Differentials are found in all cars. Sometimes a differential may be found on the rear side of a vehicle and sometimes it’s found on the front side. Some cars even have differentials on both ends.
If you have a front differential in your car with a transaxle built in, then the rear differential will use a different type of oil.
Usually, when a vehicle has a front differential with a built-in transaxle, it will require a fully synthetic oil (like Oil SAE 75 to 85). As for the rear differential, it will need a thicker oil that’s around SAE 90.
Unlike changing your engine oil, the change interval for differential fluid is fortunately much longer. That said, it’s an often overlooked task where spending a little now is a much better alternative to the cost of repairing a differential.
How Often Should the Rear Differential Fluid Be Changed?
The recommendation of most car manufacturers is that you change your rear differential fluid about every 30,000 miles to 60,000 miles. Look at the owner’s manual of your car to find the exact mileage amount.
This interval gets shorter the harder you drive your vehicle. Most manuals have a “severe driving conditions” section that will give you a shorter interval, if any of the listed conditions apply to your specific environment and use case.
When you are ready to change the fluid, have a licensed mechanic do it so that you don’t mess anything up. It is a dirty job and the differential fluid needs to be thrown away properly.
Some differentials have a drain and fill plug to make the process easier. In some cases, a new gasket will need to be installed and the differential housing parts will have to be cleaned of any existing contaminants that may still be there from the older fluid. That way, these contaminants won’t get mixed into the new fluid and cause problems there.
How Often Should the Front Differential Fluid Be Changed?
If your front differential shares a housing with a manual transaxle, your front differential fluid may need to be changed as often as 25,000 to 30,000 miles. Again, check the owner’s manual to confirm the exact mileage amount for your specific vehicle.
Since the manual transaxle and front differential share the same fluid, you’re changing them both at the same time. As with the rear differential, the front differential fluid should only be changed by a licensed mechanic unless you’re comfortable performing this yourself.
If you do plan on changing differential fluid yourself, be prepared to undergo a messy job. Gear oil is thick, smells pretty bad, and it won’t come out of your clothing very easily. While a drain plug exists in some rear differentials, other rear differentials have a housing cover that needs to be removed instead.
Have a wide catch pan ready with a plastic drop cloth underneath it. Turn on your vehicle and drive it around the block for a couple of minutes so that the oil can be warmed up. Then, change into some work clothes and get ready to get dirty. If the gear oil is at or near operating temperature, it’s a good idea to wear gloves so you don’t burn yourself.
Of course, you could just hire a mechanic and save yourself the trouble of getting dirty. Plus, going to a professional will ensure the job is done right so that you have more safety and less risk of mistakes being made.
Differential Fluid Change Cost
Changing differential fluid isn’t too expensive. The fluid itself can cost between $30 and $80, and labor will run between $40 and $70. All together, you’re looking at somewhere in the range of $70 to $150 to change your differential fluid depending on your vehicle, where you take it, and how much differential fluid it needs.
To fill up each differential, you’ll need anywhere from 1 to 4 quarts of oil in most cases (again dependent on the vehicle model).
Note that the cost above only applies to a single differential housing. If you have all wheel drive, you may need to double the cost depending on your maintenance interval.