Your car’s differentials are the unsung superheroes, quietly working their magic to keep your vehicle performing at its best. And don’t forget about changing the differential fluid!
Although you may not do it often, it will keep the components well lubricated and prevent premature wear and tear that leads to more expensive repairs or even replacement.
In this article, we are going to look at what differential fluid is, why it should be changed, and what happens when you change it infrequently or ignore it altogether.
Why is Differential Fluid Important?
Differential fluid, otherwise known as gear oil, is vitally important to your vehicle. It lubricates the gears in the differential, which reduces friction and wear on those gears.
When you turn corners, you have a differential, which allows your wheels to rotate at different speeds, which provides smooth handling and stability.
The greatest feature of this fluid is that it not only serves as a lubricating oil for the gears but it also dissipates heat generated by the gears while protecting them from corrosion and rust.
Properly lubricating the gear oil being filled allows the differential to run properly and reduces wear.
You find differentials in all cars; sometimes a differential in a car can be located on the rear side of the vehicle, and sometimes on the front side. Some cars can have a differential in both sides (some cars can have a rear differential and a front differential – each of which has specifications on what oil to use).
If you have an incorporated transaxle with a front differential and a rear differential, they will have different oil requirements.
Typically, if a car has a front differential and an incorporated transaxle, the front differential will run a fully synthetic oil (SAE 75 to 85). The rear differential will run with thicker oil than SAE90.
How Often Should the Rear Differential Fluid Be Changed?
Most manufacturers recommend changing rear differential fluid around every 30,000 to 60,000 miles. Check your vehicle’s owner’s manual for the specific mileage amount.
If you drive your vehicle hard, this interval will be even shorter. Most manuals have a section labeled “severe driving conditions” that will list a shorter interval if you have any of the conditions listed in your environment and use.
When you change the fluid, pay a licensed mechanic to do it first, so you don’t screw anything up. Plus, it’s mostly dirty work, and you want the differential fluid to be disposed of properly.
For instance, some differentials have a drain and fill plug that would make it easier to change the fluid. Some might require a new gasket, and the parts in the differential housing must be cleaned when changing the fluid to remove the contaminants that may be left behind from the previous fluid.
We do not want the contaminants to mix in the new fluid because that will cause problems.
How Often Should Front Differential Fluid Be Changed?
As with fluid in any manual transaxle, if your front differential shares a housing, you could be changing it every 25,000 to 30,000 miles. Still refer to your owner’s manual to accurately confirm what’s on your specific vehicle.
The front differential shares fluid with the manual transaxle, so you are changing both at the same time.
Like the rear differential, unless you are familiar with changing the fluid in the front differential, this work should only be done by a certified mechanic.
If you determine to change the differential fluid yourself, be warned, it is a messy job. Gear oil is thick, smells horrible, and won’t wash off your clothes easily.
In some cases, the rear differential has a drain plug to remove oil; others have a housing cover that is removed instead.
Have a wide catch pan ready and place a plastic drop cloth underneath it. Get in your vehicle and drive it around the block for a couple of minutes, if you haven’t done so already, so that the oil will be warmed up.
Then change into some work clothes and prepare to get dirty. If the gear oil is at or near temperature, it would be advisable to wear gloves to prevent burns.
Or, if you wanted to avoid the hassle of getting dirty, you could hire the mechanic to do the job. Plus, with a real mechanic (over a friend), you would have peace of mind knowing that the job will be done right, and therefore have a slightly higher chance of safety with less potential for mistakes.
Cost of Changing Differential Fluid
Changing the differential fluid is not too pricey. The fluid itself costs between $20 and $80, and labor will run around $60 to $120.
In all, you’re generally looking at a bill around $80 to $200 to change your differential fluid, depending on your car, where you go, and how much differential fluid it requires.
In most cases, to fill each differential, you will require anywhere from 1 quart to 4 quarts of oil (again, dependent on your specific vehicle).
Keep in mind that the pricing above is only for one differential housing. If you have all-wheel drive, your cost could double based on your mileage/mile interval.
Problems of Not Changing Differential Fluid
Not changing your differential fluid can ultimately lead to multiple issues. Like engine oil, gear oil is important in reducing friction in your vehicle’s entire transmission system.
There will be issues that begin to arise the longer you ignore this maintenance.
To show an example, friction will rise as the fluid becomes less effective. The wear of your truck’s differential and transmission components can easily be prevented.
Gearing a wear on gears means money down the line. When the parts grind against each other with a lack of lubrication, they are prematurely wearing down.
Another possible these noises could signal an issue, like a whining noise from the differential.
This noise will be a signal that the fluid should be changed before further damage can happen to the transmission area.
So, for the purposes of your vehicle performing nicely and the longevity of the vehicle’s components, changing the differential fluid when the vehicle manufacturer requires it will prevent issues along the way.
FAQs.
Q: How Long Does a Differential Fluid Change Take?
If you are having a dealership, independent mechanic, or quick lube like Jiffy Lube change your differential fluid, it would typically take anywhere from 30 minutes to 1 hour in most cases. If you are doing it yourself, it will typically take 1-2 hours for the average person.
This includes draining the old fluid, flushing the differential if that’s necessary, and refilling the differential with new fluid. Time frames may vary depending on where you go and the particular complexity of your vehicle’s differential system.
Q: Does the Type of Vehicle Affect the Fluid Change Interval?
Absolutely! The type of vehicle does play a role in how often you should change your differential fluid. For the average vehicle, the manufacturer’s recommendation is to change the fluid every 30,000 to 60,000 miles.
However, the specific intervals may change depending on the type of vehicle (make and model) and how the vehicle is used, whether it is for towing, off-road activities, etc.
For example, if you are driving a performance vehicle or a vehicle with a limited-slip differential (or electronic limited-slip differential), you should change the fluid more often, especially if you are driving it hard as these types of differentials may be exposed to much more stress and wear.
Likewise, trucks and SUVs that are used for towing, or off-road, should have the differential fluid changed more consistently to achieve the best optimal performance and longevity for the vehicle.