A damaged axle isn't something you can ignore, as it will at first make a car difficult to drive and will later leave it broken down on the side of the road. The axle is what connects your tires to the drive train, by way of the CV joint. Know the signs of axle trouble so you can schedule a prompt repair.
1. Wheel Vibration
Your wheel should not vibrate when you are driving. If it does, then there may be issues with your axle. This is especially true if the vibrations are severe enough that others in the car can feel them, or if the vibration tends to become worse upon a turn. Axle vibrations are typically more severe at low speeds but can be present at high speeds as well. There are a few other issues, mainly with the tires, that can lead to vibration, so a shop needs to check it out.
2. Grease Stains
When the CV joint on the axle begins to crack and degrade, the lubricating grease within it begins to leak. You may find greasy stains on the driveway where you park, for example. It's also common for grease to splatter onto the tires and inside of the fender when driving, as well as coat the CV joint and axle itself.
3. Knocking Turns
Do you hear a clicking or knocking noise only when turning the vehicle? If so, then this is an early sign of a failing axle. Over time, the sound will get worse, usually to the point where you may hear it even if you aren't turning the wheel. All odd noises should be checked out by a mechanic, especially noises that tend to only occur during a turn.
4. Clicking Acceleration
Clicking noises may also occur when driving straight, particularly when you are slowly accelerating. Once you reach a cruising speed, the noise may stop, especially if the axle is to blame. The noise is usually loud enough to be heard inside the car, but in some cases, you may only be able to hear it with the windows down.
5. Poor Braking
As the axles give out, the wheels on your car will come out of alignment. One side effect of this is that the brake pads may not align properly anymore. You may have difficulty braking or there may be grinding noises when you put pressure on the brake. Your repair tech will check both the brakes and the axles for damage.
Contact an automotive repair service if you suspect an issue with your car's axle.