Symptoms of a Bad Automotive Drivetrain CV (Constant Velocity) Axle

Introduction

CV axles different than a normal straight axle, and with that come different symptoms when the CV axle is having an issue. These axles allow the movement of suspension and steering parts while delivering engine power to the wheels. CV axle's are designed with a circular rubber boot that is responsible for holding the lubricating grease inside the CV joint.

What Goes Wrong?

Most of the time when a CV axles goes bad it will do so in one of two ways, the CV joint will wear out and make noise/vibration, or the CV axle shaft will break and stop the vehicle from moving. Though there is not much that can be done to prevent the shaft breakage inspection can help prevent a failure. The CV joint is protected by a grease retaining rubber boot, this boot should be inspected to ensure there is no leakage. Look for grease splattered around the wheel well or under the vehicle. If you see any signs of grease as in the image below the CV axle should be replaced.

Common Symptoms of a Bad CV Axle

1. By far the most popular sign the CV axle is going out, is in a sharp turn at slow speeds, the instant you accelerate in the turn you will hear a popping or clicking noise. This means the CV axle is worn out, if you are turning left and you hear the noise, the left hand CV axle is worn out, and visa versa.
    
2. Under acceleration a worn out CV axle will cause vibrations at higher speeds of 35 to 55 MPH under power only, when you let off of the accelerator the vibration stops. This is because the balls in the CV joint have worn into the outer cup hindering the smooth radial movement of the joint.
    
3. If a CV axle breaks completely, the car will be rendered non operational. This is because the opposing axle will not be able to move the car due to the differential spider gears which will spin internally, not delivering the engine's power to the remaining axle.

Credits

This guide knowledge base was created by the 2CarPros Team, and by Ken Lavacot: Automobile repair shop owner and certified master automobile technician of over 30 years. If you have question or need help please ask one of our experts we are happy to help. Please visit our 2CarPros YouTube Channel.