A vehicle does not get far, or anywhere, if it has a damaged drive axle. Axles are rods or shafts that connect to the drive wheels. The main purpose of axles is to transfer power from the transmission to the wheels. As the axle turns, the wheels go around, and without a functioning axle, wheels do not move.
Axles also serve to bear the weight of the vehicle and its passengers and cargo. Even though axles are built to be tough, an overloaded vehicle can sometimes crack or break an axle. Bad carrier bearings or bad potholes are other common causes of axle problems.
There are four ways to tell if your car’s axles need repair. It is time to for professionals to check your vehicle if you encounter one of the following indicators of axle damage.
1. Bad Vibes
Bad vehicle vibrations after a collision with a bad pothole, unexpected curb, or other object may indicate axle damage. Vibrations may be accompanied by an unusual rumbling noise underneath the vehicle, strange tire wobbling, or sluggish driving and steering, which may indicate a bent axle. Vibrations may be particularly noticeable during accelerations, decelerations, or turns. If the vibrations are also apparent while driving at slow speeds, that is often a good indication that there is something wrong with an axle. Excessive or unusual vibrations can cause other issues with vehicle handling, comfort, and safety. If the axle is damaged enough to cause vibrations, it generally needs to be replaced.
2. A Loud Clanking, Clunking, or Clicking
If there is an unusually load clanking or clunking as you put your vehicle into gear, or if a vehicle seems to struggle to get power as it starts to move, there may be axle-joint damage. This kind of noise usually indicates that the transmission is unable to transfer power adequately to the wheels due to slack in the joints. A loud clanking or clunking noise can also be indicative of a transmission failure, and a professional assessment may be needed.
When constant velocity axles fail, you may also hear an unusual clicking sound may when turning the vehicle as joints become loose. These clicks are on the side of the faulty axle shaft and typically become noisier during sharp or fast turns.
3. Leaking Grease
Leaking grease underneath the vehicle or on the inside tire edge can mean a leaking axle boot or CV boot, which is the rubber cover over the drive axle joint or CV joint. Though a leaking axle boot does not mean that the axle has been damaged yet, inadequate grease due to the leak can cause future problems. Dirt can also enter a joint through a broken joint cover and cause failure to the axle joint and/or axle. Axle boots and boot clamps should be inspected regularly for splits or leaks, and they are easily visible underneath a vehicle. A leaking axle boot should be repaired promptly to avoid a more serious failure to the axle system.
4. Going Nowhere Fast
If a vehicle goes nowhere, even though it starts fine, goes into gear, and has a normal engine sound, it likely has a broken axle at the universal joint. In this case, no matter how much you press the accelerator pedal, the engine only revs, and the vehicle does not move. This is the classic situation of going nowhere fast, and the vehicle will not move until it is repaired.
It is important to be aware of the critical function of drive axles and have them inspected regularly during vehicle maintenance. Though perhaps not as commonly understood, axles are as important to a properly functioning vehicle and vehicle safety as the engine, steering system, brakes, and tires are. If an axle does get damaged, have a reputable technician repair it promptly.