Front Axle - GMC 1989 Light Duty Truck Repair Manual

SUBJECT
8 1 2
/ -lnch Ring Gear Front A x le ......................................................................................................................................... 4C1-1
9 3 4
/ -lnch Ring Gear Front A x le ......................................................................................................................................... 4C2-1
T Truck Front A x le ............................................................................................................................................................ 4C3-1
K Truck Front A x le ............................................................................................................................................................ 4C4-1
SUBJECT
Description................................................................................................
Disassembly of A x le .................................................................................................................................................................. 4 C 1 - 2
Inspection.................................................................................................................................................... ,
D isassem bly.................................................................................................................................................... ........................ 4 C 1 - 2
Cleaning and Inspectio n ............................................................................................................................... ...........................4C 1- 5
C le a n in g ........................................................................................................................................................... .........................4 C 1 - 5
Inspection........................................................................... ...................................................................................... * . .
Assembly of A xle.................................................................................................................................................. ...4 C 1- 6
Pinion Bearing Cup In s ta lla tio n ........................................................................................................................................4 C 1- 6
Pinion Depth A d ju s tm e n t............................................................................................................................................. .... .4 C 1- 6
Pinion In s ta lla tio n .................................................................................................................................................................. 4 C 1 - 7
Differential Case A ssem bly.................................................................................................................................................. 4 C 1 - 7
Side Bearing Preload A d ju s tm e n t.................................................................................................................................... 4 C 1 - 9
Backlash A djustm ent........................................................................................................................................................... .4C 1-10
Gear Tooth Contact Pattern C h e c k ................................................................................................................................"!4C1-11
Final A ssem bly.........................................................................................................................................................................4C 1 -1 2
S p e c ific a tio n s ............................................................................................................................................................................. 4C 1 -1 3
Special T o o ls ................................................................................................................................................................................4C 1 -1 4
DESCRIPTION
8 1 2
T h e GM / -in c h rin g g e a r fro n t a xle u ses a
coventional ring gear and pinion gear set to transm it the
driving force of the engine to the 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 shafts are retained in the
housing by retaining clips in the hubs.
The pinion gear is supported by two tapered roller
bearings. The pinion depth is set by a shim pack located
bwtween the gear end of the pinion and the roller bearing
SECTION 4C

FRONT AXLE

CONTENTS
SECTION 4C1
8V2-INCH RING GEAR
CONTENTS
DESCRIPTION
^ ^
................................................................................ 4 C 1 - 1
that is pressed onto the pinion. The pinion bearing
preload is set by crushing a collapsible spacer between
the bearings in the axle housing.
The ring gear is bolted onto the differential case with
left-hand thread bolts.
The differential case is supported in the axle housing
by two tapered roller bearings. The differential and ring
gear are located in relationship to the pinion by using
selective shim s betw een the bearing and the axle
housing. To move the ring gear, shims are deleted from
one side and an equal amount area added to the other
side. These shims are also used to preload the bearings,
4C1-1
PAGE
PAGE
...................... 4C 1 - 2
. . .4C1 - 5