How to tell if a Subaru CV axle is bad?

If you own a Subaru, it's important to be able to identify when your constant velocity (CV) axle is starting to fail. A bad CV axle can cause a range of issues, from vibrations and noises to difficulty steering and even complete axle failure. In this article, we'll provide a detailed guide on how to tell if your Subaru's CV axle is bad.

What is a CV Axle?

A CV axle, also known as a constant velocity joint, is a crucial component in your Subaru's drivetrain. It connects the wheel hub to the differential, allowing the wheels to rotate at different speeds while transmitting power from the engine to the wheels. CV axles are designed to withstand the constant flexing and twisting that occurs during normal driving conditions.

Signs of a Bad CV Axle

There are several common signs that may indicate a problem with your Subaru's CV axle:

• Clicking or popping noises: As the CV axle begins to wear, you may hear a clicking or popping sound, especially when turning or accelerating. This is often one of the first signs of a problem.


• Vibrations: A bad CV axle can cause noticeable vibrations in the steering wheel, floorboard, or entire vehicle, especially at higher speeds.


• Difficulty steering: If the CV axle is severely damaged, it can make the steering feel loose or "sloppy," making it harder to control the vehicle.


• Grease leaks: Look for signs of grease leaking from the CV axle boot, which can indicate a tear or crack in the boot.


• Uneven tire wear: A bad CV axle can cause uneven or premature tire wear, as the wheels are not able to rotate at the same speed.

If you notice any of these signs, it's important to have your Subaru inspected by a qualified mechanic as soon as possible to prevent further damage and ensure your safety on the road.

Inspecting the CV Axle

To inspect the CV axle, you'll need to visually examine the boot (the protective cover) for any cracks, tears, or signs of grease leakage. You can also try gently rocking the wheel back and forth to check for any play or looseness in the CV axle. If you notice any issues, it's best to have a professional mechanic take a closer look and determine if the CV axle needs to be replaced.

Replacing a CV axle can be a complex and time-consuming task, so it's important to address any issues with your Subaru's CV axle as soon as possible to avoid more costly repairs down the line.

How long do Subaru CV axles last?

80,000 to 100,000 miles
The lifespan of your CV axle is typically fairly long, withstanding 80,000 to 100,000 miles under regular driving conditions. If you begin hearing a loud, rhythmic clicking noise as you turn, it's a good sign the axle is failing.

How do you tell if it's a CV joint or wheel bearing?

A bad wheel bearing typically causes a humming or growling noise that gets louder with speed and can also cause steering wheel vibration and uneven tire wear. A bad CV joint is more likely to make a clicking or popping sound when turning and cause vibrations or a clunking sound during acceleration or deceleration.
 
This video explains the differences between a bad wheel bearing and a bad CV joint, including common symptoms like noises and vibrations: 44sFindTheBestCarPriceYouTube · Apr 14, 2023
Bad wheel bearing

• Noise: A constant, low-pitched humming, grinding, or growling sound that changes with speed and can often be heard when the vehicle is moving straight. 
• Vibration: A vibration in the steering wheel or chassis, especially at higher speeds. 
• Loose steering: A feeling of looseness or imprecision in the steering. 
• Uneven tire wear: The tire can wear unevenly, indicating a wobble. 
• Warning lights: The ABS or traction control light may come on. 

Bad CV joint

• Noise: A clicking or popping sound that is most noticeable when turning, especially at low speeds. 
• Vibration: A vibration or shaking feeling while accelerating or turning. 
• Clunking: A clunking sound can be heard when accelerating or decelerating. 
• Grease leakage: A sign of a bad CV joint is grease leaking from the rubber boot that protects it. 
• Car pulls to one side: The vehicle may pull to one side if the joint is severely damaged. 

How to diagnose

• Listen during turns: Turn the steering wheel sharply at a low speed. A clicking or popping sound indicates a bad outer CV joint. 
• Listen for constant noise: Drive at various speeds in a straight line. A constant humming or growling noise is more indicative of a bad wheel bearing. 
• Check for grease: Look for any signs of grease leaking from the rubber boots on the axles. 
• Feel for vibrations: Pay attention to vibrations felt through the steering wheel or the rest of the car. 

This video shows how to diagnose a bad CV joint by checking for play and noise: 36sWoody's Works GarageYouTube · Aug 26, 2024

How do I know if my Subaru CV joint is bad?

But I don't get much noise but then if I turn. It. You hear that rumble and feel that rumble that's the U-jints. Trying not to break in half. So if when you're driving straight. Ahead.

How to test if your CV axle is bad?

You can test for a bad CV axle by listening for a clicking or popping noise while turning, as well as feeling for vibrations or shaking, especially when accelerating. A visual inspection is also crucial to check for torn or cracked CV boots that may be leaking grease. 
1. Perform a road test 

• Drive slowly in an open area like a parking lot and make sharp turns in both directions. 
• Listen for a rhythmic clicking or popping sound, which is often the most telling sign of a worn outer CV joint. 
• Pay attention to any vibrations or shaking in the steering wheel, particularly when accelerating, which can indicate a worn or imbalanced axle. 

2. Conduct a visual inspection 

• Look for torn or cracked rubber CV boots, which are the protective covers for the joints. 
• Check for grease that has splattered or leaked from a torn boot onto the surrounding suspension components or the ground. 
• While a bad boot doesn't always mean a bad joint, it will allow dirt and debris in, leading to premature wear. 

3. Check for play or looseness 

• If possible and safe to do so, lift the vehicle so the wheel is off the ground.
• Grasp the CV axle and try to move it up and down, or side to side, to check for any excessive play or "slop".
• If the axle has significant movement (more than about half an inch), it indicates worn bearings.