Constant velocity joints, or BMW CV Joint , have a name that speaks for itself. These ingenious little joints are descendents of the common universal joint that was so common on cars up until the 1980s. But CV joints, like your BMW CV joints, have a much smoother action throughout a wide range of motion than universal joints. They both do the same thing: transfer power while flexing. But, as the name implies, CV joints can transfer motion at a constant velocity, versus the wobbling motion a universal joint takes on in certain situations.

The BMW CV joint is generally found along the rear axles, where you'll have two on each side. You can't see them--CV joints are always hidden beneath black rubber boots that look like cylindrical accordion bellows. Those boots keep the CV joint permanently lubricated, and if the integrity of the boots is maintained, you'll never have to worry about your CV joints. If you get a clicking or grinding sound at the rear wheel, though, and find a cracked CV joint boot, the jig is up. You'll need a new BMW CV joint to get things back on track.