CV Joint
Constant Velocity Joint — a drivetrain component that transmits power from the transmission to the wheels while allowing for suspension movement and steering.
A CV (Constant Velocity) joint is a mechanical coupling that allows a drive shaft to transmit power at a consistent speed regardless of the angle of the shaft. CV joints are essential on front-wheel-drive vehicles and all-wheel-drive systems, where the front wheels must simultaneously receive power and steer.
There are two types of CV joints on each axle shaft: the inner CV joint (closer to the transmission) and the outer CV joint (closer to the wheel). The outer joint is typically a Rzeppa-type ball joint that handles the large steering angles, while the inner joint is usually a tripod-type that accommodates the plunging motion caused by suspension travel.
Each CV joint is protected by a rubber or thermoplastic boot filled with special grease. The CV boot is the most common failure point — when it cracks, tears, or comes loose, the lubricating grease escapes and contaminants enter. A damaged boot will quickly lead to CV joint failure if not addressed. The most recognizable symptom of a failing outer CV joint is a clicking or popping noise during turns, especially at low speeds.
Replacing a CV joint typically involves removing the entire half-shaft (axle) assembly. Many mechanics recommend replacing the complete axle shaft with a remanufactured unit rather than just the joint, as the labor cost is similar and the result is more reliable.