Chevrolet 1980 Light Duty Truck Repair Manual page 97

Fig. 1 8F--Removing Inner Pinion Bearing Cone and Roller
5. Check fit o f differential side gears in case.
6. Check fit o f side gears and axle shaft splines.
7. Inspect differential pinion shaft and spacer for
scoring or evidence o f excessive wear.
D IFF E R E N TIA L CASE
Reassem bly
1. Position differential side gears and new thrust
washers in differential case.
2. Position differential pinions and new thrust washers
in differential case. A lign pinions with holes in differential
case.
3. Install pinion shaft in differential case. A lign hole
in shaft with hole in case, then install lock pin. Peen hole
to prevent pin dropping out o f case.
4. Position ring gear to case, then install cap screws.
Tighten cap screws evenly and alternately to specifications.
5. W ith an arbor press, press differential side bearings
onto case using T ool J-21051. D o not install shim s at this
time.
Fig. 19F-C hecking Runout
REAR AXLE DIFFERENTIAL
6. Place differential case in carrier and install bearing
caps. Care should be taken to install caps in original
position. U se mark placed on caps and carrier at removal.
Tighten caps just enough to keep bearing caps in place.
7. Install dial indicator on carrier with indicator button
contacting back o f ring gear, as in figure 19F. R otate
differential case and check for runout. If runout is greater
than .002", the assem bly should be rem oved and the ring
gear rem oved from the case. A gain install differential case
and check runout at differential case flange.
8. Should runout o f case flange be greater than .002"
the defect is probably due to , bearings or differential case,
and should be corrected before proceeding further.
9. Position tw o screwdrivers between bearing cup and
carrier on opposite side o f ring gear (away from dial
indicator side). Pull on screwdrivers and force differential
case as far as possible toward the dial indicator. R ock the
ring gear to set the bearings. W ith force still applied, set
indicator at "O".
10. R eposition screwdrivers between bearing cup and
carrier on ring gear side. Pull on screwdrivers and force
differential case as far as possible toward center o f carrier.
Record the indicator reading. This will be the total am ount
o f shim s needed (less preload) for setting backlash later
during assembly.
11. R em ove differential from carrier.
D R IV E P IN IO N
In stalla tio n and A d ju s tm e n t of D epth and
Preload
R ing gears and pinions are supplied in m atched sets
only. M atching numbers on both pinion and ring gear are
etched for verification. If a new gear set is being used, verify
the numbers o f each pinion and ring gear before proceeding
w ith assembly.
On the button end o f each pinion there is etched a plus
( + ) number, a m inus ( - ) number, or a zero (0) number,
w hich indicates the best running position for each particular
gear set. This dim ension is controlled by the shim m ing
behind the inner bearing cup. W henever baffles or oil
slingers are used, they becom e a part o f the adjusting shim
pack.
For example: If a pinion is etched + 3 , this pinion
w ould require .003" less shim s than a pinion etched "0".
This means by rem oving shim s, the m ounting distance o f
the pinion is increased by .003" which is just what a +
etching indicates. 3 Or if a pinion is etched - 3 , we would
want to add .003" m ore shim s than w ould be required if the
pinions were etched "0". By adding .003" shim s, the
m ounting distance o f the pinion was decreased .003" which
is just what a - 3 etching indicated. See figure 20F.
If the old ring and pinion set is to be reused, m easure
the old shim pack and build a new shim pack to this sam e
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.
4B-29
O V E R H A U L M A N U A L