Noise, Vibration and Harshness
Noise, Vibration and Harshness (NVH)
Noise Conditions
- Gear noise is typically a howling or whining due
to gear damage or incorrect bearing preload. It
can occur at various speeds and driving
conditions, or it can be continuous
- Chuckle is a particular rattling noise that sounds
like a stick against the spokes of a spinning
bicycle wheel. It occurs while decelerating from
64 km/h (40 mph) and can usually be heard all
the way to a stop. The frequency varies with
vehicle speed.
- Knock is very similar to chuckle, though it may
be louder and occurs on acceleration or
deceleration. The teardown will disclose what
has to be corrected.
Clicking, popping or grinding noises may be caused
by the following:
- worn, damaged or incorrectly installed wheel
bearing, suspension or brake component.
Check and rule out tires, exhaust and trim items
before disassembling the transmission to diagnose
and correct gear noise.
The noises described under Road Test usually
have specific causes that can be diagnosed by
observation as the unit is disassembled. The initial
clues are the type of noise heard on the road test
and driving conditions.
Vibration Conditions
Vibration at highway speeds may be caused by
the following:
- out-of-balance front or rear wheels.
- out-of-round tires.
Shudder or vibration during acceleration may be
caused by the following:
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Noise, Vibration and Harshness (NVH)