The Colorado statesman., 1921-11-12
NOISY GEARS
mean DANGER
Tell Story Owner Ought to Inter
pret in Terms of Dollars
and Cents.
LACK OF OIL CAUSES TROUBLE
Study Of Rear Axle Construction and
Of Transmission Would Save Owner
Much Trouble and Some
Money.

II Is fact that great number of
our cars are being driven over the
roads with noisy gears. This Is being
done either through Ignorance or In
direct defiance of that well established
rule "a stitch In time, etc" The noise
lf the gear besides being unpleasant,
teiIs n story which the owner ought to
Interpret In terms of dollars and cents.
without knowing anything at all about
rear axle or transmission, the
average man should be able TO know
the difference between rear axle that
is normal and one that is not. He may
aot know the exact cause of the
trouble or the manner in which 1t may
he remedied. but he certainly ought to
be able to determine If II needs the
attention of a mechanic. The reason
for this Immediate Interpretation is
TO save the owner money. for, like n
case of pneumonia developed from n
mere cold, If attention were given
early enough. the serious allment would
not have developed. SO with gears.
Once their bearings begin to wear and
so throw the gears out of their relative
running truth. the gears themselves
are affected so that II the condition is
allowed TO get worse, pretty soon the
gears cut and chip and then fail alto
gether.
TWO Out Of Five Noisy.
Observations were made at one spot
along frequented highway. where for
hours an average of 1000 cars per
hour passed. A fairly accurate check
was kept on gear noises on level
stretch and without eXaggerating,
every two cars In five had noisy rear
sxIes 1t Is doubtful II the owners of
che cars realize the meaning of such
noises, and If they know that In 80
per cent of the cases the condition
can be corrected for few dollars, per-
haps requiring only bearing adjust
ment, shifting of the difterential, a
quart or so of oil.
The rear axle Is not the only offender,
The transmission gears need the
same protection. but usually they are
not at fault
In order to understand just how
noisy gears come into being, one
should study the rear axle construc-
ton. The driving pinion at the end Of
the propeller shaft is mounted usually
on two bearings. This pinion meshes
with the large or ring gear of the diff
ferential unit, the unit Itself being
mounted on two bearings which rest
ia the differential housing. In order
that the ring gear and the plnion do
their work without noise the teeth OF
these gears must mesh properly. If
the correctness of the mesh is de-
stroyed then noise results. Should the
pinion shaft (hence the piniOn itself)
move relative to the ring gear the
tooth contact is at once changed and
YOU get noise. The noise is not nee
essariiy steady one, but 1t may be
interrupted, due to the fact that the
new areas of contact of the teeth are
not all alike. There may be high
spot on one or two or more teeth and
when these high spots are struck the
noise changes.
Lack of fabrication.
The plnion bearings may be of the
bali or roller type and there Is. In
most cars. means of adjustment of
the bearings after they have been
worn slightly. The cause of the wear
may be natural. but in nine out of ten
cases It is due to lack of fabrication.
The differential bearings are not un-
like the pinion bearings in the effect
they have no gear noises. These bear
ings IL worn even slightly will allow the
whole differential unit to shift side
ways and so disturb proper gear mesh.
Once they start to wear and permit
this action, the wear is rapidly accel-
Grated so that I'm very short time
there is no definite tooth contact.
The time to stop the gear noises is
Immediately they appear. 1t Is
cheaper for you and better for the car.