REAR AXLE - 226RIA
TABLE OF CONTENTS
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REAR AXLE - 226RIA
DESCRIPTION .........................11
OPERATION ...........................11
DIAGNOSIS AND TESTING - REAR AXLE .....11
STANDARD PROCEDURE - DRAIN AND
REFILL .............................14
REMOVAL .............................15
INSTALLATION .........................15
SPECIFICATIONS .......................16
SPECIAL TOOLS .......................16
AXLE SHAFT SEALS
REMOVAL .............................17
INSTALLATION .........................17
PINION SEAL
REMOVAL .............................17
INSTALLATION .........................18
REAR AXLE - 226RIA
DESCRIPTION
The axle is an independent aluminum 226 RIA
(Model 44). The axle consists of a hypoid ring and
pinion, with a Hydra-Lokt differential. The differen-
tial case is supported in the housing by two bearings
located on either side of the case. The differential
cover contains two integrated frame mounting brack-
ets. The Hydra-Lokt differential has a two-piece dif-
ferential case which contains the gerotor pump
assembly and the clutch mechanism. The axle is ser-
viced as an assembly.
OPERATION
The axle receives power from the transmission
through the propeller shaft. The propeller shaft is
connected to the pinion gear which rotates the differ-
ential through the gear mesh with the ring gear
bolted to the differential case. The engine power is
transmitted to the axle shafts through the pinion
mate and side gears. The side gears are splined to
the axle shafts.
HYDRA-LOKT DIFFERENTIAL
A gerotor pump and clutch pack are used to pro-
vide the torque transfer capability. One axle shaft is
splined to the gerotor pump and one of the differen-
tial side gears, which provides the input to the pump.
As a wheel begins to lose traction, the speed differ-
ential is transmitted from one side of the differential
to the other through the side gears. The motion of
one side gear relative to the other turns the inner
rotor of the pump. Since the outer rotor of the pump
is grounded to the differential case, the inner and
outer rotors are now moving relative to each other
and therefore creates pressure in the pump. The tun-
ing of the orifices and valves inside the gerotor pump
system includes a torque-limiting pressure relief
valve to protect the clutch pack, which also facilitates
vehicle control under extreme side-to-side traction
variations. The resulting pressure is applied to the
clutch pack and the transfer of torque is completed.
Under conditions in which opposite wheels are on
surfaces with widely different friction characteristics,
Hydra-lokt delivers far more torque to the wheel on
the higher traction surface than do conventional
Trac-lokt systems. Because conventional Trac-lokt
differentials are initially pre-loaded to assure torque
transfer, normal driving (where inner and outer
wheel speeds differ during cornering, etc.) produces
torque transfer during even slight side-to-side speed
variations. Since these devices rely on friction from
this preload to transfer torque, normal use tends to
cause wear that reduces the ability of the differential
to transfer torque over time. By design, the Hydra-
lokt system is less subject to wear, remaining more
consistent over time in its ability to transfer torque.
The Hydra-lokt also benefits from using the same
lubricant supply as the ring and pinion gears.
NOTE: Differential is serviced as an axle assembly.
DIAGNOSIS AND TESTING - REAR AXLE
GEAR NOISE
Axle gear noise can be caused by insufficient lubri-
cant, incorrect backlash, incorrect pinion depth, tooth
contact, worn/damaged gears, or the carrier housing
not having the proper offset and squareness.
Gear noise usually happens at a specific speed
range. The noise can also occur during a specific type
of driving condition. These conditions are accelera-
tion, deceleration, coast, or constant load.
When road testing, first warm-up the axle fluid by
driving the vehicle at least 5 miles and then acceler-
ate the vehicle to the speed range where the noise is
the greatest. Shift out-of-gear and coast through the
ZB REAR AXLE - 226RIA 3 - 11
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