CV Axle
Constant Velocity axle—a drive axle assembly containing CV joints that transfers rotational power from the transmission to the wheels at a constant speed, allowing for steering and suspension movement.
A CV axle (or half-shaft) is a rotating axle shaft used primarily in front-wheel-drive (FWD), all-wheel-drive (AWD), and independent rear suspension vehicles. It features an inner CV joint connected to the transmission or differential and an outer CV joint connected to the wheel hub.
These specialized joints are wrapped in protective rubber boots packed with grease, allowing the axle to transmit torque smoothly at varying angles as the wheel moves up and down with the suspension and turns for steering. If the protective boot tears, the grease leaks out, and dirt and water enter, rapidly destroying the joint bearings.
The most common sign of a failing CV joint is a loud clicking or popping noise when making sharp turns, along with grease splattered inside the wheel well. Replacing a torn boot early can save the axle, but once the joint is noisy, the entire CV axle assembly must be replaced.