DRIVE AXLE ASSEMBLIES
A noise that is present in the differential only when
the vehicle is rounding a corner is usually caused by
LEARNING OBJECTIVES: Identify the
t r o u b l e i n t h e d i ff e r e n t i a l c a s e a s s e m b l y. T h e
components of drive axle assemblies. Identify
differential pinion gears may be too tight on their
procedures for removing, replacing, and
trunnions, or the differential side gears may be tight.
repairing drive axle assemblies.
Damaged or worn gears can produce a noise when the
The drive axle conveys the torque power from the
vehicle turns. If bearings or gears are damaged, a
differential to the wheel. It is made of steel and is solid
knocking noise can result.
in construction. Most aviation support equipment has
full-floating drive axles (fig. 2-89). The wheel fits over
The quick engine change (QEC) program will
the end of the axle housing, and the weight is carried by
guide you in the repair and replacement of
two roller bearings between the wheel and the axle
differentials. Check the latest instructions for
housing. The outer end of the axle has a flange that
guidelines and level of authorized maintenance.
bolts to the wheel. Thus, the axle goes through the axle
housing and wheel and applies turning power to the
Q2-32. What is the purpose of a differential?
outside of the wheel. The wheel is held on the axle
1. To adjust for the difference in the distance
housing by adjustment nuts (fig. 2-90). The wheel hub,
the driven wheels travel when the vehicle
roller bearings, and axle shaft are lubricated by the
turns
same gear oil that lubricates the differential. The axle
2. To adjust for the difference in torque to
can be removed by removing the flange bolts, breaking
the driven wheels
the flange seal, and pulling the axle from the housing.
3. To shorten or lengthen the propeller shaft
This can be done without removing the wheel. When
4. To connect the propeller shaft to the
replacing an axle, the proper size and thickness of the
transmission
gasket should be used as specified in the
manufacturer's instructions.
Q2-33. What is the function of the side gears in a
differential?
DIFFERENTIAL
OUTER
HOUSING
1. They connect the planetary gear and the
WHEEL
BRAKE
BEARING
DRUM
sun gear
2. They connect the shaft to the spline
AXLE HOUSING
3. They allow for one wheel to turn faster
than the other when the vehicle is turning
4. They multiply torque on both drive wheels
AXLE SHAFT
independently depending on load
WHEEL
HUB
conditions
ASf02089
INNER
WHEEL
Q2-34. Using the conventional differential, if one
BEARING
WHEEL RIM
wheel spins free from traction, it will cause
Figure 2-89.--Cross section of rear hub in full floating
which of the following effects to the other
axle.
wheel?
1.
Applies all the power to it
2.
Causes it to lose power
3.
Spins free from traction
4.
Rotate at the same speed
Q2-35. The no-spin differential uses what type of
component to prevent the loss of traction?
1.
Overrunning clutches
2.
Spline gears
ASf02090
3.
Pinion gears
Figure 2-90.--Bearing mounting and adjustment nuts of full
4.
Toothed clutches
floating construction.
2-75
