How to know your car needs a diff oil change

The differential (aka ‘diff’) in your car has a very important role in keeping you safe on the road. So it’s crucial you know what it is, signs it may be failing and when to change your diff oil.

Let’s look at what a diff is, its crucial function, when to know to change your diff oil and more. And if you need any advice, give our friendly team at mycar a call.

What is a diff in a car?

A differential, or ‘diff’, is part of your car’s drivetrain, helping to deliver power from your engine to your wheels. When you change the direction of your vehicle (so, steering left or right), the diff determines the rotational power and speed needed, and then sends the required power to each axle shaft to complete and control the turn.

There are four types of diffs:

1. Open differential, which is the most common, simple and reliable design

2. Locked differential, a variant typically used for off-road vehicles

3. Limited slip differential, which is a combination of open and locked diffs

4. Torque vectoring differential, which is the latest in diff technology

The diff you need depends on your vehicle and what you’re using your car for, such as performance, off-road or everyday driving.

What is diff oil?

Diff fluid or oil, sometimes known as gear oil, helps keep your differential in peak condition, and is found in the axle housing. As well as cooling and lubricating the differential, the fluid lubricates the clutch packs, bearings, ring and gears that enable power to transfer from the driveshaft to the wheel axles.

Does changing differential fluid make a difference?

Changing diff oil is incredibly important. Like any car fluid, oil doesn’t last forever and can run out. When diff oil is low or runs out, there is no lubrication to stop the gears from grinding, which creates heat, leading to differential failure.

Differentials also do not have a filter, like motor oil. So, when the gears start to grind together, small metal shavings or pieces may appear. As a result, major damage is done to the diff. Not only is this expensive to repair, it is also a huge safety risk as you no longer have control of your turns.

What are the symptoms of needing differential fluid change?

If you’re worried about the state of your diff, chat to the friendly mechanics at mycar. Otherwise, here are some things to look for to know when to change diff oil:

How to change diff oil

It is possible to change your diff oil yourself. But if you don’t really know your way around a car, it’s probably best to call your local mycar mechanic.

You’ll need to do a few things before you start. You’ll need:

You will also need to check your wheels and potentially raise your car for easier access. Once you have your essentials, in most cases, this is how to change your diff oil:

1. Take a drive to warm the differential as this will make it easier for the oil to drain.

2. Park your car on a flat, level surface, with your transmission in park or gear. This is when you want to chock your wheels and raise your car.

3. Crack the filler plug to ensure it won’t get stuck when your diff is empty.

4. Place the drain pan under the drain and remove the drain plug. Take note of the colour of your diff oil or a strong burning smell, as it may mean you have some damage to also deal with.

5. Replace the drain plug, using a torque wrench to secure it in place to factory specifications

6. Pump the recommended amount of oil through the filler hole or as recommended by your manufacturer’s manual

7. And you’re done!

Of course, not everyone has the time, space or want to change their own diff oil. If this is you, our mechanics at mycar are here to help.

How often to change diff oil

How often you should change differential oil depends on the car and manufacturer. Due to the time between changes, it’s not typically included in logbook servicing, but should be included in major servicing.

The ideal diff oil change interval

Your differential oil change interval depends on the manufacturer of your vehicle, but is typically most passenger vehicles are around 90,000KM, and 4WD’s much sooner, between 40,000KM and 50,000KM

What happens if you never change your differential fluid?

If you never change your differential fluid, you will start to notice strange sounds and bad smells from your car, before your diff will inevitably fail.

This is not only costly to fix, and highly preventable, but can also be dangerous as you won’t be as in control of turning your vehicle, especially at high speeds.

What happens if your diff runs out of oil?

If your diff runs out of oil, the gears will begin to grind, which will overheat the diff and lead to failure. Failure of your diff means you no longer have the right amount of power being delivered to your axles, and you would not be in control of your vehicle, potentially leading to an accident.

When that oil runs out, your gears will seize, your rear wheels will lock up and you won’t be able to turn at all. So, it’s just better to change your diff oil when needed or at least ensure you’re booking in for your major services!

Need a diff oil change or diff repairs near you? Call mycar!

We know things happen, and usually at the worst possible time! The team at mycar are here to help you get back on the road, whether that’s by giving your diff some TLC, or handling any other aspect of your car’s needs. Plus, we’re totally transparent on price, so you always know what the bill will be!

Our expert mechanics are here to help with your diff oil changes and diff repairs, all backed by our workmanship guarantee. You can even get the work done when you need, with Afterpay and Zip available across hundreds of stores.

So book your diff repair or oil change with your local mycar today! We’re here to help.