Chapter 12 Driveline and Wheel Components 253
Drive Shafts
All rear-wheel drive vehicles use a drive shaft to
transfer engine power from the transmission to the rear
axle. Drive shafts are large hollow tubes that are carefully
balanced to reduce vibration. Flexible joints are installed at
each end through yokes, which are the mounting points for
the joints. Figure 12-5 is an illustration of a typical rear-
wheel-drive drive shaft. Four-wheel drive vehicles have a
front drive shaft that directs power from the four-wheel
drive transfer case to the front axle, Figure 12-6.
Bearing
retainer
Bearing
retainer nut
Bearing
Axle
shaft
Rear axle housing
Brake backing plate
A
Seal
C-clip lock
Axle
shaft
Side
gear
Ring gear B
Figure 12-3. A—A bearing retainer is used to hold this axle shaft in the axle housing. B—A C-clip lock placed in a grooved slot on
the end of this axle shaft holds the shaft in the housing. (General Motors & Dodge)
Steering
knuckle
Flexible joint
Tie rod
Tie rod jam nut
Connecting rod
assembly
Steering stabilizer
Pitman arm
Figure 12-4. A four-wheel drive front axle assembly. (Chevrolet)
Some drive shafts are two-piece types, Figure 12-7.
Two-piece drive shafts are usually used on large trucks,
where a single drive shaft would be overstressed and
break, and on some luxury cars, where any vibration
would be objectionable. When a two-piece drive shaft is
used, an extra flexible joint is necessary.
Slip Yoke
When the rear wheels move up and down, the
distance between the transmission and rear axle assembly