GMC 1989 Light Duty Truck Repair Manual page 255

93/4-INCH r in g g e a r f r o n t
S U B J E C T
D escription.................................................................................................................................................................................... 4C 2- 1
Disassembly of A x le .................................................................................................................................................................. 4 C 2 - 2
Inspection..................................................................................................................................................................................4 C 2 - 2
D isassem bly............................................................................................................................................................................. 4 C 2 - 2
Cleaning and Inspectio n ........................................................................................................................................................... 4C 2- 7
C le a n in g .................................................................................................................................................................................... 4C 2- 7
Inspection..................................................................................................................................................................................4 C 2 - 7
Assembly of A xle.........................................................................................................................................................................4C 2- 8
Differential Case A ssem bly.................................................................................................................................................. 4C 2- 8
Determining Total Differential Shim Pack S iz e ............................................................................................................. 4 C 2 - 9
Pinion Depth A d ju s tm e n t.................................................................................................................................................... 4C 2- 9
Pinion In s ta lla tio n .................................................................................................................................................................. 4C2-11
Assembling the Differential Housing to the Axle Housing.........................................................................................4C 2-13
Checking Backlash..................................................................................................................................................................4C 2-14
Final A ssem bly.........................................................................................................................................................................4C 2-14
S p e c ific a tio n s ............................................................................................................................................................................. 4C 2-15
Special T o o ls ............................................................................................................................................................................... 4C 2-16
The Dana 93/4-inch ring gear front axle uses a conven­
tional ring and pinion gear set to transm it the driving force
of the engine to the front wheels. This gear set transfers
this driving force at a 90 degree angle from the propeller
shaft to the drive shafts.
The pinion gear is supported by two tapered roller bear­
ings. The pinion depth is set by a shim pack between the
inner pinion bearing cup and the front axle housing. The
pinion bearing preload is set by a shim pack at the front of
the axle housing between the yoke and the pinion gear.
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 selective
shims between the bearings and the differential case. To
move the ring gear, shims are deleted from one side and
an equal amount are added to the other side. Differential
SECTION 4C2
CONTENTS
DESCRIPTION
side bearing preload is set by the axle housing. (The axle
housing is spread to remove the differential from the
housing.) When the spreader is removed, the housing
sets the bearing preload.
Two bearing caps are used to hold the differential into
the front axle housing.
The differential is used to allow the wheels to turn at
different rates of speed while the front axle continues to
transmit the driving force. This prevents tire scuffing when
going around corners and prevents premature wear on
internal axle parts.
The front axle is sealed with a pinion seal, an axle seal,
and RTV sealer between the differential cover and front
axle housing.
All Dana axles are identified by the part number located
on the right axle tube next to the manufacturing date
which is next to the carrier. The carrier cover does not
have a drain plug. Oil is drained by removing the cover.
4C2-1
a x l e
P A G E