Constant Velocity Joint (CV Joint)
Constant velocity joints (CV joints) are used on (FWD) front-wheel-drive, (AWD) all-wheel-drive, and some rear-wheel-drive vehicles. They transfer the torque or power from the transmission to the drive wheels. Front-wheel drive half shafts have an inner and an outer joint. The inner joint transfers power while still allowing for the suspensions up and down movement. The outer joint allows the shaft to transfer turning power at different angles.
A CV joint is lubricated with thick grease contained in a rubber boot; a torn boot results in a loss of this vital lubricant and premature joint failure. A faulty CV-Joint makes a clicking or popping noise while slowly turning corners. It's because the outer CV-Joint is working at a greater angle.