For 1990-2009 cars

# Abnormal Noise And Or Vibration While Driving - keywords accessory aftermarket axle body boom buzz case grown growl howl moan modification no OEM part prop rattle resonance shaft transmission whine

Subject: | Abnormal Noise and Or Vibration While Driving

Models: | 2008 and Prior Passenger Cars and Light Duty Trucks including Saab and Saturn

This PI was superseded to update Model Years. Please discard PIP3140A.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this 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, vent shades, emergency lights, custom grilles, ski racks, bicycle racks, etc... 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 diagnostic or repair 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.