The most common reason a CV axle can be replaced is when a boot splits causing the grease to leak out.

A CV joint won’t last long, without adequate lubrication. Certain reasons for replacing a CV axle include excessive wear or damage caused by an accident, or excessive rust. If a bad CV axle is not replaced in time, it may break or jam when driving leading to a danger to safety.

One of the CV axles is longer in cars and SUVs with a transversely mounted engine (typically the right side), and has a hanger bearing. Where a hanger bearing is worn out or disruptive and can not be replaced separately, the entire CV axle is replaced as well.

What are the signs of an axle with low CV? A clicking noise while turning in turns is one of the common symptoms of a bad exterior joint. An overly worn CV axle will produce a clunking or clicking noise when moving from decelerating to accelerating.

Many FWD, AWD, and 4WD vehicles have CV axles.
It can cause the vehicle to rock laterally (side-to-side) at acceleration if an inner joint is worn out or sticked. A bad CV axle may in some cases cause a vibration.