Road Test

DESCRIPTION
A vibration diagnostic procedure always begins with a road test. The road test and customer interview (if available) will provide much of the information needed to find the source of a vibration. During the road test, drive the vehicle on a road that is smooth and free of undulations. If vibration is apparent note and record the following:
^ The speed at which the vibration occurs.
^ What type of vibration occurs in each speed range-mechanical or audible.
^ How the vibration is affected by changes in vehicle speed engine speed and engine torque.
^ Type of vibration sensitivity-torque sensitive, vehicle speed sensitive or engine speed sensitive.
Use the following explanation of terms to help isolate the source of the vibration.

TORQUE SENSITIVE
This means the condition can be improved or worsened by accelerating, decelerating, coasting or maintaining a steady vehicle speed and application of engine torque.

VEHICLE SPEED SENSITIVE
This means the vibration always occurs at the same vehicle speed and is not affected by engine torque, engine speed or transaxle range.

ENGINE SPEED SENSITIVE
This means the vibration occurs at varying vehicle speeds when a different transmission range is selected. It can sometimes be isolated by increasing or decreasing engine speed with the transaxle in NEUTRAL, or by stall testing with the transaxle in gear. If the condition is engine speed sensitive, the condition is not related to tires.

TIRE NOISE
If the road test indicates there is tire whine, but no shake or vibration, the noise originates with the contact between the tire and the road surface.