TM 9-2320-266-34
b. Install a dial indicator and position the contact point
against the back face of the ring gear. Move the differential
To prevent damage to the bearing, do not
and ring gear assembly tight against the drive pinion. Set
strike the bearing cage during installation.
the dial indicator on zero. Move the differential and ring
gear assembly in the opposite direction as far away from
(11) Install the drive pinion and bearing assembly in
the pinion as possible, and note the reading on the dial
the carrier.
indicator. This reading represents the shim pack thickness
(12) Install the original front bearing shim pack fol-
necessary to take up the clearance between the bearing cup
lowed by the front bearing cone.
and the case on the ring gear side of the differential
(13) Install the companion flange and nut. Tighten
assembly. Subtract this reading from the previously
the nut to 200-220 ft-lbs.
recorded total reading to obtain the amount of shims
necessary to take up the clearance between the bearing cup
(14) To check torque, rotate-the pinion shaft with
and the case at the pinion side of the differential.
an inch-pound torque wrench. The drive pinion must be
c. Remove the differential and ring gear assembly from
vertical for this check. The torque reading to start the shaft
the carrier.
turning will be disregarded. The torque reading while ro-
d. Remove the differential bearing cones. Install the
tating the shaft should be 20-40 in-lbs with new bearings,
correct thickness shim pack, determined in step b, between
or 10-20 in-lbs if the old bearings were used.
the bearing cone and the differential case hub shoulder
(15) Add or remove shims from behind the front
using tool C4025-A. Add an additional 0.015 inch shim to
bearing cone to obtain the correct (bearing preload) turning
the drive gear tooth side of the differential and install the
torque. Shims are available in the following thicknesses:
differential bearing cones. This additional 0.015 shim pack
0.003, 0.005, 0.010, and 0.030 inch.
provides the correct bearing preload and backlash.
(16) After the correct bearing preload has been estab-
e. Position spreader tool W-129-A in the locating holes
lished, pinion setting depth should be rechecked.
of the carrier and tighten the screw finger-tight. Install the
(17) Remove the companion flange and nut.
dial indicator and spread the carrier 0.015 to 0.020 inch.
Do not exceed this limit, or you won't be able to place the
(18) Install the oil slinger and gasket. Install a new
differential and ring gear assembly in the carrier.
oil seal. If the dust shield has been removed, install a new
dust shield.
f. Install the bearing caps in their respective positions as
indicated by the identification marks on the caps and
(19) Install the companion flange, washer, and nut.
carrier. Remove the spreader tool. Coat the bearing cap
Tighten the nut to 250-270 ft-lbs, holding the flange with
bolt threads with sealing compound and install and tighten
tool C-3281.
the bolts snugly.
(20) Turn the carrier and tube assembly in the hold-
g. Tap the drive gear lightly with a rawhide hammer to
ing fixture with the cover side facing upward. Install the
properly seat the differential bearing and cups. Take care
axle shaft inner oil seals.
to prevent nicking the teeth of the ring gear or drive pinion
19-3. (Deleted.)
as they are meshed together. Tighten the bearing cap bolts
to 70-90 ft-lbs.
19-4. Differential Bearing Preload and
h. Attach a dial indicator to the carrier. With the indi-
Drive Gear and Pinion Backlash.
cator contact point contacting the ring gear tooth (figure
a. With the
drive pinion and bearings installed and the
19-20), measure the backlash between the ring gear and
bearing preload set, install the differential case and ring gear
drive pinion.
assembly with their respective bearing cups. Install the
i. Check the backlash at four equally spaced points
bearing caps in their positions, aline identification marks,
around the circumference of the ring gear. The backlash
and tighten the cap bolts finger-tight. Refer to the measure-
must be held between 0.004 and 0.009 inch, and cannot
vary more than 0.002 inch between the four positions
reading, taken before the drive pinion was installed, repre-
checked. If backlash does not fall within these specifica-
sents the total clearance between the differential bearing
tions, change the shim pack thickness on both differential
cups and the carrier casting. Perform the following steps
bearing hubs to maintain proper bearing preload and back-
to determine the shim thicknesses required behind each
lash.
bearing cone to take up the clearance and establish the
correct bearing preload and backlash.
19-8
Change 1