Vibration Conditions

TYPES OF VIBRATIONS
Technically, vibration is a low-frequency trembling, shaking or grounding condition, felt or heard, that is constant or variable in level and occurs during a portion of the total operating speed range. The types of vibrations that can be felt in the vehicle can be divided into three groups:

- Vibrations of various unbalanced rotating parts of the vehicle.
- Body and frame vibrations intensified by powertrain wind or road inputs.
- Tip-in moans or resonance vibrations from stressed engine or exhaust system mounts, or driveline flexing modes.

These vehicle vibrations can also be subdivided into those that occur at low speeds and those that are most noticeable at higher speeds. Since the line between lower and higher speed vibrations is not clear, there will be vibrations that overlap the two ranges.

Typical Low-Speed Vibrations Less Than (72 kph 45 mph):
- Exhaust vibration.
- Engine harshness.
- Driveline vibration due to improper driveline angles.
- Power steering pump vibrations.
- Air conditioner compressor or drive belt vibrations.
- Take-off shudder (driveline problems).
- Brake roughness or harshness.
- Driveline roughness.
- Tire flat spots.
- Driveline slip-yoke or companion flange.
- Automatic transmission clutch slippage. Typical High-Speed

Vibrations (Above 72 kph 45 mph):
- Axle and companion flange runout.
- Driveshaft imbalance.
- Excessive tire-wheel and drum assembly imbalance.
- Tire roughness due to high non-uniformity (force
variation) or out-of-balance condition.
- Rear axle pinion gear pitch line runout.
- Excessive tire and wheel runout.
- Worn suspension components.
- Front end accessory vibrations.

Exhaust Vibration.
- Exhaust vibration is greatly reduced in exhaust systems de-coupled by a flexible coupling and mounted with blade and block hangers.