If you’re like most car owners, you probably don’t think about your differential fluid until there’s a problem. And by then, it can be too late! That’s why it’s important to be aware of the symptoms of low differential fluid levels.
The symptoms of low differential fluid levels include a noisy differential, difficulty shifting gears, and increased wear on your drivetrain components. If you notice any of these, have your differential checked by a qualified mechanic.
This blog post will also discuss some tips for safely and efficiently replacing differential fluid. Stay tuned!
Table of Contents
What is Differential Fluid? Why do You Need it?
Differential fluid, also called gear oil, is a special type of lubricant designed specifically for differential gears. Differential gears are used in the drivetrains of many vehicles, including cars, trucks, and SUVs.
The differential allows the wheels to rotate at different speeds while still providing power to the wheels. This is necessary because when you turn a vehicle, the inner wheels have to travel a shorter distance than the outer wheels.
Differential oil helps to keep the differential gears cool and operating smoothly. It also helps to protect the gears from wear and tear. Not only that, but it is also essential in providing lubrication to the clutch plates.
You should change gear oil according to the manufacturer’s recommendation along with other essential fluids, including engine oil, brake fluid, and power steering fluid.
Symptoms of Low Differential Fluid
Several symptoms can indicate low differential fluid levels. The most common ones are:
- Loss of Traction While Turning
- Grinding or Humming Noise
- Overheating Differential
- Slipping Transmission
- Burning Smell
- Excessive Vibrations
- Uneven Tire Wear
Let us dig deeper into each of these symptoms, shall we?
1. Loss of Traction While Turning:
This is likely the most dangerous symptom of low differential fluid. When you make a turn, the inside wheels have to travel a shorter distance than the outside wheels.
The differential helps to compensate for this by transferring power from the outside wheels to the inside wheels. If there is not enough differential fluid, this process will not work properly, and you may lose traction.
This can be extremely dangerous, especially if you are making a turn at high speeds.
2. Grinding or Humming Noise:
If the differential fluid level is low, it can cause strange noises. These noises ranging from grinding, humming, squeaking, and squealing, may be coming because there is no differential fluid to lubricate the gears properly.
This can cause the gears to grind and make noise. Additionally, a low differential fluid level can also cause the wheels to slip and produce a squealing noise.
3. Overheating Differential:
One of the most common symptoms of low differential fluid is overheating of the entire differential. This can happen for several reasons.
Firstly, if the fluid level is low, there is less fluid available to cool the differential bearings and gears. This can lead to increased friction and heat build-up, which can eventually cause the differential to fail.
Secondly, a low fluid level can also cause the differential to overheat by not allowing enough lubrication to reach the gears and bearings. This lack of lubrication can again lead to increased friction and heat build-up, eventually causing the differential to fail.
4. Slipping Transmission:
Another symptom of low differential fluid is a slipping transmission. If the differential fluid is low, it will not be able to provide enough lubrication to the clutch plates. This can cause the transmission to slip and may eventually lead to complete failure.
The function of gear oil is to lubricate the gears and bearings inside the transmission, as well as act as a hydraulic fluid to power the automatic shifting mechanism.
If the oil level is low, it can cause the gears to grind against each other, which will cause transmission slippage. In addition, the lack of hydraulic pressure will make it difficult for the transmission to shift gears properly.
5. Burning Smell:
If you notice a burning smell coming from your vehicle, it could be due to a low differential fluid level. When the fluid level is low, it can cause the gears to grind against each other.
This increased friction will generate heat, which can cause the oil to break down and start to burn. This burning smell will be most noticeable when the vehicle is first started after sitting for some time.
6. Excessive Vibrations:
Another symptom of low differential fluid is excessive vibrations. One of the main reasons low differential fluid levels can cause excessive vibrations is because it can cause the gears to become misaligned.
When the gears are misaligned, they will not mesh correctly, and this will cause a lot of friction. This friction will lead to the gears wearing down prematurely and eventually breaking.
If the differential fluid level is low, it will also cause the bearings to wear out prematurely. This can cause even more vibration because the bearings will not be able to spin as freely as they should.
Bad sway bar links can also cause vibrations but they are more likely to be felt on the steering wheel.
7. Uneven Tire Wear:
One of the most common symptoms of low differential fluid is uneven tire wear. This is because the differential helps to distribute power evenly to the wheels.
If it is not properly filled, one wheel may receive more power than the other, causing it to spin faster and wear down more quickly. Uneven tire wear can also be caused by other factors such as incorrect tire pressure, misaligned wheels, or a bent axle.
What Causes Differential Fluid to Get Low?
There are a few different reasons why your differential fluid level might get low. Let’s discuss some:
1. Burning of Differential Fluid:
The most common reason for a low differential fluid level is simply because the fluid has been burned off. Over time, the differential fluid will break down and start to burn.
This is especially true if you do not regularly change your differential fluid. When the fluid breaks down, it will cause the gears to grind and create heat.
2. Leaking Seals:
Another reason why your transmission fluid leak when parked is because of broken seals. Over time, the seals in your differential can become worn and start to leak.
This will cause the fluid to slowly leak out over time until it eventually gets low enough that it starts to cause problems.
3. Vehicle Sitting For Too Long:
Another common reason for a low differential fluid level is that the vehicle has been sitting for too long. If you do not drive your vehicle often, the differential fluid can start to break down and burn off.
This is because the fluid is not being circulated, and it is not getting hot enough to evaporate any moisture that might be in it.
4. Not Checking the Oil Level Often:
One of the most common reasons for a low differential fluid level is simply because the owner does not check it often enough.
