaner housing for access to valve,
if necessary.
(2) Remove bolt attached valve to master cylinder
(Fig. 20).
(3) Disconnect pedal travel sensor harness connec-
tor and move harness wires aside for working access
if necessary.
(4) Disconnect pressure differential switch wires at
valve.
(5) Disconnect hydraulic lines at valve and remove
valve from vehicle.
(6) Connect hydraulic lines to valve.
(7) Position valve bracket on master cylinder and
install bracket attaching bolt.(8) Reconnect pressure differential switch and
pedal travel sensor wires.
(9) Bleed brake system. Refer to procedure in this
section.
COMBINATION VALVE REPLACEMENTÐYJ
The combination valve mounting bracket is perma-
nently attached to the valve. The bracket and valve
are serviced as an assembly.
(1) Disconnect harness wires from combination
valve switch.
(2) Disconnect brakelines attached to combination
valve.
(3) Remove nuts attaching combination valve
bracket to master cylinder mounting studs (Fig. 19).
(4) Remove valve and bracket as assembly.
(5) Start all brakelines in combination valve by
hand. Tighten line fittings just enough to prevent
leaks.
(6) Position valve mounting bracket on studs.
(7) Install and tighten nuts that attach combina-
tion valve bracket to studs on power brake booster.
(8) Connect wires to combination valve switch.
(9) Fill and bleed brake system.
(10) Final-tighten brakeline fittings to 18-23 Nzm
(160-210 in. lbs.) torque after bleeding brakes.
Fig. 19 HCU Mounting (YJ)
Fig. 20 Combination Valve Mounting (XJ)
JABS COMPONENT SERVICE 5 - 55

30RH/32RH TRANSMISSION DIAGNOSIS
INDEX
page page
Air Pressure Test........................ 73
Analyzing the Road Test................... 70
Converter Housing Leak Diagnosis........... 73
Converter Stall Test...................... 72
Diagnosis Guides and Charts............... 76
Fluid Level and Condition.................. 69Gearshift Linkage........................ 70
General Information....................... 69
Hydraulic Pressure Test................... 71
Preliminary Diagnosis..................... 69
Road Test.............................. 70
Transmission Throttle Valve Cable Adjustment . . 70
GENERAL INFORMATION
Automatic transmission problems are generally the
result of:
²poor engine performance
²incorrect fluid level
²incorrect cable/linkage adjustment
²incorrect band adjustment
²incorrect hydraulic control pressure adjustments
²hydraulic component malfunctions
²mechanical component malfunctions.
Begin diagnosis by checking the easily accessible
items such as fluid level, fluid condition and control
linkage adjustment. A road test will determine if fur-
ther diagnosis is necessary.
Procedures outlined in this section should be per-
formed in the following sequence to realize the most
accurate results:
²Preliminary diagnosis
²Check fluid Level and condition
²Check control linkage Adjustment
²Road test
²Stall test
²Hydraulic pressure test
²Air pressure tests
²Leak Tests
²Analyze test results and consult diagnosis charts
PRELIMINARY DIAGNOSIS
Two basic procedures are required. One procedure
for vehicles that are driveable and an alternate pro-
cedure for disabled vehicles (will not back up or
move forward).
Vehicle Is Driveable
(1) Check fluid level and condition.
(2) Adjust throttle cable and gearshift linkage if
complaint was based on delayed, erratic, or harsh
shifts.
(3) Road test vehicle and note transmission operat-
ing characteristics.
(4) Perform stall test if complaint is based on slug-
gish, low speed acceleration or abnormal throttle
opening needed to maintain normal speeds with
properly tuned engine.
(5) Perform hydraulic pressure tests.(6) Perform air pressure test to check clutch-band
operation.
Vehicle Is Disabled
(1) Check fluid level and condition.
(2) Check for broken, disconnected throttle link-
age.
(3) Check for cracked, leaking cooler lines, or
loose, missing pressure port plugs.
(4) Raise vehicle, start engine, shift transmission
into gear and note following:
(a) If propeller shafts turn but wheels do not,
problem is with differential or axle shafts.
