Effects Of Backlash On Tooth Pattern; Effects Of Pinion Position On Tooth Pattern; Overhaul Differential; Differential Case - Pontiac Grand Prix Service Manual

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4A-14
1969
PONTIAC SERVICE MANUAL
>
HEEL HEEL
DRIVE SIDE COAST SIDE
(CONVEX) (CONCAVE)
.
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Fig. 4A-18 Tooth Pattern
-
Insufficient Backlash
however, these adjustments should be within specifica-
tions before proceeding with backlash and drive pinion
adjustments.
Backlash is adjusted by means of the side bearing
adjusting shims which move the entire case and ring
gear assembly closer to, or farther from, the drive
pinion. (The adjusting shims are also used to set side
bearing preload.)
The position of the drive pinion is adjusted by
increasing, or decreasing the shim pack between the
ness will move the pinion closer to centerline of the
ring gear; decreasing shim pack thickness will move
pinion farther away from centerline of the ring gear.
EFFECTS OF BACKLASH ON TOOTH PATTERN
The terms "excessive" and "insufficient" refer to
settings which are greater than .009" or less than .005"
as specified. With respect to tooth contact patterns,
"excessive" refers to backlash which, although less
than .009", is more than necessary to provide the
desired pattern. Similarly, "insufficient" refers to
backlash which, although .005" or more, is less than
necessary to provide the desired pattern.
Provided the pinion is properly positioned, excess
backlash will give a high heel pattern on both drive
and coast sides (Fig. 4A- 17). Decreasing backlash by
moving the case and ring gear assembly closer to the
pinion will cause the pattern to move toward the toe
end and down toward center of the tooth on both drive
and coast sides.
Insufficient backlash, provided the pinion is properly
positioned, will give a low toe pattern on both drive
and coast sides (Fig. 4A-18). Increasing backlash will
cause the pattern to move toward the heel end and up
toward top of the tooth on both drive and coast sides.
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EFFECTS OF PINION POSITION ON TOOTH
I
PATTERN
When the drive pinion
a
too far away from centerline
of the ring gear, the pattern will be a high heel contact
TOE
DRIVE SIDE COAST SIDE
(CONVEX) (CONCAVE)
Fig. 4A-19 Tooth Pattern
-
Pinion Too Far Away From
Ring Gear (Shim Thickness Insufficient)
".
\.
.,,
DRIVE SlDE
COAST StDE
(CONVEX) (CONCAVE)
Fig. 4A-20 Effect on Pattern
-
As Shim Thickness is
Increased
on drive side and a high toe contact on coast side (Fig.
4A-19), provided backlash is within specifications of
.005"
to ,009". Moving the pinion closer to center line
of the ring gear by increasing shim pack thickness will
cause the high'heel contact on drive side to lower and
move toward the toe; the high toe contact on coast side
will lower and move toward the heel (Fig. 4A-20).
When the pinion is too close to the ring gear, the
pattern will be a low toe contact on drive side and a
low heel contact on coast (Fig. 4A-21), provided
backlash is within specifications of .005" to .009".
Moving the pinion farther away from the ring gear by
decreasing shim pack thickness will cause low toe
contact on drive side to raise and move toward the
heel; low heel contact on coast will raise and move
toward the toe (Fig. 4A-22).
OVERHAUL DIFFERENTIAL
DIFFERENTIAL CASE
REMOVE
NOTE:
Before removing case from housing, be sure the