Chevrolet 1980 Light Duty Truck Repair Manual page 132

4C-6 FRONT WHEEL DRIVE
O ld P in ion
M a rk in g
- 4
+ 4 + 0 .0 0 8
+ 3 + 0 .0 0 7
2
+ + 0 .0 0 6
1
+ + 0 .0 0 5
0
+ 0 .0 0 4
1
- + 0 .0 0 3
2 0 .0 0 2
- +
0 .0 0 1
- 3 +
0
- 4
For example: If a pinion is etched + 3 , this pinion
would require .003" less shim s than a pinion etched "0".
This m eans by removing shim s, the m ounting distance o f
the pinion is increased by .003" which is just what a + 3
etching indicates. Or if a pinion is etched - 3 , we w ould want
to add .003" more shims than would be required if the
pinions were etched "0". By adding .003" shims, the
m ounting distance o f the pinion was decreased .003" which
is just what a - 3 etching indicated.
If the old ring and pinion set is to be reused measure
the old shim pack and build a new shim pack to this same
dim ension. If baffle is in the axle assembly, it is considered
as part o f the shim pack.
To change the pinion adjustment, shim s are available
in thicknesses o f .003", .005" and .010".
If baffle or slinger is bent or m utilated, it should be
replaced.
Measure each shim separately with a m icrometer and
add together to get total shim pack thickness from original
build up.
If a new gear set is being used, notice the plus or m inus
etching on both the old and new pinion, and adjust the
thickness o f the old shim pack to com pensate for the
difference o f these two figures.
For example: If the old pinion reads + 2 and the new
pinion is - 2 , add .004" shim s to the original shim pack.
1. Determ ine proper inner shim pack (for setting
pinion depth) by using chart (Fig. 4C-9).
2. Install inner shim pack and oil slinger in inner cup
bore and drive inner cup into position using T ool J -2 1059
used with J-8092.
3. T o the outer shim pack (for setting preload) add or
remove an equal amount as was added or removed from the
inner shim pack.
4. Install outer cup in carrier bore, using installer J-
7818 with D rive Handle J-8092.
5. Press inner pinion bearing cone and roller onto
pinion shaft using Installer J-9772 on arbor press as shown
in Figure 4C-10.
N e w
2 1
- 3 - -
+ 0 .0 0 7 + 0 .0 0 6 + 0 .0 0 5
+ 0 .0 0 5 + 0 .0 0 4
+ 0 .0 0 6
+ 0 .0 0 5 + 0 .0 0 4 + 0 .0 0 3
0 .0 0 2
+ 0 .0 0 4 + 0 .0 0 3 +
0 .0 0 2 0 .001
+ 0 .0 0 3 + +
0 .0 0 1
0 .0 0 2 0
+ +
0 0 .0 0 1
0 .0 0 1 -
+
0 0 .0 0 1 0 .0 0 2
- -
0 .0 0 2
0 .0 0 1
- - - 0 .0 0 3
F ig . 4 C - 9 ~ D r iv e P in io n S h im C h a r t
P in io n M a rk in g
1 2
0 + +
0 .0 0 2
+
+ 0 .0 0 4 + 0 .0 0 3
0 .002 0 .0 0 1
+ +
+ 0 .0 0 3
0 .0 0 2 0 .0 0 1 0
+ +
0 .0 0 1 0 0 .0 0 1
-
+
0 .0 0 1 0 .0 0 2
0 - -
0 .0 0 1 0 .0 0 2
- - 0 .0 0 3
-
0 .0 0 2
- - 0 .0 0 3 - 0 .0 0 4
- 0 .0 0 3 - 0 .0 0 4 - 0 .0 0 5
- 0 .0 0 4 - 0 .0 0 5 - 0 .0 0 6
6. Install drive pinion and inner bearing cone and
roller assembly in differential carrier.
7. Install shim s and outer pinion cone and roller on
pinion shaft using Tool J-5590 and com panion flange to
press bearing onto pinion (Fig. 4C -11).
8. Install flange holding bar and install washer and nut
on pinion shaft. Torque nut to 255 ft. lbs.
9. R em ove holding bar and with an inch pound torque
wrench measure rotating torque. R otating torque should be
10 to 20 in. lbs. with original bearings or 20 to 40 in. lb.
with new bearings.
Torque reading to
disregarded.
10. If torque requirements
specifications, adjust shim pack as necessary Increase the
outer shim pack to reduce rotation torque. D ecrease shim
pack to increase rotating torque.
11. R em ove nut, washer and flange from pinion shaft.
12. Install oil slinger, gasket and using T ool J-22804
install oil seal.
13. Install flange, washer and nut. Torque nut to
specifications.
+ 4
+ 3
0 .0 0 1 0
+
0 0 .0 0 1
-
0 .0 0 1 0 .0 0 2
- -
0 .0 0 2
- - 0 .0 0 3
- 0 .0 0 3 - 0 .0 0 4
*
- 0 .0 0 4 - 0 .0 0 5
- 0 .0 0 5 - 0 .0 0 6
- 0 .0 0 7
- 0 .0 0 6
- 0 .0 0 7 - 0 .0 0 8
start shaft turning must
(preload) are not
O V E R H A U L M A N U A L
be
to