Car Axles – How to identify and inspect your car’s axles

We explain the different types of axles on a modern car and how to inspect your axles for common issues.

A car axle is a simple machine that applies the mechanical effort of the combustion engine to transfer the energy produced by the engine to turn the wheels that are attached to an axle. The axle and wheels are 360° levers as shown in the animation below.

Courtesy of Eureka!

By Maurice Rodriguez
August 1, 202

What is a car axle?

This mechanical advantage allows us to move heavy objects by applying the weight of the object on an axle attached to wheels. The wheels allow us to multiply the force being applied by the combustion engine to easily move a car. This is enhanced by the gears which accelerate the car even further.

Some common examples of wheels and axles can be found all around you in:

  • Steering wheels
  • Door Knobs
  • Fishing Pool Reel
  • Electric Fan

All of these simple machines multiply the number of turns made to create a larger force thereby giving us a mechanical advantage. The greatest application of this simple machine is by far the invention of the horse and carriage which we all know led to the horse-less carriage – the modern car. Without this humble achievement by man to ease the burden of moving heavy cargo by applying 360° lever we would have never been blessed with the invention of the automobile.

In this post, we will talk about what types of axles are currently being used by most car manufacturers, what the differences are among the different types, and how to inspect an axle for damage so you can stay on top of the maintenance of your car.

Types of car axles

Car axles come in different types and designs based on their specific engineering need. Some axles merely must bear the weight or load they are carrying. Others are split to allow for better suspension and turn at different speeds when going around corners. We will cover some of the different types, purposes, and how to identify them.

  1. Straight Axle – A straight axle is the simplest most basic kind of axle. It usually consists of a large solid steel shaft that connects the two wheels. This kind of axle has been in use since the Romans started using them in their chariots. It is used as a load-bearing axle meant for large loads like those found on a locomotive, large semi-truck, and some off-road vehicles.
  2. Tandem Axle – A tandem axle is typically a set of two or three straight axles on large trailers meant to disperse the weight of a heavy load allowing it to carry more weight efficiently. 
  3. Split Axle – This is the most common axle found today. The split axle is often used on front-wheel and rear-wheel drive cars. This axle gives engineers the ability to have independent suspension for a smoother more comfortable ride. It also lends itself well to the use of mechanical differentials, which allows each wheel to turn at a different speed when going around corners.

Dead vs Live Front Axles

  1. Dead Front Axle – these axles are still used today in train cars, and front-wheel drive cars where the only purpose of the dead axle is to support the wheels but have no power.
  2. Live Front Axle – These axles transmit power and are typically connected to a drive shaft that connects to a differential or transfer case.

Types of Rear Axles

  1. Semi-Floating Axles – These axles are engineered for light-duty weight-bearing applications like a four-wheel drive trucks, SUV’s and sedans. These axles are less expensive than full floating axles because of the lower cost of materials to produce. They are used to bare the weight of the vehicle while the axle shaft provides power to the wheels.
  2. Full Floating Axles – are designed to be bare more weight from the load as the outer casing supports all the weight. They also resist torsional deflection under a high load application like off-road or racing.

How do I know if I have a bad axle?

CV Joint Axle in action

CV Axle – How do you know if it’s bad?

A CV Axle on most front-wheel drive cars is an axle shaft responsible for transmitting power from your transaxle (the transmission under your engine that sends power to the wheels).

The best way to inspect a CV (constant-velocity) Joint axle is to do a visual inspection yourself or by a certified mechanic. Some of the signs that you have an issue are:

  • Worn out Boots – Visually inspect the boots for damage, rips, or tears. The boots are made of durable rubber and should be free of any debris, grease, or tears.
  • Clinking Sounds – When making turns, do you hear an audible clicking sound? This is one of the first signs that your CV joints need to be inspected.
  • Grease on Tire – Are you seeing excessive grease on the inside of your tires or on the CV joint? The CV Joint needs to be lubricated to function correctly. If you see grease collecting around the boot you will have to replace the CV joints
  • Vibration while driving – if the axle shaft is damaged it may vibrate while rotating and cause excessive vibrations as you drive.

How Much to Fix a Car Axle?

How much does it cost to repair your axle? This depends on if the axle or CV boot needs to be replaced. On average the repair will be $200 to $400 for a single CV Joint and $600 to $1,100 for an axle shaft replacement.

Make/ModelAdvanced Auto PartsRock AutoO’ReillyAverage Estimated LaborAverage Estimated Total
2012 Ford Focus $199.91

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2013 Ford Escape $240.67

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2016 Toyota Camry$90.99

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2013 Hyundai Elantra$89.73

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2011 Chevy Equinox$86.99

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While wheels and axles are very simple machines they have been reimagined by modern engineers to serve a facet of uses in front-wheel drive cars, off-road vehicles, commercial semi-trucks, and motorcycles. They are the most used simple machine application in use today. Without the wheel and axle, many of man’s achievements would never have been possible.

We are all things cars.

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