Skip the auto shop - Our mechanics make house calls

How to Check Your Car’s Differential Fluid

mechanic checking out differential fluid

Ever since you got your driver’s license, you’ve been to told to check your engine oil. But what about the fluids underneath your vehicle? If you’ve got a rear-wheel drive, four-wheel drive, or all-wheel drive vehicle, chances are, you have a differential under your vehicle.

diagram of a differential

Through the use of pinion gears, the differential allows the wheels to turn at different speeds while cornering to prevent skidding.The differential is also where the final gear reduction in the drivetrain takes place and where torque is transmitted to the wheels. The amount of torque a differential delivers depends on the ratio of two internal gears: the ring and the pinion.

Differentials require gear oil for proper operation. This oil lubricates and cools the internal gears and bearings. It’s a good idea to check your differential fluid level if there is any sign of an external differential leak. You’ll also want to check the level if the differential has just been serviced. Here’s how you go about checking the differential fluid on your ride.

Part 1 of 2: Checking the fluid

Materials Needed

  • Basic hand tools
  • Oil drain pan
  • Protective gloves
  • Repair manuals (optional)
  • Safety glasses

If you choose to get a repair manual for reference, you can look up your vehicle’s make, model, and year through sites like Chilton. Autozone also provides free online repair manuals for certain makes and models.

differential fill plug picture

Step 1: Locate the differential fill plug. Generally, the fill plug is located on the differential or the differential front cover. The plug may be either hex- or square-shaped.

hand loosening the plug

Step 2: Loosen the differential fill plug. Put an oil drain pan under the differential and loosen the differential fill plug with the appropriate tool.

Some fill plugs are loosened with a ratchet and socket, whereas others, those with square female inserts, are loosened with a ratchet and extension.

hand removing the fill plug

Step 3: Remove the differential fill plug. Remove the differential fill plug.

Fluid should run out. If it does not, the level is low and fluid should be added.

Part 2 of 2: Adding the fluid

Materials Needed

  • Basic hand tools
  • Differential fluid
  • Oil drain pan
  • Protective gloves
  • Repair manuals (optional)
  • Safety glasses

hand adding additional differential fluid

Step 1: Add the differential fluid. Add the appropriate fluid to the differential until it starts to trickle out.

Most differentials use gear oil but the weight varies. The fluid type can be found either in your owner’s manual or the vehicle repair manual. A parts store can also look up the fluid type for you.

had reinstalling differential fill plug

Step 2: Reinstall the differential fill plug. Reinstall the fill plug and tighten it down with the tool used in Part 1, Step 2.

Tighten it until it's snug, or look up the exact torque specs in the vehicle repair manual.

That’s it! Now you know how to check more than just the under-the-hood fluids. If you would rather have your differential fluid changed or inspected by a professional, the mechanics at YourMechanic offer expert differential service.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem...
How to Transfer a Car Title in Idaho
In order to prove ownership of a car, you must have the title. However, when a car is sold, given away or inherited, the title needs...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...


Related questions

Q: what is the capacity of the differential and capacity of the transmission. fluids?

Hello, thanks for writing in about your Nissan Altima. The transaxle takes 7.88 quarts of Nissan CVT fluid NS-3 only. If you need assistance with having your transmission and differential fluid, consider YourMechanic, as one of our mobile technicians can...

Q: I have a 2003bmw 525i , I mistakenly put tranny fluid in the power steering canister now it is hard 2steer what 2 do now

Hello, thank you for writing in. While it is not terribly uncommon to run transmission fluid in the power steering system (they are both hydraulic fluids), newer vehicles tend to be designed to be used with specific fluids, and do...

Q: Mileage is very low;

If you have not had any maintenance done then have a complete computer scan test done to see if any codes are present. Perform any maintenance needed like air filters, fuel filters, and oil changes. You didn't mention the mileage...