Whats a CV Joint and its job in the car?

Question

I had mine changed in my suv.

Reason is that it has a pop sound while making tight turns.

Answer 1

a cv shaft is your axles. each axle consists of an axle shaft, an inner cv joint and boot, and an outer cv joint and boot. the purpose of the boots is to hold the grease in and keep the joints lubricated. when the boot develops a tear, the tear gets worse and worse, grease gets thrown out of the joint and boot, it loses lubrication and the joint cracks. that was your popping noise when you turn.

Answer 2

It's a flexable joint on the front axle which allows you to turn the wheels while driving.  And that's exactly the sound it will make when it's going bad.