| Table 1: | Vibration Symptoms That Are Felt |
| Table 2: | Vibration Symptoms That Are Heard |
Important: Perform the following steps in sequence BEFORE using these symptom tables.
- Begin the diagnosis of a vibration concern by reviewing Diagnostic Starting Point - Vibration Diagnosis and Correction to become familiar with the diagnostic process used to properly diagnose vibration concerns.
- Perform the Vibration Analysis - Road Testing table before using these symptom tables in order to duplicate and effectively diagnose the customer's concern.
Symptom Tables
Refer to a Vibration Analysis table as indicated in the following symptom tables, based on the most dominant characteristic of the customer's vibration concern, felt or heard, that is evident during the appropriate condition of the occurrence.
Category | Description | Typical Frequency Range | Condition of Occurrence | Area of Focus |
|---|---|---|---|---|
Shake | Can sometimes be seen or felt in the steering wheel, seat or console. Related terminology: shimmy, wobble, waddle, shudder, hop | 5-20 Hz | Vehicle Speed Sensitive Still occurs during coast down in NEUTRAL | |
Vehicle Speed Sensitive Affected by torque/load | ||||
Vehicle Speed Sensitive Affected by steering input | ||||
Engine Speed Sensitive | ||||
Roughness | Similar to the feeling of holding a jigsaw. | 20-50 Hz | Vehicle Speed Sensitive Still occurs during coast down in NEUTRAL | |
Vehicle Speed Sensitive Affected by torque/load | ||||
Vehicle Speed Sensitive Affected by steering input | ||||
Engine Speed Sensitive | ||||
Buzz | Similar to the feeling of holding an electric razor. May be felt in the hands through the steering wheel, in the feet through the floor, or in the seat of the pants. | 50-100 Hz | Vehicle Speed Sensitive Affected by torque/load | |
Vehicle Speed Sensitive Affected by steering input | ||||
Engine Speed Sensitive | ||||
Tingling | May produce a "pins and needles" sensation or may put hands or feet "to sleep". Highest vibration frequency range that can still be felt. | Greater than 100 Hz | Vehicle Speed Sensitive Affected by torque/load | |
Vehicle Speed Sensitive Affected by steering input | ||||
Engine Speed Sensitive |
Category | Description | Typical Frequency Range | Condition of Occurrence | Area of Focus | ||||
|---|---|---|---|---|---|---|---|---|
Boom | Usually heard as an interior noise similar to the noise of a bowling ball rolling down an alley, deep thunder, or a bass drum.
| 20-60 Hz | Vehicle Speed Sensitive Still occurs during coast down in NEUTRAL | |||||
Vehicle Speed Sensitive Affected by torque/load | ||||||||
Vehicle Speed Sensitive Affected by steering input | ||||||||
Moan or Drone | Similar to the sound of a bumblebee or blowing air across the top of a bottle.
| 60-120 Hz | Vehicle Speed Sensitive Affected by torque/load | |||||
Vehicle Speed Sensitive Affected by steering input | ||||||||
Engine Speed Sensitive | ||||||||
Howl | Similar to the sound of the wind howling. | 120-300 Hz | Vehicle Speed Sensitive Affected by torque/load | |||||
Vehicle Speed Sensitive Affected by steering input | ||||||||
Engine Speed Sensitive | ||||||||
Whine | Similar to the sound of mosquitoes, turbine engines, or vacuum cleaners. | 300-500 Hz | Vehicle Speed Sensitive Affected by torque/load | Go to in Manual Transmission or Diagnostic Starting Point - Automatic Transmission in Automatic Transmission - Allison |
