FLANGE
ROLLER BEARING
YOKE
OIL
SNAPRING
SEAL
NUTS
UNIVERSAL
ROLLER BEARING
JOINT
ASSEMBLY
PROPELLER
SHAFT
SLIP JOINT
ROLLER
SNAPRING
SPLINE
JOURNAL
BEARING
CORK
GASKET
U-BOLT
SNAPRING
LOCK PLATE
OIL
SEAL
DUST
CAP
FIXED YOKE
ASSEMBLED IN
JOURNAL
SPLINED SLIDING YOKE
SAME PLANE
FLANGE YOKE
ASf02081
Figure 2-81.--Propeller shaft assembly.
spider fit into bearings in the end of the driving shaft
transmission is some distance from the differential.
yoke, and the other two arms (trunnions) are assembled
Solid shafts are usually used on tow tractors because
in the end of the driven shaft yoke. When the two shafts
the shaft is very short.
are at an angle to each other, the bearings in the yokes
The slip joint is necessary because the movement
permit the yokes to swing on the trunnions with each
between the transmission and the differential requires
revolution. (Universal joints may have roller bearings
that the propeller shaft be able to shorten or lengthen
around the trunnions.)
itself. On vehicles having rear springs, the differential
Slip joints and universal joints require little
moves up and down as the rear wheels move over
maintenance, except for those that need lubrication
uneven surfaces. This up and down movement
where fitted with grease fittings. Others may be factory
lengthens and shortens the distance between the
packed with grease and not need lubrication. Repair is
transmission and the differential. On vehicles such as
normally limited to removal and replacement of worn
tow tractors that have no rear springs, the slip joint is
bearings, which are pressed out and replaced with new
necessary because the distance between the
ones, as illustrated in figure 2-82.
transmission and the differential still increases and
decreases when the vehicle moves over uneven
surfaces. Vibration of the engine on its shock mounts
RECEIVER
SOCKET
and expansion and contraction also necessitate a slip
joint.
Because the differential is situated below the level
of the transmission, universal joints are necessary to
DRIVER SOCKET
permit the change of direction of drive. The usual type
of slip joint consists of a splinted shaft that fits into a
splinted sleeve, as shown in figure 2-81. The splints
permit the continuing transmission of power as the
sleeve moves back and forth on the shaft. A universal
joint is essentially a double-hinged joint consisting of a
Y-shaped yoke on the driven shaft, another Y-shaped
yoke on the driving shaft, and a cross-shaped member
ASf02082
called the spider. Figure 2-81 shows a common
Figure 2-82.--Universal joint removal.
universal joint. Two of the four arms (trunnions) of the
2-71
