Does Changing Differential Fluid Make A Difference? (Know The Fact)

Most cars, SUVs, trucks, and automobile owners have less knowledge about changing the differential fluid. They rarely know about their vehicle’s differential and its fluid change. So it’s commonly ignored until they face poor performance from their vehicles due to low, no, or gunk differential fluid. 

Does changing differential fluid make a difference?

Undoubtedly, yes. Changing differential fluid based on vehicle manufacturer recommendations offers you a huge benefit. The differential fluid change will prevent differential components friction, overheating, noise, tire slipping, and differential failure.  

Since most of you won’t know much about your automobile’s differential, its fluid changing interval, how to change the differential fluid, and what it costs, here we have rounded up all of those things for your convenience. Trust us, the time you spend reading this post won’t be wasted. 

What Is A Differential? 

A differential is a three-drive shaft containing gear and a pinion train. Which have different rotational teeth to allow your drive wheels independently move at different speeds during turning, cornering, or hopping. 

Does it sound harsh to you? Don’t worry; here’s a simple description. 

While turning, your car’s inside wheel travels less space than the outside wheel. So the outside wheels have to spin faster than the inside wheels to cope up the space. The differential works here to maintain this high and low-speed level to keep your control over your car. 

What Is Differential Fluid? 

Differential fluid is slightly thicker than regular motor oil. When the gear ring,  pinion gear, clutch packs, and differential bearing rotate, they come in contact, and for continuous friction, they generate heat. The differential fluid comes from the driveshaft and lubes all the metallic parts to prevent friction and reduce the heating of the components.  

When To Change Differential Fluid? 

There is no hard and fast time limit to change the differential fluid as it mostly depends on the manufacturer. Moreover, four-wheeler vehicles have front and rear differentials and need fluid at different times. It’s better to check your vehicle’s manufacturing manual to know the exact miles of changing its differential fluid. 

Front And Rear Differential Fluid Change

However, let’s see the general mileage of an automobile’s front and rear differential fluid change. 

Front differential fluid change

In most cases, you have to change the front differential fluid at least every 30,000 to 50,000 miles based on your vehicle.

Rear differential fluid change

The rear differential fluid serves you a longer time than the front differential fluid. It needs to be changed within 30,000 to 60,000 miles considering its condition. 

But, is it always true to change the differential fluid according to that mileage range? There is a bigger no. 

The differential fluid changing interval may be longer or shorter according to your car driving habit. The more you drive, the shorter the interval and the less you drive, the longer the interval. 

Low Differential Fluid Symptoms

The above mileage range is general for most of the differential fluid changes. But, there are plenty of factors to determine when to change the differential fluid. Actually, these are the signs of low differential fluid. 

Excessive grinding

If the diff fluid is low, it can’t properly lube the diff components. So, all the metal parts of your diff area (gears, bearings, and pinion) come in contact and grind. 

Wired tire spinning

When the diff oil is low, your vehicle’s tires will spin unusually. So wired tire spinning will cause serious damage to your vehicle, and even lead to severe accidents, which is not expected. 

Overheating differential

There are many factors of differential overheating, including wrong types of fluid, low fluid, gunk oil, excessive bearing preload, overloading equipment, and worn bearings. 

Once you notice the difference in your differential heating, you must confirm it as a low fluid sign. 

Strange noise

Due to metallic friction, wired tire spinning and overheating, the differential may produce strange howling, humming, or whining noise from either both or a single differential. You may notice a gradual changing of these noises when pressing the accelerator, decelerator and during cornering, 

Unusual Vibrations

When you cruise early in the morning or on a sunny afternoon, you may get unusual vibrations from the front wheels. It means the differential fluid is either low or worn out.

Oil burning smell

The diff oil starts to burn when it gets lower than usual. So if you perceive a burning oil smell from your vehicle’s transmission, you have to consider it as a low diff fluid sign.  

What Happens If You Don’t Change Differential Fluid? 

When the excessive grinding, wheel-wired spinning, and overheating continue for a longer time, they cause significant damage to the differential. If you ignore all those signs and never change the differential fluid, it leads to differential failures.

