A constant velocity (CV) joint allows a drive shaft to transmit power at varying angles without too much friction or play. Many cars have CV joints in their suspensions. In front-wheel-drive cars, the CV joints either connect the transmission to the drive shafts or the wheels to the drive shafts. CV joints are great, but they do break down
Humming noises from the CV joints can mean a variety of problems. For example, inadequate lubrication can lead to humming noises due to the increased friction. In many cases, however, the humming noises indicate worn bearing or damaged bearings.
CV joints are critical in helping the wheels turn whenever the car changes direction. As a result, the joints experience enormous pressure when turning. Thus, bad CV joints usually trigger loud noises whenever the vehicle is turning, especially at high speeds.
Some of the noises that come from the CV joints are due to acceleration also increase the forces in the CV joints. If the CV components are worn out, they will experience more play than they normally do. Changing the rotational speed at the joint, by accelerating or decelerating the car, will generate some noises from the joint.
Shudders or Vibrations
It's not just noises that might signal CV joint problems, vibrations or shudders can also point to the same problem. The same problems that cause the noises described above, such as worn bearings, can also trigger the vibrations and shudders. This also means the vibrations might increase when accelerating or cornering.
The CV joint is encased in a flexible rubber known as the CV boot. The boot keeps foreign substances, such as water and dust, out of the joint. The boot is greased in the inside to reduce friction and encourage free movements within the joint. The grease might leak out of the boot if the CV joint is damaged and the boot is torn. If that is the case, you might notice signs of leaking grease on the inner edge of the tire next to the joint or on the underside of the car.
Lastly, even the car's ride comfort will be affected if the CV joint is damaged. The increased play between the components of the CV joint will make the car bounce up and down even on flat surfaces.
Get an auto mechanic to diagnose your car's CV joint if you notice any of the above symptoms. You will need to have the joint replaced if the diagnosis confirms a bad joint. For more information, visit a car repair service.