Chevrolet 1980 Light Duty Truck Service Manual page 328

4B-2 REAR AXLE
EQUAL TRACTION IN
STRAIGHT AHEAD DRIVING
BALANCED FORCES MAKE
DIFFERENTIAL SEEM LOCKED
Fig. 4B-1~Differential Inactive
Six distinct axles compromise the truck line-up. These
six, categorized by ring gear diameter, are a) 8-1/2" and b)
8-7/8" Ring Gear, c) Chevrolet 10-1/2" Ring Gear, d)
Dana 10-1/2" Ring Gear, e) Dana 9-3/4" Ring Gear and
f)Chevrolet 12-1/4" Ring Gear.
8 -1 /2 " and 8 -7 /8 " Ring Gear Axle
The axle shown in figure 4B-4 is a semifloating,
fabricated constructed type consisting of a cast carrier with
large bosses on each end into which two welded steel tubes
are fitted. The carrier contains an overhung hypoid pinion
and ring gear. The differential is a two pinion arrangement.
The axle housing is made up of two steel welded tubes
pressed into the crossbore of the cast carrier. Each tube is
puddle welded to the carrier. Welded-on brackets provide
attachment points for suspension componenets such as
shock absorbers and leaf springs. A welded flange is
provided for brake flange plate attachment.
An overhung hypoid drive pinion is supported by two
preloaded tapered roller bearings. The pinion shaft is sealed
by means of a molded, spring loaded, rubber seal. The seal
is mounted on the pinion flange which is splined and bolted
OUTSIDE WHfEL
M AS FARTHER/^
TO TRAVEL f
BOTH
TURN AT SAME
SPEED WHEN
Fig. 4B -2~ N e e d for D ifferen tial Action
w h e e l s
TRAVELING
STRAI6HT
to the hypoid pinion shaft.
The hypoid ring gear is bolted to a one-piece
differential case which is supported by two preloaded
tapered roller bearings.
Chevrolet 1 0-1/2 " Ring Gear Axle
The axle shown in figure 4B-5 is of the full floating type
with hypoid ring gear and drive pinion. The full floating
construction enables easy removal of axle shafts without
removing truck load and without jacking up the axle. The
differential carrier is heavily ribbed to provide rigid support
for the differential assembly.
The straddle-mounted drive pinion is supported at the
front by two opposed tapered roller bearings. The pinion
straddle bearing is a roller bearing assembly consisting of
an outer race and roller assembly. A precision ground
diameter on the pinion pilot functions as an inner race.
Side bearing preload and ring gear-to-pinion backlash
are controlled by side bearing adjusting nuts threaded into
the carrier near the axle tubes. Pinion depth is controlled
by a shim located between the pinion bearing retainer
assembly and the differential carrier.
Dana 1 0-1/2 " Ring Gear Axle
The Dana axle shown in figure 4B-6 is a Salisbury-type
similar in design to the 8-7/8" ring gear axle in figure 4B-4.
It does differ in several points, however. The axle shafts are
full floating; the carrier must be spread to remove the
differential; and the drive pinion incorporates two shim
packs. The inner pack controls pinion depth, while the outer
pack controls pinion bearing preload.
Dana 9 -3 /4 " Ring Gear Axle
The Dana axle shown in figure 4B-7 is similar to the
unit shown in 4B-6; however, the differential side bearing
shims are located between the case and the side bearings.
Chevrolet 1 2-1/4 " Ring Gear Axle
(1 1 ,0 0 0 Pound Capacity)
The 11,000 lb. capacity, single-speed hypoid axle,
illustrated in figure 4B-8, has a straddle mounted drive
pinion which is supported at the rear by a straight roller
bearing. The pinion front bearing consists of a double row
LIG H T T R U C K S ER V IC E M AN UAL