Differential fluid, also called gear oil, is a lubricating oil that is thicker than engine oil. As a lubricant, differential fluids protect metallic diff components from premature wear and increase their lifespan.
It offers a seamless driving experience when making corners on several road pavements. The diff fluid functions under high pressure to keep the bearings, clutch packs, and gears well-lubricated at all times.
It also ensures the entire differential works smoothly and safely. If water enters the differential fluid, if gets contaminated, or low, it’ll cause catastrophic damages to the differential.
It can also lead to a permanent breakdown. Before damaging the entire differential, it’ll project some symptoms to notify the driver of an imminent problem in the system.
Therefore, this article will focus on the signs of low differential fluid and how to check differential fluids. Take a seat and have a 5-minute read.
What Is The 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.
Importance of Differential Fluid
Understanding the importance of differential fluid is crucial for your vehicle’s performance. This fluid lubricates and protects the differential, ensuring smooth operation during turns and various driving conditions.
Key Functions
Differential fluid serves several essential functions:
- Lubrication: It reduces friction between moving parts, preventing wear and tear.
- Cooling: It dissipates heat generated during operation, protecting components from overheating.
- Protection: It forms a barrier against contaminants, helping to maintain the integrity of the differential.
Without adequate differential fluid, these functions diminish, leading to reduced vehicle performance and potential damage.
Signs 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 Are The Factors Behind A Low Differential Fluid?
Following are four notable culprits behind the nagging problem for you to consider.
#1. 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.
#2. 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.
#3. 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.
#4. 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.
Importance Of Differential Fluid Change
Regular differential fluid changes play a crucial role in maintaining your vehicle’s overall performance and health. Old or contaminated fluid can compromise the functionality of the differential, leading to increased wear and potential failure.
Benefits To Vehicle Performance
Fresh differential fluid improves lubricating properties, ensuring smooth operation of the gears and bearings. Benefits include:
- Enhanced Responsiveness: New fluid reduces friction, allowing for quicker gear changes and better handling.
- Heat Management: Proper lubrication helps dissipate heat, which prevents overheating during operation.
- Noise Reduction: Fresh fluid minimizes the noise produced by the differential components, contributing to a quieter ride.
Impact On Longevity Of Drivetrain
Changing the differential fluid regularly extends the lifespan of your drivetrain. Consider these aspects:
- Reduced Wear: Clean fluid decreases metal-to-metal contact, which lowers the risk of premature wear on gears and bearings.
- Contaminant Control: New fluid eliminates debris and contaminants that can lead to damage over time.
- Increased Reliability: Regular maintenance fosters reliability, reducing the likelihood of unexpected repairs or breakdowns.
By prioritizing differential fluid changes, you maintain both vehicle performance and drivetrain longevity, ensuring a smoother and more reliable driving experience.
Process to Check Car Differential Fluid
It is always a good idea to check the level of differential fluid in case you find any of the aforementioned symptoms or an external differential leak.
If you have an all-wheel-drive, a rear-wheel drive or a four-wheel drive, there is a chance that your car differential fluid is under the vehicle. You can follow this process to check the differential fluid.
If you wish to check gear oil at home, make sure you have the necessary items such as gloves, manuals, oil drain pan, and safety glasses. Follow these steps:
- Step 1: Firstly, you should find the fill plug of the differential. Generally, it is located on the differential front cover and is usually square or hexagonal.
- Step 2: Then you need to release the plug. Once the plug has loosened, place the oil drain pan below the differential.
- Step 3: You may require a ratchet to help with releasing the plug.
- Step 4: Once you have successfully unfastened the plug, the fluid will come out. If it doesn’t, the fluid level is low, therefore you need to add it.
Please note that don’t forget to consult professional help, in case you can’t change the differential fluid in a vehicle. You can dubizzle’s listing of auto accessories and parts for sale in Dubai if you wish to buy differential fluid and other auto parts.
How To Replace The Rear Differential Fluid?
Tools Required
- Socket Wrench Set: For removing differential cover bolts.
- Drain Pan: To catch old fluid.