How To Check Differential Fluid?

Checking differential fluid level isn’t a hard job, as you can check it with your finger. Open the differential fill fluid plugs with a ratchet wrench and insert your index finger into the service port. Slightly bend your finger downward to reach the oil level. If you can touch the gear oil, there is enough oil inside. If not, the oil is lower than regular, and you have to change it. 

That’s the snippet on how to check the front differential fluid. Below, we’ll discuss the differential fluid changing process. Look at these procedures to know the details about checking differential fluid levels. 

How To Change Differential Fluid?

If you notice any or a few diff low fluid signs, you have to change the differential fluid. You can change the differential fluid as you change the manual transmission fluid.

However, the steps may vary from vehicle to vehicle, as some come with two differentials while others come with one. Also, some vehicles have one plug to fill and drain oil, while some have two plugs, one for draining old black oil and one for filling new oil. 

But, you have to be prepared with some tools and equipment that you’ll need to change the diff fluid. Here’s the list of them

The Things You’ll Need

• A jack stand
• A flat screwdriver
• A ratchet wrench
• The manufacturer recommended new fluid
• A drain pan
• Hand gloves, goggles, and old clothes 

Step 1: Lifting vehicle 

First, wear your safety gear to prevent yourself from getting messy. Now, lift the vehicle with a jack to reach its underneath and the differential fluid plugs. Firmly stand your vehicle on the jack stand. 

Step 2: Find the diff fluid plugs

Try to find the square or hexagonal-shaped diff fluid fill and drain plugs. If they are covered with a housing, you need to pry it with a flat screwdriver to reach them. 

Step 3: Drain the old fluid 

If there is oil drain and fill plugs, first release the drain plug with the wrench. But before that, place the drain pan exactly underneath the diff drain plug. If there is low fluid, the pan can carry the drained old, black, and gunk oil.  

Step 4: Secure the drain plug 

When all the old oil is drained, and you are sure there is no old fluid, fasten the plug that you released. 

Step 5: Fill the diff fluid 

Now release the oil fill plug, and with a fluid hose or pump, fill the new oil into the differential reservoir. But don’t overfill, as it may increase the chance of the plug’s oil leaking. 

Step 6: Secure the fill plug

When the diff oil is changed, fasten the differential fill plug, and replace the housing. 

Step 7: Remove the jack stand 

Finally, carefully remove the jack stand from the vehicle and release it. Now start your engine, and notice if everything is ok. 

Note

If you don’t like to do this messy work yourself or are short of time, it’s better to take professional mechanical help to change diff fluids. As they have years of experience and knowledge, you’ll get the best service from them. 

Front Differential Fluid Change Cost

No matter which diff fluid you change, that doesn’t cost you an arm and a leg. You’ll need 1 to 4 quarts of fluid to fill the diff depending on the vehicle to vehicle and model to model. However, different types and ranges of differential fluids may cost you around $30 to $80. If you change the fluid yourself, the fluid price is your only cost. 

But if you take professional help, their charge will be added with fluid cost. In that case, the cost may increase from $70 to $150 based on your vehicle, location, professional expertise, etc. 

FAQs 

Can low differential fluid cause vibration?

Yes, low differential fluid can cause vibration due to a lack of lubrication, friction, and overheating. 

Can low differential fluid cause slipping?

Yes, low differential fluid can cause slipping transmission. When the diff fluid is low, the clutch plates of the diff won’t get enough lubrication and become slippery. 

Can I drive with no differential fluid?

No, you can’t drive without differential fluid, even though you shouldn’t think of it. Because if you drive with no or low differential fluid, it brings a lot of hazards for you. Metal-to-metal rubbing and excessive friction, engine overheating, irregular noise, burnt oil smell, and permanent differential failure are some of the consequences of no diff fluid driving. 

Conclusion 

Now you know changing differential fluid can make a big difference in your flued system. Even you also know low diff fluid signs, fluid changing interval, cost, and process. So don’t drive your car with low or no differential fluid to avoid damaging it permanently.