It is important to check your differential fluid level at least once a month. This will help you catch any problems early on and prevent them from worsening.
Where to Check for Gear Oil Leaks?
There are five places in total from where the differential oil can leak. These spots include:
1. Input Shaft Seal:
This seal is located where the driveshaft enters the differential. It can start to leak over time due to wear and tear.
2. Output Shaft Outer Seal:
This seal is located on the outside of the differential where the driveshaft exits. It can also start to leak over time due to wear and tear.
3. Output Shaft Inner Seal:
This seal is located on the inside of the differential where the driveshaft exits. It is less likely to leak than the outer reak axle seal, but it can still happen.
4. Differential Cover Gasket:
This gasket is located between the differential cover and the differential itself. It can start to leak if it is not properly sealed or if it becomes damaged.
5. Drain Plug or Fill Plug:
The differential has a drain plug and fill plug used to add or remove the fluid. These plugs can sometimes become loose and start to leak. Check out these as well!
How to Check Differential Oil Level?
It’s important to check the differential oil level regularly and top it off as needed. Here’s a step-by-step guide to checking your differential oil level:
- Park your car on a level surface and set the parking brake.
- Locate the differential fill plug on the side of the differential housing. The fill plug is usually a large hex head bolt.
- Place a drain pan beneath the differential housing to catch any oil that may drip out when you remove the fill plug.
- Using a wrench, remove the hex fill plug.
- Clean the area around the fill plug hole with a rag.
- The fluid level should be even with the bottom of the fill hole.
- Secondly, check for the color and consistency of the differential fluid. If it’s dark and muddy, it needs to be replaced.
- If all looks good, reinstall the fill plug and tighten it to factory specifications.
- Wipe up any oil that may have dripped on the underside of your vehicle.
How to Replace the Rear Differential Fluid?
If you notice any of the above symptoms, or if it’s been a while since you’ve replaced your differential fluid, it’s time to change it. Here’s a step-by-step guide to replacing your rear differential fluid:
- Park your vehicle on a level surface and set the parking brake.
- Locate the fill plug and drain plug on the differential housing. The fill plug is usually a large hex head bolt, while the drain plug is usually a smaller hex head bolt.
- Place a drain pan beneath the differential housing to catch any oil that may drip out when you remove the plugs.
- Using a wrench, remove the fill plug and drain plug.
- Allow all of the old fluid to drain out of the differential.
- Clean the area around the fill and drain plugs with a rag.
- Insert the drain plug back into the differential housing and tighten it to factory specifications.
- Fill the differential with new gear oil until it reaches the bottom of the fill hole. You can use a funnel to help you pour in the oil.
- Insert the fill plug back into the differential housing and tighten it to factory specifications.
Differential fluid is an important part of your vehicle’s operation. It helps to keep the gears lubricated and running smoothly. If the fluid level gets low, it can cause some serious problems.
Checking and replacing your differential fluid is a relatively easy task that you can do at home. It’s important to do this regularly to keep your car running smoothly and prevent any major problems.
We hope you found this article helpful. Please feel free to leave a comment below if you have any questions or suggestions. Thanks!
Frequently Asked Question
What happens if differential fluid is low?
If the differential fluid is low, the first thing you’ll notice is probably a reduced level of traction. This happens because the differential relies on fluid to keep its gears properly lubricated.
When the fluid level gets low, the gears can start to grind against each other, which makes it harder for the wheels to turn. You might also notice some strange noises coming from the differential area if it’s low on fluid.
What is the average cost of differential fluid change?
The average cost of differential fluid change is between $80 and $170. The cost can vary depending on your vehicle type and where you take it to get the work done. Differential fluid changes are typically not something that people do themselves, so it is important to factor in labor cost when budgeting for this type of maintenance.
The fluid itself only costs around $20 to $60, but the rest of the cost is labor. Differential fluid changes are typically done as part of a larger service, so the total cost will be higher if you need other services simultaneously. For example, an oil and differential fluid change may cost around $140.
Can you drive without differential fluid? How Long?
You might be able to squeeze a few hundred miles out of a car with low diff fluid, but it’s not advisable. Differential fluid is important for the proper functioning of your vehicle’s differential.
Without it, your car will be unable to properly distribute power to the wheels, resulting in decreased performance, poor lubrication, and possibly even damage to the differential itself. Driving without differential fluid can damage the differential and lead to costly repairs.
Are gear oil, differential oil, and transmission fluid all the same?
The terms gear oil and differential oil are exactly the same. However, transmission fluid and gear oil are not. Although both perform the same function, they have different chemical compositions.
The main difference between the two is their use case. Gear oil is a term devised for lubricant used in manual transmissions and differentials, while transmission fluid is designed for use in automatic transmissions. You must use the correct fluid if you have low differential fluids.
How often should you check the differential fluid level?
You should check differential fluid levels at least once a year or every 30,000 miles. However, it’s best to check it more often if you do a lot of driving in off-road or mountainous conditions.
These conditions put extra stress on the differential and can cause the fluid level to drop more quickly. It’s also a good idea to check the fluid level if you notice any strange noises coming from the differential area.
What are different types of differential fluids available on the market?
The most common type of new differential fluid is the conventional gear oil. This type of fluid is typically made from petroleum-based oils and can be used in most differentials.
There are also synthetic gear oils, which are designed to provide better performance and protection in extreme conditions. These types of fluids can be more expensive, but they may be worth the cost if you do a lot of off-roading or driving in harsh conditions.