- A car's transmission has two output shafts, one extending to each front wheel. Approximately halfway along the shaft, there is a flexible, corrugated rubber boot where the shaft appears to bend. This boot houses the CV joint for that axle.
- CV joints need to be periodically lubricated; this involves removing the boots and re-greasing the exposed joints. The service interval for this maintenance varies from car to car, but it usually needs to be done only at the same time as major services (every 30,000 to 60,000 miles). You should consult your owner's manual for the recommended interval.
- The protective boots can become torn or damaged, causing dirt and dust to contaminate the CV joint and its bearings, and shortening the life of the joint. Any time you are under the car, you should check the boots for damage. Replace them immediately if they are damaged.
CV joints can also fail due to normal wear and tear, but if they are lubricated regularly, they should last several years. - The most common indicator of CV joint failure is a clicking noise and/or rhythmic vibration coming from the vicinity of the drive shaft, especially in a hard turn. There may also be a constant vibration that increases as the car's speed increases. The CV joints usually need to be replaced at that point.
- The easiest way to replace the CV joints is to remove the drive axles completely, and install new or rebuilt drive axles. The labor involved in disassembling the drive axles would negate any cost savings gained from only replacing the CV joints themselves.