TM 5-3825-226-24
DIFFERENTIAL AND CARRIER ASSEMBLY (LOCK TYPE)
28.
To make an adjustment of the differential bearing
preload and gear clearance (backlash) between the
bevel gear and pinion use the following procedure:
a)
Tighten the adjustment nuts until there is a
small amount of preload on the bearings.
b)
Install tool group (C) on the bevel gear as
shown
to
check
the
gear
clearance
(backlash) at four locations around the bevel
gear 90° apart. Use the lowest indication on
tool group (C) as the correct gear clearance
(backlash) value. The correct gear clearance
(backlash) is .010 + .004 or-.003 in. (0.25 +
0.10 or -0.08 mm).
c)
If the gear clearance (backlash) is too much,
loosen the upper adjustment nut and tighten
the lower adjustment nut the same amount to
change to gear clearance (backlash) If the
gear clearance (backlash) is not enough,
loosen the lower adjustment nut and tighten
the upper adjustment nut the same amount
to change the gear clearance (backlash).
d)
Tighten the upper adjustment nut until a
torque of 30 to 50 lb. in. (3.4 to 5.7 N•m) is
needed to turn the pinion shaft.
e)
Check the gear clearance (backlash) again
as in Steps b and c.
29.
To check the tooth contact setting between the
bevel gear and pinion after the gear clearance
(backlash) and the bearing preload adjustments
have been made, use the following procedure:
a)
Put small amount of prussian blue, red lead
or paint on bevel gear teeth. Turn pinion and
check marks made on bevel gear teeth.
b)
With no load, correct tooth contact setting
will be as shown. The area of contact starts
near toe of gear and goes about 30% up the
length of tooth. With this setting when load
is put on gear, it will be over the correct area
of teeth.
c)
If bevel pinion shaft is too far away from
bevel gear, short toe contact will result as
shown. The teeth of pinion will be in contact
with toe ends of convex faces (part that
makes a curve toward the outside), and top
edge of heel end of concave faces (part that
makes a curve toward the inside). To correct
this, move pinion shaft toward gear by a
decrease of shim thickness between pinion
cage and carrier. After this is done, check
gear clearance (backlash) and tooth contact
again.
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