Your vehicle’s drivetrain consists of many components that perform the critical task of moving it, as well as ensuring that it can stand up to the stresses and abuse that you put it through. Moving a vehicle on a tarmac road under shifting speeds, acceleration, braking, cornering, gradients, uneven roads, and varying load conditions is harsh enough. Now throw in some off-road action featuring rocks, gravel, sand, mud, and extreme articulation and you can imagine how these components must be engineered. They are critical to your vehicle’s safety as well. Let’s look at axle shafts in this article. We’ll find out what they are, how to identify when they are faulty, what happens if they break, and how to replace them.
Looking for high-quality drivetrain parts, including front axle replacement parts or CV axle replacement parts? You’ll find it all right here, including axle shafts, driveshafts, differentials, clutches, manual and automatic transmissions, and all the other parts that you’d need for a standard or performance-oriented aftermarket replacement.
What are Axle Shafts?
Axle shafts are tasked with sending torque to the wheels of your vehicle, transferring rotational motion from the differential to the wheels. They can be found on every drive wheel, whether your vehicle is a front-wheel drive, rear-wheel drive, or four/all-wheel drive. These are typically solid steel shafts that are quite sturdy, as they do bear weight in addition to transferring rotational motion.
Axle shafts tend to have CV or Constant Velocity joints at each end to enable the up-and-down motion of wheels as the suspension works its way up and down, as well as the sideways movement necessitated by the front wheels for steering. These Constant Velocity joints are packed with grease, and protected by CV boots. These prevent the CV joints from receiving damage from road or trail debris and keep the grease free from contamination that can occur under relatively common conditions, such as driving over a puddle of water.
Signs of a Faulty Axle Shaft
So how do you know if your axle shaft is faulty? There are a few symptoms that can signal a worn axle shaft. Note that not all of them may signal that the shaft itself is faulty, but the CV joint may have gotten worn down or abraded due to an impact, or breached axle boot that allowed contamination and deterioration of the grease. On some vehicles, if the issue is with the CV joint, you can replace this part only, while on others, the entire axle shaft assembly, inclusive of CV joints, may need replacement. The signs to watch out for are:
- Clicking or grating sounds as you drive along, especially when navigating turns with some steering lock. This is most apparent on the front axles.
- Signs of grease leaking out from the CV joint onto your wheels and tires or skid plate of your vehicle.
- On some vehicles, you may be able to see a breached axle boot, as the CV joint will have a shiny appearance due to the absence of grease after a leak.
- Excessive vibrations while driving appear to get stronger at speed. In severe cases, your vehicle might not be drivable or safe at highway speeds.
What Happens When Your Axle Shaft Breaks?
When your axle shaft breaks, you will definitely feel, and hear it. After all, a solid piece of rotating metal dropping off your vehicle while in operation isn’t going to be silent. Axle shafts don’t usually break without warning, so you’ve most likely encountered the symptoms we described previously, and ignored them at your peril.
After the initial shock, your vehicle will start to veer to one side as one wheel will lose power. If you’re at highway speeds, the pull might be particularly prominent, in which case we advise you to maintain your composure, and focus on bringing your vehicle to a smooth stop in a safe place.
Can you drive on a broken axle shaft? Mechanically, yes, your car will move, but it will most likely be driven by only one wheel (on a 2WD vehicle), and not safe due to the pull towards one side. Your best, and safest course of action is to call for a tow and take your vehicle straight to a competent garage. If the broken shaft is interfering with other moving parts, you might be stuck on the side of the road.
Steps to Replace
Replacing an axle shaft is a reasonably advanced job. There are plenty of competent shops that can do it properly and safely. However, if you have some experience wrenching on your vehicle and feel that you can take it on, this is how it goes. Of course, you should have your new axle shaft, or drive assembly, as well as your tools on hand before starting.
- Remove your vehicle’s wheels in the same way you would to change a flat tire. Your car will be jacked up off the ground. Do it one side at a time, for comparison’s sake, in case you forget how things should go back on.
- Have a buddy on hand to help you.
- Loosen the axle nut with the correct socket and a breaker bar for leverage.
- You might need to remove the brake assembly on some vehicles; in this case, refer to your vehicle’s owner’s manual for this process.
- Remove the cotter pin and castle nut, and disconnect the steering knuckle ball joint with the relevant tool, typically a picker fork. Swing it out of the way for ease of access.
- Gently wedge a tool such as a flat screwdriver between the axle and transmission and slowly pry it out, taking care to not damage the transmission seals.
- The drive assembly will slide out. Ensure that you study its orientation and insert the new drive assembly in the same manner.
- Grease all splines before insertion with gear grease, and re-install everything in the reverse of the disassembly process. Don’t re-use the old cotter pins, but install new ones.
Everything to Keep Your Vehicle Running Smoothly at 4 Wheel Parts
Whether it’s an axle shaft or any other component, 4 Wheel Parts is committed to offering our customers the very best high-quality products. Shop online or in-store for a massive selection of parts from top brands. Enjoy extremely competitive prices, top-notch expert advice, and robust after-sales service.
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