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Sec. 21
Page 208
GM COACH MAINTENANCE MANUAL
TROUBLE SHOOTING
2, Loose
spring
clip
nuts,
If
axle
is
shifted
on
springs,
relocate and tighten spring clip
nuts,
Symptoms
indicating trouble
in
transmission
is
sometimes
caused by another assembly, such
as axle, propeller shaft, universal
joint, or clutch. Therefore, before
removing
the
transmission
to
locate the trouble, always check
the possibility that trouble may
exist in other units.
NOISY
Before
beginning
the actual
operations
to
eliminate
noise
attributed to transmission, make
sure that the noise is not coming
from another unit in vehicle, such
as propeller shafts or rear axle,
Also bear in mind that a limited
amount of the transmission gear
"noise" is normal, except when
unit is in direct drive.
Following
are some of the causes of noise.
1.
Worn
or damaged parts.
2, Improper
or
insufficient
lubricant.
SPRING LEAF FAILURE
l,
Overloading
driving at excessive
rough terrain.
TRANSMISSION
vehicle
or
speed over
TROUBLE
3. Tr,msmission
and
clutch
housing out of alignment. Tighten
transmission
mounting
bolts
if
not tight, otherwise determine and
correct
cause of misalignment,
SHIFTING DIFFICULTIES
l. 1mproper
adjustment
of
clutch release linkage.
2.
Binding
in
transmission
control cover.
3, Bent or binding of control
rods
at guides.
4. Wrong
driving practices.
5, Too heavy gear lubricant,
6.
Reverse
solenoid linkage
out of adjustment will contribute
to
difficulty
when
shifting into
reverse,
JUMPING OUT OF GEAR
1, Improper shifting of gears.
Completely engage mating gears
before
releasing
clutch,
Move
gearshift lever until poppet en-
gages notch in shift rod,
2. Loose rebound clips.
3, Shackle and bracket pins
frozen due to lack of lubrication.
4. Grabbing brake.
SHOOTING
2, Excessive end play due to
wear in one or more of following
parts: Shift fa.rks, fork grooves in
sliding clutches, thrust washers,
mainshaft, countershaft, or gear
bearings or bushings.
3, Broken
snap
rings
per-
mitting gears or shafts to move
endwise,
4, Shift forks
bent or loose
on shift rods,
5,
Loose propeller shaft com-
panion flange nut.
6.
Poppet
springs
weak
or
broken,
LUBRICANT LEAKS
1. Lubricant level too high,
2, Worn oil seal,
3, Main drive gear bearing
retaining screws loose,
4. Cover plate screws loose
or
gaskets defective,
5, Bearing
retainers
loose,
6.
Transmission case cracked
or broken,
PROPELLER
SHAFT
TROUBLE
SHOOTING
EXCESSIVE NOISE
OR VIBRATION
1. Universal
joints in need
of lubrication,
2,
If
propeller shafts are not
assembled with universal joints
in the same plane, vibration will
result,
Check for this condition
and if found, disconnect propeller
shafts and place universal joints
in same plane,
3, Worn universal joint bear-
ings or journals, or sprung prop-
eller shaft will cause vibration
and noise.
4,
Any mechanical movement
has vibration periods, which do
not
result
in
noise
until
they
tune
in
with
some
other
part
or unit. In this connection, loose
or broken body panels, etc.,should
be checked as the source of noise
if
the
above
remedies
do
not
correct the condition,
WHEELS,
HUBS,
AND
TIRES
TROUBLE
SHOOTING
W .llen localizing wheel and tire
trouble symptoms, also consider
vario-us related systems such as
wheel
alignment,
steering gear
and brake system,
Deficiencies
in
these systems or unii:s will
affect
performance
of
wheels,
tires, and hub bearings.
EXCESSIVE OR UNEVEN
TIRE WEAR
1, Unequal pressure in tires,
2, Front wheel misalignment,
3, Bent
wheels or damaged
wheel bearings.
4, Broken,
bent,
or
worn
front axle parts.
WHEELS POUNDING
Hub bearings damaged or in
need of adjustment. A bent wheel
will also cause this condition.
SHIMMY
Conditions which cause wheel
shimmy are listed under "Front
End Trouble Shooting.''
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