What is the best time to change differential fluid? (& Fluid Change Cost)

Vehicle maintenance can be overwhelming. Many drivers forget to check the fluid level. If you don’t know how often to change the differential fluid, you could easily cause damage to your vehicle.

We will discuss how to maintain your vehicle. Also, we discuss the price of differential fluid and how it affects the vehicle's overall cost. You can also learn how you can change your differential fluid yourself if you prefer to do it yourself.

What is the best time to change differential fluid?

The normal interval for replacing the front differential fluid in your vehicle is between 25,000 and 35,000 miles. You might need it to be changed every 35,000 to 66,000 miles for the rear differential fluid. The appropriate schedule for your vehicle can be found in the owner’s manual. 

A front differential is usually housed in the same housing as the transaxle of an all-wheel-drive or front-wheel-drive vehicle. Therefore, it should be replaced more frequently than the rear. Since they share the same fluids, both differential and transaxle fluid will have to be changed simultaneously.

The changing interval between the front and rear is more frequent when you drive the car harder, or under extreme conditions. If you are in doubt, talk to your local mechanic about what’s best for your vehicle. 

What is Differential Fluid?

For front-wheel drive vehicles, the differential is an integral part of the transmission. However, rear- and four-wheel-drive vehicles have a transmission that’s connected to the drive axles with the driveshaft. A differential is a combination of several gears that distributes the engine's torque across the axle. High-viscosity oil is used to lubricate the differential. 

If the fluid isn’t changed when it should be, the fluid starts to break down. The fluid loses viscosity and the inner gears become worn. That’s why you want to change the fluid at regular intervals.

RELATED: 5 Symptoms of a Bad Differential (Repair & Replacement Cost) 

Price to change a different fluid

It doesn’t cost a lot to change the differential fluid. The average differential fluid change will cost between $75-$175 and the fluid would be $25-$75. If you are unable to do it yourself, the rest would go towards the labor. 

These are only estimates for changing one differential's fluid. If you are driving a four- or all-wheel-drive vehicle, the cost might be double what we’ve estimated. 

Factors Affecting Differential Fluid Change Cost

1. There are many differentials

Some cars have a single differential at the rear. You will pay less to replace the fluid of one differential than you would for two. You may also see a middle differential in some cars that requires fluid changes.

It can also be labor intensive to change the fluid at the front than it is at the back. Because of the number of components in this area, it can make these parts more difficult to reach. If you have to get around the car’s steering rack, you will pay more for labor. 

READ MORE: Open vs. Limited Slip Differentials (What’s the Difference?)

2. Locator/Labor Rate

The labor rate will vary depending on the location. Certain parts of the nation have higher labor rates than others. In addition, labor rates in the country are often lower than those of the cities.

You will also save money if your car is taken to the local lube station than it would if you went to the dealer. However, you get what you pay for, with less experienced technicians working on your vehicle when you don’t visit a shop with certified techs. 

You can save money by doing it yourself. You can save money if you are skilled and have the right equipment to replace the differential fluid. 

READ MORE

3. The amount of gear oil required

The price of differential oil is the same as motor oil. You will pay more for synthetic oil. You will also pay more for different properties and consistent oil. Each differential may call for a different oil type, so make sure you pay attention. This is illustrated by the F-150 truck. The rear might take one gallon of 75Wx140, while the front only needs a ½ gallon of 80Wx90.

You also need to think about how much differential oil you will require. Different axles have different amounts of gear oil. Most vehicles will only need one gallon of oil per change. This information can be found in your service manual. 

RELATED: Rear Differential Noises: Diagnosis, Prevention (& Repair Costs)

What is Differential Fluid Change?

It is easy to change the differential fluid on almost all vehicles. That’s why it’s a common task done at home by the novice mechanic. The steps are generally the same, though they might differ depending upon your vehicle.

1. Verify the fluids. Before you get started, it’s best to check the fluid. You want to see if it’s contaminated or needs to be topped off. If the fluid still looks new, there’s no reason to change it prematurely.
2. You should inspect the housing for any leaks. You need to ensure that the housing is free from leaks before you proceed. Before you replace the fluid, fix it if there are any. The new fluid could leak if it isn't. You may need to install a new gasket, which isn’t a big deal and is often necessary after many years of use. 
3. The system should be drained. The drain plug should be removed and the oil should run to a pan. Before you move on, wait until the oil has completely dried out. You should also inspect the fluid to make sure there’s no sign of metal contamination. You can dispose of old oil at your local auto repair shop, recycling center or auto parts retailer.
4. Fill the tank. You can refill the system once it is fully drained. You can add the right amount of oil and then double-check that the levels are correct. 

As with any car maintenance task, it’s best to take the vehicle for a test ride after you drain and replace the fluid. You can check everything works as it should by doing this simple task. If there’s a burning smell, any weird noises or strange vibrations, there could be larger problems that you need to deal with. If you're unsure of how to proceed, have a professional inspect the differential. 

Avoiding Differential Fluid Changes

Many people put off changing the differential fluid because it doesn’t seem important at the time. This is an important aspect of maintaining your car. If you don’t change the fluid at regular intervals, the gears in the axle can become damaged. Old fluid can also cause wear to the seals.

The fluid can contain dangerous metal. The gears will be damaged if any metal is found in the fluid. It is more costly to replace gears than it is to change the fluid frequently.