Arizona republican., 1919-10-19

Should one gear run out of true, that
is, wabble even the slightest bit, the
tooth pressure will be greater ana
there. will be more noise. The inter
mittent howl you hear from an axle
or transmission Is due to the alterna-
ton of this high stress. One second 1t
is relieved, the next it is severe again. |
Every time the gear wabbles you
might say there is q pinching of teeth |
they press too much against each |
other.
In the transmission there are two |
or three or more shafts mounted on
bearings in the housing. These shafts
carry gears. some of which slide on a
shaft, When the transmission is new
these shafts and gears are so fitted
that the gears will run in one true
circle all the time. ANY change in the
position of the shaft or any change in
the gear or its teeth will upset the true
running of the gear, and the result will
be more noise. On all speeds but high
you hear more noise as result of the
higher tooth pressure, but that noise or
hum in well fitted gears and well
mounted shafts is a steady noise Tor
any given speed. In abnormal opera
| ton there may be a rafting sound as
| though something were loose in the
Transmission or the sound instead of
being a steady hum is a series of
bowls varying with intensity while the
car moves along at the same speed
| These noises may be caused by lack
of proper fabrication, badly worn
teeth, gears shifted slightly out of true
positions Cooked over trifle), high
/ spots on the gears caused by a soft
tooth which was worn down quickly or
by foreign matter getting between the
teeth; worn shaft bearings bent
shafts, Clipped gear teeth.
| A transmission may operate for
thousands of miles with any Of the
above, but it always is cheaper to at
tend to any serious matter at the be-
ginning. For example, shaft bearings
when worn badly allow the whole shaft
to sway, throwing all the gears on that
and the adjacent shafts out of proper
/ flesh. The result is that the gears wear
unevenly. The condition existing for
some time may call for practically a
new transmission. Especially where
bearings are adjusted should advan-
tage be taken of the feature and the
shafts be kept in proper alignment
i Rear axles of today are none too
good as whole, but they would give
far better and longer service If the
driving were properly done. Quick en-
lgagement of the clutch, heavy over
loads, even though for an instant,
harsh application of brakes on rough
roads, lack of fabrication are some Of
the causes of worn pinion and differ
entail bearings and worn gears. The
average car has an adjustable driving
pinion and differential unit. When
new these bevel gears operate so that
the gears mesh in one certain way. II
bearing wears and allows the pinion
to change its mesh, or If the differen.
tial bearings wear and allow the whole
unit to shift over away from or toward
the pinin, there is bound to be noise
produced and noise OF an unpleasant
character. The bearings. If they are OF
the ball type with ball separators OF
cages, may show breaking down oil
the cage. Pieces of the cage fall be-
: tween the gear teeth, chipping them
and causing more noise. The bearings
themselves then allow more freedom
of movement of the differential OF
pinion. 1t is absolutely necessary that
the two gears retain fixed position
and as soon as there is an unusual
gear noise from the axle the drive,
can say with certainty that the gear
are not running so or that there IL
solid matter between the teeth.
Where the pinion is keyed to the enc
of Nthe propeller shaft there often /.
wear in the key and keyway. Thi.
will allow the pinion rotational free
dom and will be heard in the form Of
loud click on starting the car OF
stopping. Usually when pulling thi,
play will not be heard.