Signs Of Low Differential Fluid – Inspection And Replacement

Differential fluid is a familiar term to many drivers and automotive enthusiasts, acting as an essential lubricant facilitating the operation of many gears inside your car.

But what are some signs of low differential fluid? Keep scrolling down for further information!

What Is The Differential Fluid?

Signs Of Low Differential Fluid

Differential fluid is the oil specially designed for lubricating internal engines or components of the entire differential gear.

If you are in the dark about the latter, it is a motor part responsible for controlling the shifting capacity and direction of the vehicle’s back wheels.

This oily liquid ensures the constant working of the differential in peak conditions for a while and provides optimal protection from wear and tear.

The list of functions as follows will help you comprehend more:

  • Lubricate the differential bearings, gears, and clutch plates.
  • Grease the pinion rings, which transfer power from the driveshaft to the wheel axles.
  • Alleviate the excessive heat generated during the differential’s operation, which is mainly attributed to metal-on-metal contact.
  • Help users save lots of money, as their differential gears may be better protected and require less expensive repair costs.

What Are Some Signs Of Low Differential Fluid?

Below are some common symptoms, like the loss of traction, humming or grinding sound, overheating issue, slipping transmission, burning oil smell, intense vibrations, and uneven tire damage.

Loss Of Traction While Turning Your Wheels

This could be the most dangerous sign, jeopardizing drivers’ safety.

When you approach a corner and make a turn, the outside wheels must span a greater distance than the inside ones do, consuming more power.

That’s why the differential gear is created, reducing the difference between two forces during the turning process.

In case your differential fluid is not enough, this procedure would be hindered, so you could lose traction.

Unusual Noises

Suppose the differential fluid level is low; you might hear strange noises. The reason is that when you turn your vehicle, metal pieces of gear and engines contact each other.

Their interaction becomes more forceful when there is a lack of lubrication, causing louder sounds, such as humming or squeaking noises.

In some situations, the wheels may slip, producing a squealing noise.

Overheating Issue

Overheating is one of the distinct indicators. Concerning insufficient fluid, its capacity to cool the entire differential engines down seems to reduce.

Over time, this results in increased friction and gradual heat accumulation.

When heat builds up to excess, the differential and other motor parts in your automobile are badly affected, working less effectively and getting damaged. Sometimes, your car won’t even start.

Slipping Transmission

Another symptom is slipping transmission. This is because the clutch plates receive poor lubrication due to the lack of differential fluid.

Hence, the automatic or manual transmission would likely slip and lead to complete failure.

Besides, some components of the manual system, including bearings and pinion rings, also need adequate lubricant to run smoothly.

The shortage problem will cause them to grind against one another, inducing transmission slippage.

Burning Smell

If you smell something burning inside your car, there is a high chance that it stems from the engine grinding.

As we have mentioned earlier, a low-gear oil renders the differential to grind.

An increase in friction may follow, generating more heat. The excessive heat will break the oil down, make it smolder, and the burning smell is an eventual consequence.

In this case, you should be careful with the exploding accident by getting out of your vehicle or towing it to a nearby garage for a checkup and repair.

Excessive Vibrations

Intense vibrations are another scenario that might arise when a differential fluid amount is subpar.

This is primarily boiled down to the misalignment of gears. In other words, they are unable to mesh properly.

Lots of friction force is generated and causes the bearings’ premature breakdown. They cannot spin freely as they used to.

The hindrance to moving will lead to more shaking, and you could feel these vibrations more clearly if this issue persists.

Uneven Tire Damage

One of the essential functions of a differential fluid is facilitating the even distribution of power to the car wheels. When it stays low, one wheel can get more power than the other.

Accordingly, it might rotate faster and become more prone to wear. However, tire damage is induced by various factors, such as overloading tire pressure, bent axles, or misaligned wheels.

So it would be best to combine the uneven tire wear with other signs in the list before concluding.

What Are The Factors Behind A Low Differential Fluid?

What Are The Factors Behind A Low Differential Fluid?

Following are four notable culprits behind the nagging problem for you to consider.

Burning Of Differential Fluid

The differential fluid is susceptible to external factors after a while of usage, like temperature or chemical reaction. In turn, its components begin breaking down and smolder silently.

This phenomenon takes a long time, and you find it very hard to notice the change in the oil level with the naked eye.

It is advisable that you need to check it frequently with the prospect of averting worse scenarios.

Leaking Seals

Another rationale behind the issue of a transmission fluid leak lies in the broken seals.

They may be vulnerable to corrosion, as many are manufactured from metals, like steel or bronze, which are the ideal victims of rusting.

Over a period, there are some cracks on their surfaces, causing the fluid to leak outside and lower the total amount slowly.

Your Vehicle Parking For A Long Time

The fluid does not regularly circulate when your car is in a stationary state for too long. That the situation prolongs induces insufficient heat for the differential oil to burn.

The moisture cannot fully evaporate, and large amounts still linger in the fluid, inducing its components to break down.

The Irregular Maintenance

If the owner does not perform the maintenance process frequently, the chances that his gear oil is subject to one of the above culprits are great.

Therefore, it is strongly recommended that your car, especially the differential fluid, be checked by a professional mechanic once a month, so potential problems can be detected promptly.

How To Check The Differential Oil Level?

Here is an all-inclusive tutorial for you:

  • Step 1: Prepare some necessary tools, including a torque wrench, a flashing light, a plier, gloves, and protective eyeglasses.
  • Step 2: Park your car and turn the engine off.
  • Step 3: Locate the fill plug of the differential. In most automobiles, it has a square or hexagonal shape, usually located on the front cover of the differential.
  • Step 4: Place a liquid container under the differential housing to catch excess oil dripping during the procedure.
  • Step 5: Loosen the plug by using a wrench.
  • Step 6: Once the plug is loosened, you can see the fluid on the fill hole’s bottom.
  • Step 7: Clean the surrounding area with the help of a rag and Cataclean (be cautious about some potential problems after using Cataclean).
  • Step 8: Examine the differential fluid by checking its quality, consistency, and color.
    If it shows some dark or muddy hues, replace it instantly. Or else, you only need to reinstall and tighten the fill plug.
  • Step 9: Wipe up all the dripping oil.

How To Replace The Rear Differential Fluid?

Below is a thorough instruction:

  • Step 1: Prepare the necessary stuff and park your automobile carefully.
  • Step 2: Find the location of a fill plug and drain plug.
  • Step 3: Put a liquid container under the differential housing to prevent the oil from dripping on the ground.
  • Step 4: Remove the drain plug and fill plug.
  • Step 5: Thoroughly drain the old oil out of a differential.
  • Step 6: Clean the area which surrounds the fill plug.
  • Step 7: Fill the differential with new fluid. It would help if you used a funnel to avoid pouring it outside.
  • Step 8: Install the fill plug and drain plug into their set positions and tighten them.

Frequently Asked Questions

When Should You Change The Differential Fluid In Your Car?

A normal fluid gets weary after a distance between 30 and 60 thousand miles. However, you should regularly check it once a month.

What Is The Average Cost Of A Differential Fluid Change?

You may have to pay 20 to 60 dollars to purchase the gear oil. Yet, the repair cost may vary, depending on your car’s state. The figure could reach up to 140 dollars.

Could You Drive Without The Differential Fluid? How Long?


You can still drive for about a few hundred meters, but this practice is inadvisable, as it wreaks great havoc on your vehicle in the long run.

The Bottom Line

Hopefully, after reading this article, you will learn more about the signs of low differential fluid and know how to check or replace it.

Once you spot any symptom of improper lubrication, follow our step-by-step guide to inspect the fluid.

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