Lubricant Specifications; Trac-Lok Operation - Jeep Wrangler 1997 Manual

TJ
GENERAL INFORMATION (Continued)
LUBRICANT SPECIFICATIONS
Multi-purpose, hypoid gear lubricant should be
used . The lubricant should have MIL-L-2105C and
API GL 5 quality specifications . ~Mopar Hypoid Gear
Lubricant conforms to both of these specifications .
" Lubricant is a thermally stable SAE 80W-90
gear lubricant .
" Lubricant for axle with Trailer Tow is SAE
75W-140 SYNTHETIC gear lubricant .
" Trac-Lok differentials add 4 oz. of friction mod-
ifier.
" Lubricant capacity is 1 .66
L
(3 .50 pts .).
CAUTION: If axle is submerged in water, lubricant
must be replaced immediately ° to avoid possible
premature axle failure.
DESCRIPTION AND OPERATION
AXLES
TJ vehicles are equipped with
a
194 FBI rear axle.
The 194 FBI axle housing has a cast iron center
section . Two steel axle shaft tubes are pressed and
welded into the center section .
It is not necessary to remove the axle from the
vehicle for service . A removable differential cover is
provided for routine vehicle service . If the differential
housing is damaged, the complete axle assembly can
be removed .
IDENTIFICATION
194 FBI axle has the assembly part number and
gear ratio listed on a tag. The tag is attached to the
left side of the housing cover. B ild date identifica-
tion codes on axles are stamped on the axle shaft
tube cover side . The 194 FBI axle has a flat housing
cover gasket flange at the outer edge.
STANDARD DIFFERENTIAL OiPERATION
The differential gear system 'idivides the torque
between the axle shafts . It allows the axle shafts to
rotate at different speeds when turning corners .
Each differential side gear is ~splined to an axle
shaft. The pinion gears are mounted on a pinion
mate shaft and are free to rotate on the shaft. The
pinion gear is fitted in a bore in the differential case
and is positioned at a right angle, to the axle shafts .
In operation, power flow occurs' as follows :
" The pinion gear rotates the #ng gear
" The ring gear (bolted to the differential case)
rotates the case
" The differential pinion gear (mounted on the
pinion mate shaft in the case) rotate the side gears
" The side gears (splined to the axle shafts) rotate
the shafts
DIFFERENTIAL AND DRIVELINE
3-47
During straight ahead driving, the differential pin-
ion gears do not rotate on the pinion mate shaft. This
occurs because input torque applied to the gears is
divided and distributed equally between the two side
gears. As a result, the pinion gears revolve with the
pinion mate shaft but do not rotate around it (Fig. 2).
IN STRAIGHT AHEAD DRIVING
EACH WHEEL ROTATES AT 100%
OF CASE SPEED
PINION GEARS ROTATE
WITH CASE
J9303-13
Fig. 2 Differential Operation-Straight Ahead Driving
When turning corners, the outside wheel must
travel a greater distance than the inside wheel in
order to complete a turn . The difference must be
compensated for, to prevent the tires from scuffing
and skidding through turns. To accomplish this, the
differential allows the axle shafts to turn at unequal
speeds (Fig. 3). In this instance, the input torque
applied to the pinion gears is not divided equally. .
The pinion gears now rotate around the pinion mate
shaft in opposite directions. This allows the side gear
and axle shaft attached to the outside wheel to rotate
at a faster speed.
OUTER WHEEL 100% DIFFERENTIAL
INNER WHEEL
110% CASE SPEED CASE SPEED 90% CASE SPEED
PINION GEARS ROTATE
ON PINION SHAFT
Fig. 3 Differential Operation-On Turns
.19303-14
TRAC-LOK OPERATION
In a conventional differential, the torque applied to
the ring gear is transmitted to the axle shafts