How to Change Differential Fluid

Last Updated: December 21, 2021 References

Like any lubricant, the fluid in an all-wheel drive or four-wheel drive vehicle’s rear differential will eventually break down and need to be replaced. In most applications, the fluid in your rear differential should be replaced every 12,000 to 50,000 miles to ensure the gears within are properly lubricated.^{[1]
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Research source
www.vehiclemd.com/purring-or-roaring-the-often-forgotten-differential-service/} Replacing differential fluid at regular intervals will prolong the lifespan of the vehicle. This project requires only common hand tools and a container to catch and seal the old fluid in.

Part 1

Part 1 of 3:

Locating the Differential

1
Purchase the right differential fluid. It is extremely important that you determine the correct type of differential fluid for your vehicle. Ask the clerk at your local auto parts store to help you find the correct fluid to use.^{[2]
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- Be sure to provide the year, make and model of your vehicle to get the right fluid.
- Your vehicle’s owner’s manual should also indicate the correct type of differential fluid to use.
2
Jack the car up. Be sure the vehicle is parked on a level surface that is strong enough to support the weight of the vehicle centralized beneath the jack. Black top or concrete are the optimal surfaces. Slide the jack beneath the vehicle at one of its designated jack points and use the handle to jack the vehicle up off the ground.
- If you are unsure of where the designated jack points are for the rear of your vehicle, refer to the owner’s manual for guidance.
- Never jack up a vehicle on grass, gravel or dirt.
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3
Support the vehicle with jack stands. Never work beneath a vehicle that is supported only by a jack. Once the vehicle is jacked up to a sufficient height, slide jack stands under the vehicle at another designated jack point.
- Jacks may lower the vehicle unexpectedly while you’re beneath it.
- Lower the vehicle onto the jack stands slowly to ensure they are positioned correctly.
4
Locate the differential and drain bolt. The rear differential is located between the two rear wheels of the vehicle. While it is not always located directly in the center of the vehicle, it is usually close to the middle. The differential may resemble a basketball or a pumpkin, prompting some to refer to it as “the pumpkin” of the vehicle.^{[3]
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- Along the bottom of the differential there is a bolt that can be removed to drain the fluid.
- The drain bolt will resemble the one you might remove from an oil pan to drain the oil from the engine.

Part 2

Part 2 of 3:

Draining the Differential

1
Place a container beneath the differential. Make sure you have a sealable container to catch the old differential fluid as you drain it from the vehicle. Place the container beneath the drain bolt so the fluid will pour into the container once you remove it.
- Used differential fluid will need to be brought to a certified recycling location.
- Do not mix old differential fluid with oil or gasoline.
2
Remove the drain bolt. Use a hand or socket wrench of the appropriate size to turn the drain bolt counter-clockwise to loosen it. Once the bolt is hand loose, use your hand to unscrew it while applying pressure inward to keep it from leaking as you loosen the plug. Once it is completely unthreaded, pull the plug away and let the fluid pour out.^{[4]
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- You may want to wear gloves to avoid getting old differential fluid on your hands.
- Make sure the vehicle is cool when doing this otherwise the fluid may burn you.
3
Allow the fluid to drain completely. It may take a few minutes for the differential fluid to drain out completely. Make sure the container is positioned properly and does not overflow as the fluid drains out.
- Allow the differential to drain until there is only a slow drip of fluid remaining.
- Seal the container once the differential has finished draining for storage and transport to a recycling center.
4
Replace the drain bolt and wipe down the area. Once the differential is empty, use your hand to thread the drain bolt back into place, then use the wrench to tighten it until the differential is once again sealed.
- Do not overtighten the drain bolt. It only needs to be tight enough to provide a seal.
- Be sure to use the correct size wrench to avoid stripping or damaging the head of the bolt.

Part 3

Part 3 of 3:

Refilling the Differential

1
Locate and remove the differential fill bolt. With the differential drain bolt in place, locate the fill bolt near the top of the differential. In some vehicles, you will not be able to see it easily, but you should be able to feel it if it is on the top. Many vehicles now place the filler bolt on the back side of the differential for easier access.^{[5]
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- Use a hand or socket wrench to remove the filler bolt.
- Set the bolt aside some place safe so you don’t lose it as you fill the differential.
2
Insert a pump into the differential fluid. Use a hand pump to fill the differential with fluid. You will not be able to pour the fluid directly in because of the angle. Hand pumps come in a number of varieties and will allow you to pump the fluid out of the container from beneath the differential.
- Open the seal on the top of the differential fluid and insert the inlet hose or tube for the hand pump.
- Be careful not to tip the differential fluid over with the pump as you get situated beneath the differential.
3
Slowly pump the fluid into the differential. Crank or pump the hand pump to introduce new fluid into the differential. Continue to pump until you reach the maximum capacity listed in the vehicle’s owner’s manual or until you see fluid start to seep out of the filler hole.
- You can purchase hand pumps at most auto parts stores.
- Check the automaker’s website for maximum capacities if you do not have an owner’s manual.
4
Replace the fill bolt. Once the differential is full of new fluid, replace the filler bolt with your hand, then tighten it using the wrench. Ensure the filler and drain bolts are both secure and wipe them down with a rag so you will be able to identify any leaking in the future.
- Take the vehicle for a short drive, then check to ensure neither bolt is leaking.
- If you spot a leak, tighten the bolts and wipe them down again.

Community Q&A

Question

How often should I change the differential fluid?

Community Answer

Most people never do. It should be checked periodically, and topped off as necessary. There is a fill hole on the side of the box, and the oil should come up to the side of the hole. Check your car owner's manual if you want to change it in order to determine the intervals that it should be checked and changed.
Question

How much should it cost on average to change the differential fluid?

Community Answer

All you will need to purchase for this project (assuming you have the tools) is the differential fluid. There are a variety of options to choose from that may range in price from as little as $10 to as much as $50, depending on the application and brand.
Question

Will replacing the rear end fluid make my vehicle quieter?

Community Answer

It may, but it depends on whether the noise is from the differential, the U joints, or even the wheel bearing/hub. It couldn't hurt to change it though.

Warnings

To check your brake fluid reservoir, open the hood of the car and take a look at the fill lines.^{[6]
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Expert Source

Jason Shackelford
Auto Technician
Expert Interview. 11 June 2019.}

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A "soft" brake pedal is usually one of the first symptoms that your differential fluid is running low. You may or may not get a light on your dashboard.^{[7]
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Expert Source

Jason Shackelford
Auto Technician
Expert Interview. 11 June 2019.}

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