GMC 1989 Light Duty Truck Repair Manual page 177

S U B J E C T
D escrip tion ............................................................................................................................................................................... 4 B 4 - 1
Checking the Axle Before Disassembly........................................................................................................................... 4 B 4 - 1
Disassembly of the Rear A xle............................................................................................................................................. 4B 4- 2
C le a n in g ....................................................................................................................................................................................4B 4- 2
Inspection..................................................................................................................................................................................4 B 4 - 2
Assembly of the Rear A x le ..................................................................................................................................................4 B 4 - 5
Gear Tooth Pattern C h e c k ..................................................................................................................................................4 B 4 - 9
Adjustments Affecting Tooth C ontact..................................................................................................................................4 B 4 - 9
S p e c ific a tio n s ............................................................................................................................................................................. 4B4-11
Special T o o ls ............................................................................................................................................................................... 4B 4-12
DESCRIPTION
101 2
The corporate / -inch ring gear rear axle uses a
conventional ring and pinion gear set to transmit the
driving force of the engine to the rear wheels. This gear
set transfers this driving force at a 90 degree angle from
the propeller shaft to the drive shafts.
This axle is full-floating. The axle shaft is supported at
the wheel ends by the wheel hubs. The bolts that attach
the shaft to the hub, support the axle at the hub. The
splined end of the shaft is supported by the differential.
The pinion gear is supported in a pinion cage by three
bearings: a pinion front bearing, a pinion rear bearing,
and pilot bearing. The pinion cage is separate from the
axle housing. Selective shims are used between the
pinion cage and the axle housing to set the pinion depth.
T he p in io n b e a rin g p re lo a d is set by c ru s h in g a
collapsible spacer between the front and rear bearings in
the pinion cage.
The ring gear is bolted onto the differential case with
left-hand thread bolts.
The differential case is supported in the case by two
tapered roller bearings. The differential and ring gear are
located in relationship to the pinion by using two different
bearing adjusting nuts. These allow the differential to be
moved from side to side by adjusting the nuts in or out.
The differential side bearing preload is accomplished by
tightening the differential bearing adjusting nuts after the
ring gear backlash has been set. Two bearing caps are
used to hold the differential into the rear axle housing as
well as to supply half of the threads for the bearing
adjusting nuts.
SECTION 4B4
101/2-INCH RING GEAR
CONTENTS
1Q1/2-INCH RING GEAR 4B4-1
The differential is used to allow the wheels to turn at
different rates of speed while the rear axle continues to
transmit the driving force. This prevents tire scuffing when
going around corners and prevents premature wear on
internal axle parts.
The rear axle is sealed with a pinion seal, a gasket at
each axle shaft end, and by a gasket between the rear
cover and the axle housing.
All corporate rear axles are identified by the part
number on the right axle tube near the carrier. The carrier
cover does not have a drain plug.
CHECKING THE AXLE
BEFORE DISASSEMBLY
!?
Inspect
Remove the axle cover from the rear axle and drain the
axle lubricant into a suitable container.
1. R in g g e a r b a c k la s h .
Adjustm ent" in this section. This information can be
used to determine the cause of the axle problem. It
will also help when setting up the shim packs for
locating and preloading the differential case.
2 . Case for metal chips and shavings. Determine
where these chips and shavings come from; such as
a broken gear or bearing cage.
Determ ine the cause of the axle problem before
disassembly if possible.
P A G E
R e fe r to " B a c k la s h