Abnormal Noise and Vibration While Driving - kw accessory aftermarket axle buzz case growl groan howl moan prop rattle resonance shaft transmission whine body boom part modification no OEM #PIP3140 - (Nov 24, 2004)

Abnormal Noise and Vibration While Driving

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Condition/Concern:

Some customers may notice a noise or a vibration in their vehicle that seems to be abnormal and may not have been there when the vehicle was new. Comparison of the customer vehicle noise and/or vibration levels with another vehicle of the same make and model may reveal that the customer's vehicle may have a higher level of noise and/or vibration.

Recommendation/Instructions:

The first step in diagnosis of a concern of this nature is to evaluate the customer vehicle for any aftermarket accessories. The mounting or location of some of these items are designed for convenience and many times do not take into consideration the negative effects they may have with air flow over and around the vehicle and also noise transfer paths when the item is located between two isolated components. For example the popular "step bars/nerf bars" that contact both the frame of the truck and the cab without any type of insulation are a noise transfer path of a normally operating drivetrain into the passenger area of the vehicle. Some other known contributors to noise and vibrations are running boards, bug shields, sun visors, emergency lights, ect... Removal of these items, while many times not popular with the customer, is necessary in order to evaluate whether they contribute to the customer's concern.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

Models:

(2005 and Prior Passenger Cars and Light Duty Trucks)

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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