GMC 1989 Light Duty Truck Repair Manual page 303

Figure 31— Measuring Backlash at the Ring Gear
1. Refer to figures 1 through
2. Tighten the right sleeve (32) to 140 N-m (100 ft. lbs.).
Use J 36599 (figure 28).
3. Tighten the left , sleeve (32) (K15-25 models) or
adjuster plug (61) (K35 models) to 140 N-m (100 ft.
lbs.).
• Use J 36599 (K15-25 models) (figure 28).
• Use J 36615 (K35 models) (figure 29).
4. Mark the location of the adjusting sleeves in relation
to the carrier halves, so the notches in the adjusting
sleeves can be counted when turned.
5. Turn the right sleeve OUT two notches.
6
. Turn the left sleeve (K15-25 models) or adjuster plug
(K35 models) IN one notch.
7. Rotate the pinion several times 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 must be held stationary when
checking backlash.
• The backlash should be the same at each
point w ithin 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 (0.003-0.010 in c h ) w ith a p re fe rre d
J 8001-1
F-5874
4.
m ore th a n 0.05 mm
K TRUCK FRONT AXLE 4C4-15
Figure 32— Measuring Backlash at the Pinion Flange
s p e c ific a tio n
(0.005-0.007-inch).
• If the backlash is incorrect, adjust the sleeves
as necessary. Alw ays m aintain 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).
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 differential carrier. Record the dial
indicator reading.
5. DIVIDE THE DIAL INDICATOR READING BY 2 to
obtain the actual backlash when using this method.
F-5875
of 0.13-0.18 mm