In order to perform an accurate road test, it is important that certain checks be performed to eliminate other possible problems that may point to the front axle. Make sure to check the following items before performing a road test.

1. Inspect the tires for correct inflation pressure. Refer to Tire Placard on the drivers door pillar.
2. Inspect the front axle housing for correct oil level. Refer to Lubricant Level Check Checking Front Axle Oil Level.
3. Inspect the transfer case for correct oil level. Refer to Lubricant Change Checking Transfer Case Oil Replacement in Transfer Case.
4. Inspect the wheel nuts for correct torque specification. Refer to Fastener Tightening Specifications in Tires and Wheels.
5. Inspect the undercarriage for loose attaching front axle parts which may cause noise.
6. Inspect the front suspension for any loose or worn components. Refer to Suspension Component Inspection in Front Suspension.

When road testing a vehicle, a smooth asphalt road surface is preferable because it dampens a high degree of road noise. Road test the vehicle to verify the problem and the speed and/or rpm at which it occurs. Once the problem has been verified, duplicate the noise under varying road conditions to eliminate the possibility of road noise. Once the noise and the conditions under which it exists have been verified, the type of noise and its location must be identified.