MOTOR TRUCK SERVICE MANUAL
Fig. 16-Twisted Shaft
Fig. 16 illustrates a portion of a twisted axle shaft caused
by abusive or very severe operation.
Such parts condition is produced by severe operations
frequently in combination with abusive handling of
This is a preliminary failure stage where the shaft has
Usually investigation will disclose the
twisted and alignment was destroyed, but no signs of
vehicles are overloaded or the drivers are improperly
fracture are in evidence. The shaft has passed its period
using the equipment.
of usefulness and should be replaced. If it is not, it will
continue to twist until an ultimate fracture will occur.
Technically the damage is the result of a series of torque
With complete failure, other axle parts may be damaged
or stress applications greater than the strength of the
with consequent substantial increase in repairs cost.
metal. Most always these are in both directions and
The lubricant should be changed and the axle well
applied thru low and reverse transmission gears. A
cleaned after such shaft breakage to eliminate all
twisted shaft that has fractured is sometimes thought, by
possibility that pieces might remain in the unit to cause
persons not experienced in metal fractures, to be
later damage. The shaft on the opposite side of the
evidence of seams in the steel It is not, for the small
truck should be very carefully examined.
noticeable cracks are caused by fatigue.