Edward's Transmissions+ Auto Systems Expert - Michigan Road

Tech Tip Tuesday: U-Joints and CV Joints

Universal joints and constant velocity joints both have one job. They let a driveshaft or axle shaft transmit rotational power through an angle, as the suspension moves up and down.

U-joints are found in rear-wheel drive and four-wheel drive vehicles, typically at each end of the driveshaft. They use a simple cross-shaped design with four bearing cups. CV joints are found in front-wheel drive vehicles and on independent rear suspensions, using internal ball bearings to transmit power more smoothly at steeper angles.

A bad u-joint produces a clunk when shifting between drive and reverse, a vibration that increases with speed, and sometimes a squeak that changes with vehicle speed. A bad CV joint produces a clicking or popping sound during turns, especially under acceleration, and in later stages a grinding sensation that transfers through the steering.

Either failure, left unaddressed, progresses to a roadside breakdown.