What are CV Joints
Constant-velocity joints allow a rotating shaft to transmit power through a variable angle, at constant rotational speed, without an appreciable increase in friction or play. They are mainly used in front wheel drive and all wheel drive cars. Rear wheel drive cars with independent rear suspension typically use CV joints at the ends of the rear axle halfshafts, and increasingly use them on the propshafts. Audi Quattros use them for all four half-axles and on the front-to-rear driveshaft (propeller shaft) as well, for a total of ten CV joints.