Jeep 1997 Grand Cherokee Service Manual page 73

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GENERAL INFORMATION
181 FBI AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . 15
LUBRICANT SPECIFICATIONS
DESCRIPTION AND OPERATION
STANDARD DIFFERENTIAL . . . . . . . . . . . . . . . 16
DIAGNOSIS AND TESTING
BEARING NOISE . . . . . . . . . . . . . . . . . . . . . . . 17
DRIVELINE SNAP . . . . . . . . . . . . . . . . . . . . . . 17
FRONT AXLES . . . . . . . . . . . . . . . . . . . . . . . . . 18
GEAR NOISE . . . . . . . . . . . . . . . . . . . . . . . . . . 16
GENERAL INFORMATION . . . . . . . . . . . . . . . . 16
LOW SPEED KNOCK . . . . . . . . . . . . . . . . . . . . 17
VIBRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
SERVICE PROCEDURES
LUBRICANT CHANGE . . . . . . . . . . . . . . . . . . . 20
REMOVAL AND INSTALLATION
AXLE BUSHING REPLACEMENT . . . . . . . . . . . 30
AXLE CONSTANT–VELOCITY (C/V) JOINT
BOOT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
AXLE SHAFT OIL SEAL . . . . . . . . . . . . . . . . . . 32
AXLE SHAFT—CARDAN U-JOINT . . . . . . . . . . 21
COLLAPSIBLE SPACER . . . . . . . . . . . . . . . . . . 24
DIFFERENTIAL SIDE BEARINGS . . . . . . . . . . . 31
GENERAL INFORMATION
181 FBI AXLE
The 181 Front Beam-design Iron (FBI) axle con-
sists of a cast iron differential housing with axle
shaft tubes extending from either side. The tubes are
pressed into the differential housing and welded.
The integral type housing, hypoid gear design has
the centerline of the pinion set below the centerline
of the ring gear.
The axle has a fitting for a vent hose used to
relieve internal pressure caused by lubricant vapor-
ization and internal expansion.
The axles are equipped with semi–floating axle
shafts, meaning that loads are supported by the hub
bearings. The axle shafts are retained by nuts at the
hub bearings. The hub bearings are bolted to the
steering knuckle at the outboard end of the axle tube
yoke. The hub bearings are serviced as an assembly.
For vehicles with ABS brakes, the ABS wheel
speed sensors are attached to the knuckle assem-
blies. The tone rings for the ABS system are pressed
onto the axle shaft. Do not damage ABS tone
wheel or the sensor when removing axle shafts.
181 FBI AXLE
INDEX
page
. . . . . . . . . . . . 15
DIFFERENTIAL AND DRIVELINE
DIFFERENTIAL . . . . . . . . . . . . . . . . . . . . . . . . 30
DRIVE AXLE ASSEMBLY . . . . . . . . . . . . . . . . . 20
HUB BEARING AND AXLE SHAFT . . . . . . . . . . 27
PINION GEAR . . . . . . . . . . . . . . . . . . . . . . . . . 32
PINION SHAFT SEAL . . . . . . . . . . . . . . . . . . . . 23
RING GEAR . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
STEERING KNUCKLE AND BALL STUDS
DISASSEMBLY AND ASSEMBLY
FINAL ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . 38
STANDARD DIFFERENTIAL . . . . . . . . . . . . . . . 37
CLEANING AND INSPECTION
AXLE COMPONENTS
CARDAN U-JOINT . . . . . . . . . . . . . . . . . . . . . . 38
ADJUSTMENTS
DIFFERENTIAL BEARING PRELOAD AND
GEAR BACKLASH . . . . . . . . . . . . . . . . . . . . . 41
GEAR CONTACT PATTERN ANALYSIS
PINION GEAR DEPTH . . . . . . . . . . . . . . . . . . . 39
SPECIFICATIONS
181 FBI AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . 44
181 FBI AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . 46
SPECIAL TOOLS
181 FBI AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . 46
The stamped steel cover provides a means for
inspection and servicing the differential.
The 181 FBI axle has the assembly part number
and gear ratio listed on a tag. The tag is attached to
the housing cover by a cover bolt. Build date identi-
fication codes are stamped on the cover side of the
axle shaft tube.
The differential case is a one–piece design. The dif-
ferential pinion mate shaft is retained with a roll
pin. Differential bearing preload and ring gear back-
lash is adjusted by the use of shims (select thick-
ness). The shims are located between the differential
bearing cones and case. Pinion bearing preload is set
and maintained by the use of a collapsible spacer.
LUBRICANT SPECIFICATIONS
A multi–purpose, hypoid gear lubricant which con-
forms to the following specifications should be used.
Mopar Hypoid Gear Lubricant conforms to all of
these specifications.
• The lubricant should have MIL–L–2105C and
API GL 5 quality specifications.
• Lubricant is a thermally stable SAE 80W–90
gear lubricant.
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