GMC PD-4103 Maintenance Manual page 16

GM COACH MAINTENANCE MANUAL
Sec, 2
Page 17
Rear axle is full-floating type, using a one
piece axle housing with housing bowl cover welded
to housing. Housing bowl is located to the left of
axle center line.
As shown in figure 3, drive pinion assembly
is mounted at an angle to drive gear, thus in-
creasing the tooth contact area between drive gear
and drive pinion gear teeth. Drive is transmitted
from transmission angle drive unit through pro-
peller shaft to spiral bevel gears, axle housing,
and springs, then to vehicle underframe.
Differential and drive pinion assemblies are
both provided with facilities for adjustment of
bearings and gear tooth contact.
DIFFERENTIAL CARRIER
Differential assembly, drive pinion, and pm10n
cage assembly, are mounted in differential car"rier.
After axle shafts have been removed, and propeller
shaft has been disconnected, differential carrier
can be removed for inspection and adjustment
without removing axle housing from vehicle.
DIFFERENTIAL ASSEMBLY
Conventional four-pinion type differential is
carried in two-piece case mounted on tapered
roller bearings. Bevel drive gear is bolted to
flanged half of differential case. Drive gear and
pinion are furnished in matched, lapped sets, and
should always be installed as such to assure sat-
isfactory operation.
Thrust washers are used between differential
side gears and case and between differential pin-
ions and case. Each pinion contains an aluminum-
bronze bushing. When bushings become worn, pin-
ions must be replaced. Differential case halves
are held together with special bolts and slotted
nuts, locked in place with lock wire.
DIFFERENTIAL SIDE BEARINGS
Differential case is supported in tapered roller
bearings which take thrust as well as radial loads.
Bearings are mounted in machined supports in
differential carrier with thrust loads taken by ad-
justing rings threaded into carrier supports and •
bearing caps. Adjusting rings bear against bearing
cups and are locked in position by adjusting ring .
locks bolted to each bearing cap.
PINION AND CAGE ASSEMBLY
Bevel drive pinion is installed at an angle in
differential carrier. Pinion is straddle mounted
in two opposed tapered roller bearings at outer
end, and one straight roller bearing at inner end.
Tapered roller bearing cups are installed in
pinion cage (fig. 3), and are separated by a ma-
chined shoulder in pinion cage assembly.
Pinion bearings are adjusted on shaft by se-
lecting correct spacer combination as described
later in this section, under "Pinion and Cage As-
sembly."
Straight roller bearing at inner end of drive
pinion, is secured in place with retainer and a bolt.
Shims of various thicknesses are used between
bearing cage and differential carrier to adjust
drive pinion tooth contact and gear backlash.
Pinion shaft and cage assembly cannot be re-
moved from carrier until differential case assem-
bly including drive gear has been removed from
carrier.
AXLE SHAFT AND HOUSING
Axle shafts are full floating type. Drive flange
at outer ends have external teeth which mesh with
similar internal teeth on hub drive plate. Drive
plate is doweled to hub with dowel pins and held
in place, together with plate cover, with ten hub
studs and nuts as illustrated in figure 1.
Axle housing is one-piece design with differ-
ential located off center. Housing is equipped with
removable outer end tubes which are threaded to
accommodate wheel bearing adjusting nuts.
AXLE MAINTENANCE ON VEHICLE
The following maintenance operations should be
accomplished at regular inspection and lubrication
intervals.
LUBRICATION
Lubrication intervals, method of filling and
draining, also type of lubricant for axle is covered
in LUBRICATION (SEC. 13).
Check for lubricant leaks at differential hous-
ing, at pinion bearing oil seal and at cover plate
at outer end of hubs. Eliminate leaks by tightening
nuts or bolts or by replacing gaskets or oil seal.