GMC S Series 1994, Руководство по ремонту

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Figure 26— Measuring Backlash at the Pinion
Flange
10. Check and record the backlash at three or four
points around the ring gear.
• The pinion must be held stationary when check­
ing backlash.
• If the backlash varies more than 0.05 mm
(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 to 0.25
mm (0.003 to 0.010 inch) with a preferred spec­
ification of 0.013 to 0.018 mm (0.005 to 0.007
inch).
• If the backlash is incorrect, adjust the sleeves
as necessary. A lw ays m aintain 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 the right sleeve out, an identical amount.
To decrease backlash, turn the right sleeve in,
and the left sleeve out, an identical amount.
11. When the backlash is correct, mark the position of
the sleeves so they can be kept in the same location.
GEAR TOOTH CONTACT
PATTERN CHECK
Before final assembly of the differential, a gear tooth
contact pattern check should be performed.
A gear tooth contact pattern check is NOT a substi­
tute for adjusting pinion depth and backlash as previ­
ously outlined. It is a method to verify the correct
running position of the ring gear and the drive pinion.
Gear sets which are not positioned properly may be
noisy, have a short life, or both. With a pattern check,
the best contact between the ring gear and the drive
pinion for low noise level and long life can be ensured.
GEAR TOOTH NOMENCLATURE
The side of the ring gear tooth which curves outward,
or is convex, is referred to as the “drive” side. The
concave side is the “coast” side. The end of the tooth
nearest the center of ring gear is referred to as the
“toe” end. The end of the tooth farthest away from the
center is the “ heel” end. The toe end of the tooth is
smaller than the heel end (figure 27).
TEST
1. Wipe oil out of axle housing and carefully clean
each tooth of the ring gear.
2. Apply gear marking compound sparingly to all
ring gear teeth using a medium stiff brush.
3. Use the service brake to apply a load until a
torque of 54-68 N-m (40-50 lbs. ft.) is required
to turn the pinion.
A test made without loading the gears will not
give a satisfactory pattern. Turn the companion
flange with a wrench so that the ring gear
rotates one full revolution. Then reverse the
rotation so that the ring gear rotates one revolu­
tion in the opposite direction. Excessive turning
of the ring gear is not recommended.
4. Observe the pattern on the ring gear teeth and
compare with figure 28.
ADJUSTMENTS AFFECTING TOOTH CONTACT
Two adjustments can be made which will affect the
tooth contact pattern. These are backlash and pinion
depth. The effects of bearing preloads are not easily
seen on hand loaded teeth pattern tests. These adjust­
ments should be within specifications before proceeding
with the backlash and the drive pinion adjustments.
It may be necessary to adjust both pinion depth and
backlash to obtain the correct pattern.