GMC CHEVROLET Silverado 6500HD 2019 Owner's Manual page 396

Drive Shafts
At the regular lubrication interval,
check universal joints, slip joints,
slip joint boot, and carrier bearings
for any evidence of wear or
looseness.
Warning
If vibrations from the drive shaft
are felt, stop the vehicle
immediately. Possible injury or
damage to the drive shaft or other
components could occur, which
could cause a crash resulting in
injury, death, or property damage.
Suspension
Caution
To prevent property damage, do
not adjust air suspension height
to any setting other than the
specified setting. Altering the
height setting will change the
(Continued)
Caution (Continued)
driveline angle and may result in
unwarrantable component
damage, such as transmission
component damage.
If equipped with the optional air
suspension for the rear axle, verify
air suspension height at engine oil
change intervals. See the
appropriate service manual.
Suspension alignment must be
maintained at all times.
See Capacities and Specifications
0 408 for proper U-bolt torque
values.
Periodically:
Check the condition of spring
leaves for evidence of fatigue,
bending, or breakage.
Check the condition of
suspension mounting brackets
and bushings.
Service and Maintenance
Ensure that suspension mounts
(such as brackets, bushings,
fasteners) are tight.
Ensure that torque rod mounting
fasteners are tight.
Check U-bolts as follows:
5.1. After the chassis has been
operating under load for
1 600 km (1,000 mi) or six
months, whichever comes
first, the U-bolt nuts must
be torqued again.
5.2. Thereafter, the U-bolt nuts
must be torqued every
58 000 km (36,000 mi).
Torque interval may be
lowered to 40 000 km
(25,000 mi) to synchronize
with oil change interval.
Front Suspension
The front suspension should be
regularly inspected for loose, worn,
or broken components. Front
suspensions/axles should be
checked periodically for proper
alignment to promote maximum
tire life.
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