Pontiac FIREBIRD 1972 Service Manual page 377

TYPE C STANDARD DIFFERENTIAL 4C-9
12. Examine ring gear and pinion. Nicks, burrs, or scor-
ing will require replacement of gear set.
13. Slide a new collapsible spacer on the pinion shaft,
(Fig. 4C-18) position pinion assembly in carrier and
install front pinion bearing onto pinion shaft using
installer J-22836.
14. Coat cavity between pinion oil seal lips with front
wheel bearing grease and install the seal into the
carrier bore using Installer J-22836 and Spacer J-
22804-1 (all A and G Series) Installer J-22388 (B and
F Series), or Installer J 2391 1 and Spacer J 22804-2
(X Series). The spacer is not required in installing the
seal in B or F Series axles. Rotate spacer occasionally
to insure that seal is not slanted in carrier bore. See
Fig. 4C-19.
15. Install pinion flange and flange holder J-8614-10.
16. Pack the cavity between the end of the pinion splines
and the pinion flange with a nonhardening sealer
(such as Permatex type A or equivalent).
17. Install washer and new self-locking pinion nut on
pinion. Tighten nut to remove pinion end play. When
end play is removed, alternately tighten nut and
check pinion preload until a torque of 20-25 1b.in is
required to rotate the pinion with new bearings and
seal installed or 10-15 1b.in. when used parts are rein-
stalled. See Fig. 4C-20.
DIFFERENTIAL CASE
INSTALL
Differential side bearing preload is adjusted by changing
the thickness of both the right and left shims by an equal
amount.
Fig. 4 C - 2 0 Checking Pinion Preload
By changing the thickness of both shims equally, the origi-
nal backlash will be maintained. All differential side bear-
ing preload shims used in production are cast. Shims used
during service repairs of the differential are of a stamped
steel design and are used along with a production type,
.160"
+
or
-
.001" thick, cast spacer. Stamped steel ser-
vice shims must be used when differential repairs are made
that require removal of the case assembly.-service, steel,
adjusting shims are available in thickness ranging from
.032" to .064" in increments of .002".
1. Before installation of case assembly, make sure that
side bearing surfaces in carrier are clean and free of
burrs. Side bearings must be oiled with gear lube. If
same bearings are being reused, they must have origi-
nal outer races in place.
2. Achieve a slip fit between the carrier and the side
bearings as follows:
NOTE:
A slip f i t means zero pre-load, or the
point at which bearings have no play and no
drag. A t this point, in and out movement of the
case is possible but side to side movement is not.
a. Use a micrometer to measure production shims,
and subtract .004" from each reading. Do not mix
the left and the right shims.
5-22836(A AND G SERIES)
5-22838(B AND F SERIES)
-
I
b. Using a service spacer (. 170") and service shims,
make up a shim pack for each side equal to the
thickness of the original shim minus .004" and
install as shown in Fig. 4C-2 1 (flat edge of spacer
against housing). This will duplicate the original
setting minus pre-load.
c. If this does not provide a proper slip fit, spacers
must be added or removed equally from both
sides as necessary.
d. Install side bearing caps as previously marked,
and tighten bolts to 70 lb. ft. Check backlash and
do red lead test before adding side bearing pre-
load.
Fig. 4C-19 Installing Pinion Oil Seal
3. Rotate differential case several times to seat bearings,
then mount dial indicator as shown in Fig. 4C-22.