The movement of the rear axle assembly also
causes the distance between the rear axle and
transmission to change. (T/F)
When is a center support bearing needed and
Grinding or squeaking from the drive shaft is
frequently caused by
How do you check for worn universal joints?
If a universal joint fails to press together with
normal force, it is possible that one of the needle
bearings has fallen out of place. (T/F)
Learning Objective: Identify differential design
variations. Describe the principles of the limited slip
differential. Explain basic service and repair of a
differential. Explain the adjustment of the ring and
Another important unit in the power train is the
differential, which is driven by the final drive. The
differential is located between the axles and permits
one axle to turn at a different speed from that of the
other. The variations in axle speed are necessary when
a vehicle rounds a corner or travels over uneven
ground. At the same time, the differential transmits
engine torque to the drive axles. The drive axles are on
a rotational axis that is 90 degrees different than the
rotational axis of the drive shaft.
A differential assembly uses drive shaft rotation to
transfer power to the axle shafts. The term differential
can be remembered by thinking of the words different
and axle. The differential must be capable ofproviding
torque to both axles, even when they are turning at
different speeds. The differential assembly is
constructed from the following: the differential
carrier, the differential case, the pinion gear, the ring
gear, and the spider gears (fig. 5-12).
The differential carrier provides a mounting place
for the pinion gear, the differential case, and other
differential components. There are two types of
differential carriers: the removable type and the
integral (unitized) type.
REMOVABLE TYPEa carrier that bolts to
the front of the axle housing. Stud bolts are
installed in the housing to provide proper carrier
Figure 5-12.Conventional differential.
alignment. A gasket is installed between the
carrier and the housing to prevent leakage.
I N T E G R A L T Y P E a c a r r i e r t h a t i s
constructed as part of the axle housing. A
stamped metal or cast aluminum cover bolts to
the rear of the carrier for inspection of the gears.
The differential case holds the ring gear, the spider
gears, and the inner ends of the axles. It mounts and
rotates in the carrier. Case bearings fit between the
outer ends of the differential case and the carrier.
The pinion gear turns the ring gear when the drive
shaft is rotating. The outer end of the pinion gear is
splined to the rear U-joint companion flange or yoke.
The inner end of the pinion gear meshes with the teeth
on the ring gear.
The pinion gear is mounted on tapered roller
bearings that allow the pinion gear to move freely on
the carrier. Either a crushable sleeve or shims are used
to preload the pinion gear bearings. Some differentials
use a pinion pilot bearing that supports the extreme
inner end of the pinion gear. The pinion pilot bearing
assists the tapered roller bearings in supporting the
pinion gear during periods of heavy loads.
The pinion gear drives the ring gear. It is bolted
securely to the differential case and has more teeth than
the pinion gear. The ring gear transfers rotating power
through an angle change or 90 degrees.