Jeep 1996 Grand Cherokee Service Manual - page 90
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. 4). 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.
TRAC-LOK OPERATION
In a conventional differential, the torque applied to
the ring gear is transmitted to the axle shafts
through the differential gears. During normal opera-
tion, the torque transmitted to each wheel is equal at
all times. However, if one wheel spins, the opposite
wheel will generate only as much torque as the spin-
ning wheel.
In the Trac-lok differential, part of the ring gear
torque is transmitted through clutch packs. The
clutch packs contain multiple disc. The clutch will
have radial grooves on the plates, and concentric
grooves on the discs or bonded fiber material that is
smooth appearance.
In operation, the Trac-lok clutches are engaged by
two concurrent forces. The first being preload force
exerted through Belleville spring washers contained
in the clutch packs. The second from separating
forces generated by the side gears as torque is
applied through the ring gear (Fig. 5).
The Trac-lok design provides differential action
needed for turning corners and for driving straight
ahead. However, when one wheel looses traction, the
clutch packs transfer additional torque to the wheel
having the most traction. Trac-lok differentials resist
wheel spin on bumpy roads and provide more pulling
power when one wheel looses traction. Pulling power
is provided continuously until both wheels loose trac-
tion. If both wheels slip due to unequal traction,
Trac-lok operation is normal. In extreme cases of dif-
ferences of traction, the wheel with the least traction
may spin.
Fig. 3 Differential Operation—Straight Ahead Driving
Fig. 4 Differential Operation—On Turns
Fig. 5 Trac-lok Limited Slip Differential Operation
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DIFFERENTIAL AND DRIVELINE
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DESCRIPTION AND OPERATION (Continued)