Gear Tooth Contact Pattern C H E C - Chevrolet 1988 Light Duty Truck Repair Manual

4C4-14 K TRUCK FRONT AXLE
Figure 31 — Measuring Backlash at the Ring Gear
7. Rotate the pinion several tim es to seat the bearings.
8. Install J 34047-3 into the filler plug hole. Install
J 34047-1 and J 8001-1 as shown in figure 31.
9. Place the indicator stem at the heel end of a tooth.
10. Check and record the backlash at three or four
points around the ring gear.
• The pinion m ust be held stationary when
checking backlash.
• The backlash should be the same at each
p o in t w ith in 0.05 mm (0.002-inch). If the
b a c k la s h v a rie s
(0.002-inch), check for burrs, a distorted case
flange, uneven bolting conditions, or foreign
matter between the case and the ring gear.
• Gear backlash should be between 0.08-0.25
mm (0 .0 0 3 -0 .0 1 0 in c h ) w ith a p re fe rre d
s p e c ific a tio n
(0.005-0.007-inch).
• If the backlash is incorrect, adjust the sleeves
as n e cessary. A lw ays m a in ta in the " one
notch" preload on the side bearings. Example:
If it is necessary to turn the RIGHT sleeve IN
one notch, the LEFT sleeve must be turned
OUT one notch.
• To increase backlash, turn the left sleeve in,
and turn the right sleeve out an indentical
amount. To decrease backlash, turn the right
sleeve in and turn the left sleeve out an
identical amount.
• Changing the sleeves one notch will change
backlash about 0.08 mm (0.003-inch).
J 8001-1
F-05874
m o re th a n 0.05 mm
o f 0 .13-0.18 mm
Figure 32— Measuring Backlash at the Pinion Flange
MEASURING BACKLASH (ALTERNATE METHOD)
1. Use this method if the tools specified previously are
not available.
2. If the specified tools are not available, it is possible
to read backlash at the pinion flange, as follows:
3. Install a dial indicator so the button contacts the
outer edge of the pinion flange. The plunger must
be at a right angle to the pinion flange (figure 32).
4. Move the pinion flange through its free play while
holding the d iffe re n tia l carrier. Record the dial
indicator reading.
5. DIVIDE THE DIAL INDICATOR READING BY 2 to
obtain the actual backlash when using this method.
Example: A dial indicator reading of 0.16 mm means
that there is actually 0.08 mm backlash.
6. Follow the steps for adjusting backlash outlined
previously.
GEAR TOOTH CONTACT
PATTERN CHECK
Before final assembly of the differential, a gear tooth
contact pattern check should be performed.
It should be noted that a gear tooth contact pattern
check is NOT a substitute for adjusting pinion depth and
backlash as previously outlined. It is a final check to verify
the correct running position of the ring gear and the drive
pinion. Gear sets which are not positioned properly may
be noisy, or have a short life, or both. With a pattern
F-05875