Pontiac FIREBIRD 1972 Service Manual page 369

SECTION 4 C
T Y P E C S T A N D A R D DIFFERENTIAL
The following caution applies to one or more steps in the assembly proce-
dure of components in this portion of the manual as indicated at appropri-
ate locations by the terminology "See Caution on page 1 of this Section".
CAUTION: THIS FASTENER IS AN IMPOR TANT A TTACHING
PART IN THAT IT COULD AFFECT THE PERFORMANCE OF
VITAL COMPONENTS AND SYSTEMS, AND/OR COULD RE-
SUL T IN MAJOR REPAIR EXPENSE. IT MUST BE REPLACED
WITH ONE OF THE SAME PART NUMBER OR WITH A N
EQUIVALENT PART IF REPLACEMENT BECOMES NECES-
SAR Y. DO NOT USE A REPLACEMENTPAR T OFLESSER QUAL-
ITY OR SUBSTITUTE DESIGN TORQUE VALUES MUST BE
USED AS SPECIFIED DURING REASSEMBL Y TO ASSURE
PROPER RETENTION OF THIS PAR T
CONTENTS OF THIS SECTION
Trouble Diagnosis and Testing
..............................
4C-1
Differential Case-Remove & Disassemble
..............
4C-4
Description
..............................................................
4C- 1
Drive Pinion
........................................................
4C-5
Operation
...............................................................
4C-2 Setting Pinion Depth 4C-6 ..............................................
Usage of "C" Differential
......................................
4C-3
Differential Case
-
Install
........................................
4C-9
Gear Ratios
..............................................................
4C-3 Side Bearing Shims 4C-9
..................................................
Axle Shaft, Bearing and Seal 4C-3
TROUBLE DIAGNOSIS AND TESTING
Trouble diagnosis and testing for the "C" type axle is the
same as described in Section 4A.
GENERAL DESCRIPTION
The type "C" is a semi-floating differential designed for an
open driveline and either leaf or coil springs. Its design is
similar but not identical to the standard differentials de-
scribed in Section 4A and 4B (Fig. 4C-1). The rear axle
wheel bearings consist of an outer race, 15 rollers and two
snap rings which retain the cage and rollers in the outer
race. The outer race and roller assembly is press fit in the
outer end of the rear axle tube at a predetermined depth
and is followed by the axle shaft seal. The axle shaft inner
splines engage the differential side gears with a floating fit.
The shaft has two machined and polished surfaces near ,
the flange end. One of these surfaces is a mating or sealing
surface for the axle seal and the other surface is the inner
race for the direct-on rear axle bearing. The axle shafts are
retained in the differential assembly by means of "C"
locks that are positioned in circular grooves machined
near the inner end of the axle shafts. When the axle shafts
and "C" locks are properly installed, the outer portion of
the "C" lock will be positioned in a machined recess in the
side gear which prevents removal of the "C" lock and the
axle shaft. The pinion shaft, when installed, prevents the
axle shaft from moving inward to release the
"C"
lock.
Pinion depth and backlash are calculated in a similar
manner to the standard differential. A different type col-
lapsible spacer is used. The spacer is longer and bears
against the inner races of both the front and rear pinion
bearings.
The car weight is carried on the axle shafts through the
roller bearings enclosed in the outer axle housing tubes.
Drive from the differential housing is transmitted to the
frame members through two upper and two lower control
arms which are designed to absorb vibration and noise.
The upper control arms are angle mounted to hold the