Road Test Quick Checks

1. 24-80 km/h (15-50 mph): With light acceleration, a moaning noise is heard, and possibly a vibration is felt in the floorpan. It is usually worse at a particular engine speed and at a particular throttle setting during acceleration at that speed. It may also produce a moaning sound, depending on what component is causing it.

   Refer to Tip-In Moan Diagnosis charts.

2. 40-72 km/h (25-45 mph): With steady to heavy acceleration or deceleration, a rumble-type noise is heard. It is very intense during heavy acceleration or deceleration and very light during cruise or neutral coast. The vibration is hard to duplicate with vehicle supported on a hoist, since wheels are coasting free.

   Refer to Driveline Vibration Diagnosis.

3. High Speed: With slow acceleration and deceleration or at constant speed, a shake is sometimes noticed in the steering wheel/column, seats, floorpan, trim panels, or front end sheet metal. It is a low frequency vibration (around 9-15 cycles per second). It may or may not be increased by applying brakes lightly.

   Refer to High Speed Shake Diagnosis charts.

4. High Speed: A vibration is felt in the floorpan or seats, with no visible shake, but with an accompanying sound or rumble, buzz, hum, drone, or booming noise.

   It will exist in all drive modes, but may vary somewhat in acceleration, deceleration, float, or coast modes. In some cases the driveline vibration is eliminated in the float mode.

   Refer to Driveline Vibration Diagnosis charts or Driveline Balance Diagnosis charts.

5. 0-High Speed: A vibration is felt whenever the engine reaches a particular rpm. The vibration can be duplicated by operating the engine at the problem rpm while the vehicle is sitting still. It can be caused by any component from the fan back to the clutch or torque converter and by anything that turns at engine speed when the vehicle is stopped.

   Refer to Engine Accessory Diagnosis charts.