An Axle’s Role In The Drivetrain

An axle is an integral component in a car’s drivetrain. An axle delivers power from the differential to the wheels and is the reason a wheel has the ability to spin. Axles are found in every vehicle and come in three standard types: front, rear and stub. Axles can be found in the front and rear of vehicles and can have different functions depending on what type of drivetrain the vehicle has. If you want to learn more about a vehicle’s drivetrain as a whole, check out the article What You Need To Know About 2 Wheel Drive

Different Types Of Axles

Rear Axle

A rear axle is usually a live axle, meaning the axle rotates with the wheels. The axle delivers driving power to the wheel via differential. Rear axles come in two parts typically referred to as half shafts. There is a half shaft on each end of the differential, which sits in the middle of the shafts. One end of the shaft connects to the sun gear on the inside of the differential and the other end connects to the wheel. These axles have several different variations depending on what functions they need to perform. Here are the 3 different sub classes of rear axles:

  • Semi – Floating 
  • Full – Floating 
  • ¾ – Floating 

Front Axle

Front axles come in two different types: 

  • Live Axle
  • Dead Axle 

A live axle provides power directly to the wheels like you would find in a front wheel drive vehicle (as well as most rear wheel drive vehicles). A dead axle does not receive any power from the drivetrain and just spins as the wheels spin, an example of a dead axle would be the two front axles in a rear wheel drive vehicle. The front axle is similar to the rear axle but instead of connecting directly to the wheel it connects to a universal joint on the inside of the steering knuckle. On the other end of the universal joint is a much smaller axle known as a spline shaft that connects to the wheel bearing. The use of the universal joint allows the front wheels to articulate and turn without the axle binding. Since the rear wheels do not have to turn they do not require a universal joint. The front axle needs to be able to support the front wheels in moving up and down or in and out, so they need to be made with very strong materials and with laser precision. 

Stub Axle 

Stub Axles are different from the first two types because they only support one wheel. They are used on the non-driven wheel hubs and are connected to the front or rear axle by king pins. In front wheel drive cars it can be used in one end of the rear axle. In rear wheel drive cars, it is used on both ends of the front axle. There are four subtypes of stub axles: 

  • Elliot 
  • Reverse Elliot 
  • Lamoine
  • Reverse Lamoine

Signs of Failing Axle

There are a few signs to look out for when your axle assembly is nearing the end of its life and they are all equally important. 

Signs Your Axle Is Failing:

  • When in drive/reverse and or while turning you hear a clunking noise
  • When in drive/reverse you feel an unusual vibration in the steering wheel or floorboard
  • When in drive/reverse while accelerating the vehicle does not move 

Although these issues do not always mean the axle is the faulty part in your car, these are all things to pay attention to while driving and the axle should be looked at immediately if noticed. Fixing these issues before they completely break can help you in many ways. When an axle  completely breaks you will be stranded wherever you broke down and your vehicle will not move. A complete axle break can also cause immense damage to other components of your vehicle. Depending on the safety features in your vehicle, a completely broken axle could cause the wheels to completely lock up meaning they will stop spinning even if you are in motion. You can imagine the amount of damage that could be done if this happens at higher speeds. That is why it is important to replace these faulty parts before they cause more hardship than necessary.

What To Do When Your Axle Fails

When your axle begins to fail or immediately fails it obviously means one of two things: it is time for a replacement axle or time for a new car. Luckily, we know how you can solve both of those issues. My Auto Store is a used auto parts store that sells OEM parts that will match your exact make and model. So, if you broke your axle or if it is making strange noises, replacing it can be affordable. Instead of buying a brand new axle for a used car, buy a used one that is put through a rigorous inspection process for a much better price. My Auto Store puts all their car parts through a 4-step quality control process before they list them in their inventory! This way you can ease your mind about buying a used auto part. They also offer free shipping and a 6 month warranty on all online orders, another bonus! 

If you make the more expensive decision of buying a new car, you will need some extra cash to put a down payment on one. My Auto Store can also help with this! You can sell them your old vehicle that was damaged for a fair price. They also price match against competitors, if you give them proof of a competitor quote, they will match or beat it! This way you get some cash in your pocket and that broken down car off your hands at the same time. 

Whatever you decide to do, do not let these issues go long without fixing, it will save you a lot of money in the end.


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