GMC 4000 Series Service Manual page 138

in "REAR HUBS AND BEARINGS" (SEC. 4C). Roll
axle into position under vehicle.
3. Connect springs to axle as directed in
"REAR SPRINGS" (SEC. 4B).
4. Reconnect the torque rods as directed in
"REAR SPRINGS" (SEC. 4B). On some vehicles
torque rods are adjustable to secure proper axle
alignment.
5. Reconnect propeller shafts as directed in
"PROPELLER SHAFTS" (SEC. 4D).
6. Reconnect electric wiring or line at shift
chamber if vehicle is equipped with a 2-speed axle.
7. Reconnect air brake lines as directed in
BRAKES (SEC. 5).
8. Check lubricant level and fill with type and
of in the
g rad e lu brican t
LUBRICATION (SEC. 0). Some types of axles re­
quire additional lubricant at pinion cage when filled
initially or after overhaul.
9. Remove blocks and lower vehicle to the
ground. Retighten spring U-bolts as instructed in
"REAR SPRINGS" (SEC. 4B).
10. After all installation procedures have
been completed, check air or vacuum lines for
leaks, also test brakes for proper application.
DIFFERENTIAL CARRIER
REPLACEMENT
In some instances it may be desirable to r e ­
move the differential carrier assembly from the
axle housing, while the housing remains installed
under the vehicle.
To assist in handling the differential carrier
assembly, a roller jack should be available; also,
a pan for draining lubricant.
Inspect axle housing for lubricant leaks before
cleaning, then steam clean thoroughly to remove
all dirt or other foreign matter.
REMOVAL
1. Remove plug at bottom of housing to drain
lubricant.
2. Remove axle shafts as directed under head­
ing "Axle Shaft Replacement" in this section.
3. On 2-speed axles disconnect lines from
shift chamber or wiring from shift electric unit.
4. Disconnect propeller shaft from yoke as
directed in "PROPELLER SHAFTS" (SEC. 4D).
5. Remove cap screws or stud nuts, and lock
washers, except two near top. Loosen two at top
and leave installed to prevent carrier falling.
6. Support carrier on roller jack, remove top
stud nuts or cap screw s, then work carrier free
of housing. A small pinch bar may be used to keep
carrier straight in housing bore, while carrier is
withdrawn. End of bar must be rounded to prevent
damage to carrier flange.
G M C S E R V I C E M A N U A L
in
m anner in stru cted
REAR AXLE AN D CONTROLS
INSTALLATION
1. Install new differential carrier to housing
gasket over studs or align bolt holes in gasket with
holes in housing. On axles using cap screw s, in­
stall four temporary studs which will simplify
locating carrier and gasket and a ssist in drawing
carrier into place.
2. Roll carrier into place using roller jack.
Start carrier over studs and into housing, using
flat washers under four equally spaced stud nuts.
3. Tighten all nuts evenly and alternately until
carrier is in position. Replace temporary flat
washers. Install lock washers, then tighten all nuts
to specified torque.
4. Connect propeller shaft to rear axle yoke
as directed in
"PROPELLER SHAFTS" (SEC.
5. On 2-speed axles connect wiring to electric
shift unit or line to shift chamber.
6. Install axle shafts as directed under head­
ing "Axle Shaft Replacement" in this section.
7. Fill to level of filler plug opening with lub­
ricant recommended in LUBRICATION (SEC. 0) of
this manual.
AXLE SHAFT REPLACEMENT
REMOVAL
Procedure for removal of axle shafts is the
same with axle assembly removed or installed in
the vehicle.
1. Remove nuts from studs attaching axle
shaft flange to wheel hub.
2. Strike center of flange with a lead hammer
to loosen flange and split tapered dowels from
studs.
3. Remove split tapered dowels from studs.
In some instances it may be necessary to spread
dowels, while being removed.
4. Grasp axle shaft flange and pull outward to
remove. Remove and discard gasket.
INSTALLATION
1. Install new gasket over hub studs and
against hub.
2. Dip splined end of shaft in axle lubricant,
and insert shaft through hub.
3. Turn shaft as necessary to index shaft
splines with differential side gear splines.
4. As shaft is pushed inward, rotate as nec­
essary to align flange holes with hub studs, then
press shaft inward until flange is against hub.
5. Install split tapered dowel over each stud.
Install and tighten 5/8" nuts to 90-110 foot-pounds
torque or 1/2" nuts to 50-60 foot-pounds torque.
6. Observe that clearance exists between nut
and flange (fig. 6). If no clearance exists, this in­
dicates excessive wear at studs, dowels, or flange
holes. Replace worn parts if necessary.
Sec. 4A
Page 131
4D).