A constant velocity joint is a mechanical coupling that helps keep your vehicle's wheels in place no matter the angle of the joint. It is used in front-wheeled vehicles and 4WDs. It helps to keep the wheels from shocks and friction. Every CV axle has inner and outer joints. The inner CV joint connects the half shaft to the transmission unit, while the outer CV joint connects the half shaft to your vehicle's wheels. It ensures the transmission of torque to the wheels. An automobile's CV joints can degrade with time due to wear and tear. A damaged CV boot can also cause untimely damage to the CV joint by leaking away the grease meant to lubricate the joint.