8 1/4 Rear Axle; 8 1/4 Axle Description And Operation - Jeep Cherokee 2000 Service Manual

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DESCRIPTION AND OPERATION
8 1/4 AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
LUBRICANT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
STANDARD DIFFERENTIAL . . . . . . . . . . . . . . . . 105
TRAC-LOK DIFFERENTIAL . . . . . . . . . . . . . . . 105
DIAGNOSIS AND TESTING
GENERAL INFORMATION . . . . . . . . . . . . . . . . . 106
GEAR NOISE . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
BEARING NOISE . . . . . . . . . . . . . . . . . . . . . . . . 109
LOW SPEED KNOCK . . . . . . . . . . . . . . . . . . . . . 109
VIBRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
DRIVELINE SNAP . . . . . . . . . . . . . . . . . . . . . . . 109
TRAC–LOK DIFFERENTIAL NOISE . . . . . . . . . 109
TRAC–LOK TEST . . . . . . . . . . . . . . . . . . . . . . 110
SERVICE PROCEDURES
LUBRICANT CHANGE . . . . . . . . . . . . . . . . . . . . 110
REMOVAL AND INSTALLATION
REAR AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
AXLE SHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
AXLE SEAL AND BEARING . . . . . . . . . . . . . . . . 112
PINION SEAL . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
DESCRIPTION AND OPERATION
8 1/4 AXLE
DESCRIPTION
The 8 1/4 inch axle housings consist of a cast iron
center section with axle tubes extending from either
side. The tubes are pressed into and welded to the
differential housing to form a one-piece axle housing
(Fig. 1).
The axles have a vent hose to relieve internal pres-
sure caused by lubricant vaporization and internal
expansion.
The axles are equipped with semi-floating axle
shafts, meaning vehicle loads are supported by the
axle shaft and bearings. The axle shafts are retained
by C-locks in the differential side gears.
The removable, stamped steel cover provides a
means for inspection and service without removing
the complete axle from the vehicle.
The 8 1/4 axle have a date tag and a gear ratio tag.
The tags are attached to the differential housing by a
cover bolt.
The differential case is a one-piece design. The dif-
ferential pinion mate shaft is retained with a

8 1/4 REAR AXLE

TABLE OF CONTENTS
page
DIFFERENTIAL. . . . . . . . . . . . . . . . . . . . . . . . . . 114
DIFFERENTIAL SIDE BEARINGS . . . . . . . . . . . . 115
RING GEAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
PINION GEAR . . . . . . . . . . . . . . . . . . . . . . . . . . 117
DISASSEMBLY AND ASSEMBLY
STANDARD DIFFERENTIAL . . . . . . . . . . . . . . . . 120
TRAC-LOK
CLEANING AND INSPECTION
8 1/4 AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
TRAC-LOK
ADJUSTMENTS
8 1/4 AXLE PINION GEAR DEPTH . . . . . . . . . . . 126
DIFFERENTIAL BEARING PRELOAD AND
GEAR BACKLASH. . . . . . . . . . . . . . . . . . . . . . 127
GEAR CONTACT PATTERN ANALYSIS. . . . . . . . 129
SIDE GEAR CLEARANCE . . . . . . . . . . . . . . . . . 129
SPECIFICATIONS
8 1/4 INCH AXLE . . . . . . . . . . . . . . . . . . . . . . . . 131
8 1/4 INCH AXLE . . . . . . . . . . . . . . . . . . . . . . . . 131
SPECIAL TOOLS
8 1/4 AXLES. . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
threaded pin. Differential bearing preload and ring
gear backlash are set and maintained by threaded
adjusters at the outside of the differential housing.
Pinion bearing preload is set and maintained by the
use of a collapsible spacer.
Axles equipped with a Trac-Lok
optional. A Trac-Lok differential has a one-piece dif-
ferential case, and the same internal components as
a standard differential, plus two clutch disc packs.
AXLE IDENTIFICATION
The axle differential cover can be used for identifi-
cation of the axle (Fig. 2). A tag is also attached to
the cover.
OPERATION
The axle receives power from the transmission/
transfer case through the rear propeller shaft. The
rear propeller shaft is connected to the pinion gear
which rotates the differential through the gear mesh
with the ring gear bolted to the differential case. The
engine power is transmitted to the axle shafts
through the pinion mate and side gears. The side
gears are splined to the axle shafts.
8 1/4 REAR AXLE
DIFFERENTIAL . . . . . . . . . . . . . . . 121
. . . . . . . . . . . . . . . . . . . . . . . . . . . 125
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differential are