- Fluid Pump: For adding new differential fluid easily.
- New Differential Fluid: Ensure it meets manufacturer specifications.
- Sealant or Gasket: For resealing after fluid change.
- Torque Wrench: To tighten bolts to recommended specifications.
- Rags or Paper Towels: For cleaning up spills.
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.
FAQs.
Q: What does low differential fluid sound like?
Low differential fluids or worn gears will sound like humming or grinding noise emitting from the diff. These noises will also have gradual changes when taking corners, decelerating, and accelerating.
Any strange noise should be checked by a certified mechanic and fixed as soon as possible before it escalates to a major repair job.
Q: Can I drive with no differential fluid?
First, let’s look at what the differential fluid does to find out if one can drive without it. The diff oil lubricates the gears, bearings, clutch packs. It also oils the ring and pinion gears and the entire differential. Lastly, it cools the diff and prevents it from overheating.
Therefore, if you’re asking, how far can you drive without differential fluid? Don’t even think of it. driving without differential fluid will cause metal-to-metal rubbing, which will lead to excessive friction.
This means the fluid will overheat, burn itself, and pose safety issues. To say but a few, it’ll cause catastrophic damages to the differential.
Q: How long can you go without changing the differential fluid?
The differential is an important component in cars. It compensates for the difference in inner and outer wheels when taking corners. However, it doesn’t require early oil change like the engine oil.
But if the diff receives improper lubrication, you won’t travel far for a long time. Fortunately, a vehicle can run as long as 30,000 to 50,000 miles before requiring a differential fluid change.
Q: What does diff fluid smell like?
A differential fluid smells like transmission oil or like a mechanic’s garage. The diff oil is thick, dark yellow to black, and smells like. a tranny fluid.
If the differential overheats and eventually burns the fluid, it’ll emit a burning smell like burning rubber. Whenever you perceive a burning smell from the diff, have it checked as soon as possible.
Q: What does differential whine sound like?
A differential whining noise when decelerating means there’s a worn-out or loose pinion gear or bearings in the diff. This may sound like a regular or loud whining noise from underneath the vehicle.
Always diagnose your vehicle whenever it starts giving strange noise. If ignored for an extended period, it’ll escalate and drop expensive repair bills on the table.
Q: What happens when you run out of differential fluid?
Driving without diff oil is never advisable considering the major functions of differential fluid – to lubricate and cool the internal components.
When you run out of differential oil, the pinion gears, side gears, spider gears, crown wheels, and other inner components will rub against each other. Consider checking out the symptoms of bad pinion bearings.
At first, the diff will give a howling, whining, and grinding noise. If you continue driving with it, it will cause catastrophic damages to the differential unit.
Q: Is differential oil the same as transmission fluid?
Most motorists use the terms ‘transmission fluid and differential oil’ interchangeably. Is there any difference between them? There are several differences between them, starting from viscosity ratings, heat resistance, and the ability to handle pressure.
However, the fundamental difference between the differential oil and transmission fluids lies in the purpose they are used for.
Differential oils are engineered to work in manual gears. In contrast, transmission fluids are manufactured to work in automatic transmissions.
Q: How much does it cost to change the differential fluid?
Differential fluid change is an easy maintenance job. It involves removing the diff cover to drain the oil, reinstalling the cover, and last, refilling the fluid. You can also call this service ‘transaxle drain and refill.’
Because of its simplicity, it doesn’t cost much to change. The cost to change diff fluid is $80 to $90 on average. When replacing the fluid, the mechanic may suggest other system maintenance.
Final words
Now that we’ve seen the signs of the low differential fluid, what happens if you use the wrong differential fluid? Using the wrong diff fluid will cause poor lubrication, system overheating, and possibly, differential failure.
Even a master mechanic may not reverse the damages by flushing the fluid. It’ll require replacing the damaged components and refilling the diff with the recommended fluid.
Therefore, always watch out for the symptoms of a low differential fluid and resolve it as soon as possible. Check this extensive article on the signs of a failed differential, causes, and fixes.