CV Joints Boots U-Joints

Constant VelocityPalmer's Auto Repair (CV) and Universal (U) joint imagesConstant velocity (CV) axles and drive shafts play a large role in getting your car or truck down to road.  They connect the transmission output shaft to the wheels. 

CV axles connect your transmission to the steerable wheels of your car and allow the wheels to turn back and forth without kinking, binding, or otherwise interfering with control of your car.  Because CV axles must be able to flex, and turn, at the same time, they utilize these special joints. CV axles on front and all-wheel-drive cars also use a rubber boot to encase the CV-joint.  The boot will wear out over time.  When the boot splits  the CV joint dries out (looses it's grease) and gets dirty. The joint wears out and begins to separate.  The wear is permanent in this case and the whole CV axle must be replaced. 

A drive shaft universal joint (U-joint) behaves like a CV axle in that it allows the drive shaft to move up and down with binding.  The difference is that a CV axle is one unit and the CV joint can't be replaced as separate from the axle.  But a u-joint is a serviceable part and can be removed from the drive shaft and replaced.  Drive shaft u-joints are very different from CV axles in that they are essentially comprised of four needle-bearing sets that are permanently greased.  Because of these physical differences, the cost of replacing a u-joint is generally a lot less than replacing a CV axle.

Signs of worn CV axles and u-joints are when you hear a clicking sound while going around corners, or a cluck sound when leaving a full stop.  If you are hearing these tell-tale signs, give us a call to schedule and inspection or a test-drive with one of our technicians.