A CV axle s the most important part of your driveline that you've never heard of. We'll tell you what it is, how it works, and how to tell if it's going bad.

When that happens, the whole axle may need to be replaced. CV axle boots often last the life of a vehicle and are not listed among items that need periodic replacement as part of vehicle maintenance.

As recently as 10 years ago, the repair meant removing the pertinent axle and taking out the failed CV. You'd then replace it and the boot, lubricate the new and old joint with fresh grease ...

A drive axle boot is supposed to protect the CV joint from becoming dirty or filled with debris. Because this joint is also greased, faulty CV boots could cause the filth to build up in your vehicle ...

My older Lincoln Navigator's CV boot is leaking grease. I took it to two different shops and they both want to replace the axle, not the boot.