Rear Axle - GMC 1982 Light Duty Truck Service Manual

procedure of components in this portion of the manual as indicated at
appropriate locations by the terminology "See Notice on Page 1 of this
Section".
affect the performance of vital components and systems, an d/or could result
in major repair expense. It must be replaced with one of the same part
number or with an equivalent part if replacement becomes necessary. Do not
use a replacement part of lesser quality or substitute design. Torque values
must be used as specified during reassembly to assure proper retention of this
part.
General Description............................................................ 4B- 1
Rear Axle O p e ra tio n ....................................................... 4B- 2
Diagnosis................................................................................ 4 B - 7
Noise D iagnosis................................................................. 4B- 7
Bearing Diagnosis............................................................. 4B-11
M aintenance and Lubrication.......................................... 4B- 9
Axle Identification............................................................... 4B-13
Operational Checks and A d ju s tm e n ts ........................... 4B- 9
G ear Tooth Contact Pattern C h e c k ............................. 4B- 9
Pinion Bearing Preload.................................................... 4B- 9
The light duty truck line-up uses seven different axles,
categorized by ring gear diameter, they are as follows:
8-1 /2 " , AND 8-7/8" AND 9-1 /2" RING GEAR
AXLE
These axles, shown in figure 4B-1 and 4B-2 are the
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
a tta c h m e n t points for suspension componenets such as
shock absorbers and leaf springs. A welded flange is
provided for brake flange plate attachment.
The 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
hypoid ring gear is bolted to a one-piece differential case
which is supported by two preloaded tapered roller bearings.
On the 9 1/2" (Fig. 4B-2) ring gear side bearing
preload is controlled by a side bearing adjusting nut
threaded into the carrier near the axle tubes. Backlash is
adjusted by increasing or decreasing shim thickness.
SECTION 4B

REAR AXLE

The following notice applies to one or more steps in the assembly
N O T IC E : This fastener is an important attaching part in that it could
CONTENTS
GENERAL DESCRIPTION
Side Bearing P relo ad ....................................................... 4B-9
Pinion Depth and Backlash............................................ 4B-9
8 -1 /2 ", 8 -7 /8 ", and 9 -1 /2 " Ring G e a r ...................... 4B1-1
Chevrolet 10-1/2" Ring G e a r ....................................... 4B2-1
Dana 10-1/2" Ring G e a r ............................................... 4B3-1
Dana 9 - 3 / 4 " Ring G e a r ................................................... 4B4-1
Rockwell 12" Ring G e a r ................................................ 4B5-1
Limited Slip Differential U n i t s ..................................... 4B6-1
Specifications............................. ....... .............................. 4B10-1
Special Tools.................................................................... 4B10-1
CHEVROLET 10-1 /2" RING GEAR AXLE
The axle shown in figure 4B-3 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 10-1 /2" RING GEAR AXLE
The Dana axle shown in figure 4B-4 is a Salisbury-type
similar in design to the 8-7/8" ring gear axle. 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.
REAR AXLE 4B-1