(b) If propeller shafts do not turn and transmis-
sion is noisy, stop engine. Remove oil pan, and
check for debris. If pan is clear, remove transmis-
sion and check for damaged drive plate, converter,
oil pump or input shaft.
(c) If propeller shafts do not turn and transmis-
sion is not noisy, perform hydraulic pressure test to
determine if problem is a hydraulic or mechanical.
FLUID LEVEL AND CONDITION
(1) Position vehicle on level surface. This is impor-
tant in obtaining an accurate fluid level check.
(2) To avoid false readings, which could produce
under or over fill condition, do not check level until
fluid is at normal operating temperature.
(3) Shift transmission into Neutral.
(4) Apply parking brakes.
(5) Operate engine at curb idle speed.
WARNING: WHEN PERFORMING UNDERHOOD OP-
ERATIONS WITH THE ENGINE RUNNING, KEEP
YOUR HANDS WELL AWAY FROM HOT OR ROTAT-
ING ENGINE COMPONENTS. DO NOT WEAR
LOOSE ARTICLES OF CLOTHING WHICH COULD
BECOME ENTANGLED IN ENGINE COMPONENTS
OR ACCESSORIES.
(6) Clean dipstick filler cap and tube before remov-
ing dipstick.
(7) Remove dipstick and inspect fluid level.
²Correct level is to FULL mark
²Acceptable level is between ADD and FULL marks
J30RH/32RH TRANSMISSION DIAGNOSIS 21 - 69

NP242 TRANSFER CASE
INDEX
page page
Cleaning and Inspection.................. 305
General Information...................... 293
Shift Linkage Adjustment.................. 296
Speedometer Service.................... 296
Transfer Case Assembly.................. 306
Transfer Case Disassembly and Overhaul..... 297Transfer Case Fill Level.................. 294
Transfer Case Identification................ 293
Transfer Case Installation................. 296
Transfer Case Lubricant.................. 294
Transfer Case Removal................... 296
GENERAL INFORMATION
The NP242 is a both a full and part time transfer
case with four operating ranges (Fig. 1). The NP242
provides either 2-wheel drive or full time 4-wheel
drive operation. An interaxle differential is used to
control torque transfer to the front and rear axles. A
low range gear reduction system provides increased
low speed torque capability.
OPERATING RANGES
The NP242 transfer case operating ranges are: 2-
wheel drive, part-time 4-wheel drive, full time 4-
wheel drive and 4-wheel drive low.
The2Hand4x4full time ranges are for all road
surfaces. The 2H range provides 2-wheel drive. The 4
x 4 full time range provides differentiated, 4-wheel
drive. The vehicle can be operated on any road sur-
face in either of these ranges if desired.
The transfer case differential also has a locking
mechanism for undifferentiated operation in:4x4
part time and,4x4lowranges. These ranges are
only for use on low traction surfaces.
The4x4full time range is fully differentiated and
can be used at any time and on any road surface. The 4x 4 part time and low ranges are not differentiated.
They are for off road use only.
The low range reduction gear system is operative in
4-low range only. Low range reduction ratio is 2.72:1.
In summary, 2H and4x4full time ranges are for
normal on-road, highway operation. The4x4part-
time and low ranges are for off road operation exclu-
sively. Or, or when the vehicle is driven on surfaces
covered by snow, ice or similar low traction elements.
SHIFT MECHANISM
Transfer case operating ranges are selected with a
floor mounted shift lever. The shift lever is connected
to the transfer case range lever by an adjustable
linkage rod. Range positions are marked on the
shifter bezel plate (Fig. 2).
TRANSFER CASE IDENTIFICATION
A circular I.D. tag is attached to the rear case of
each NP242 transfer case (Fig. 3). The tag provides
the transfer case model number, assembly number,
serial number and low range ratio.
Fig. 1 NP242 Transfer Case
Fig. 2 NP242 Shift Pattern
JNP242 TRANSFER CASE 21 - 293