Why Does Gear Oil Smell So Bad?

By Shaira Alano Written by Shaira Alano
Updated on March 23, 2022

Gear oils, or also known as transmission fluid, are very important especially in the line of machinery and other vehicles. These are mainly used to secure urbane functioning, longevity of transmissions and shift cases. Transmission fluid serves various purposes such as greasing, preventing corrosion, tarnish, and wear. In addition to this, it also corrects the viscosity, protects and ensures that the metal surfaces are clean. Lastly, the transmission fluid controls the temperature within your transmission.

The horrible smell that we smell when we sniff gear oils is actually from the sulfuric compounds it contains. In addition to this, an overheating gearbox and an expired gear oil would also cause a foul odor. Using an expired oil tends to emit foul odors because there will be burning upon contact between metals due to friction.

Why Does Differential Fluid Smell So Bad?

Actually, when it comes to car problems, gear oil’s health is not the first thing that comes to the minds of the drivers. This is because drivers would usually prioritize other issues such as those related with the oil change, brake pads, and new tires over issues with regards to their car transmission. The transmission fluid suggested by the manufacturer is highly recommended to be followed and this information can be discovered in the manual. We must thereby consider transmission services as an essential method to ensure one’s vehicle’s health. Considering how to keep a good transmission and what you can do to make sure that your dispatch is running ideally can make a vast difference in the life of your car.

The gears inside the differential are the ones that cause the drive wheels to spin at various rates. It is termed as differential mainly because the inside wheel tends to rotate at a slower speed as compared to the outside wheel. Similar to the engine oil, the gears inside the differential require a film of oil for lubrication. This is also to prevent the teeth on the gears from wearing out quickly. Again similar to any engine oil, the differential fluid must be changed at proper intervals as recommended by the service manual.

Differential oils tend to extrude unpleasant odor due to its sulfur compounds that are usually incorporated in high pressure lubricants. Because of this, differential oils smell like rotten eggs or even worse depending on the amount of additives being put on. If you are sensitive to this type of smell, a good precautionary measure is to wear clothes that can be disposed of right away.

Does Gear Oil Have a Smell?

Similar to differential oil, gear oil also contains sulfur compounds hence, innately making the gear oil smell awful. It is better to take it off briskly because this odor can make you sick.

Generally speaking, any kind of burning odor imminent from your vehicle is a source for concern. Heating or low transmission fluid could be a potential root of this burning odor. Natural transmission fluid would usually smell nice or sugary. When that odor turns charred, it means that your transmission fluid has worn out and the system is overheating, directing to a rise in abrasion and corrosive events in the engine. This issue may be resolved by regularly flushing the transmission fluid or by modifying or repairing the leakage. If left unsettled, the transmission could in the end damage itself leading to its complete disintegration.

What does Gearbox Oil Smell Like?

It may look odd to inhale your transmission fluid, but you can identify a lot of issues concerning its health by doing so. A newly-changed transmission fluid should be odorless if not somewhat sweet. If your transmission fluid is smoldered, it will smell more like a burnt toast. Certainly, if your transmission fluid smells smoldered, you must not only obtain a transmission flush but also have your cooling system be examined by a mechanic since your transmission is probably warmed too much.

As mentioned before, the oils in the gearbox contain sulfur that causes them to emit an unpleasant odor similar to that of a rotten egg, or worse. Moreover, if the transmission appears to be overheating, a burning odor is usually being emitted.

How Do You Get Gear Oil Smell Out of Your Car?

Resolving transmission issues, including transmission fluid discharge and modifying low, flared or ineffectual fluid is not that difficult. Nevertheless, you need the help of an automated transmission professional or mechanic to provide you with the repair services of your vehicle. You can effectively examine and change the transmission fluid in addition to fixing any discharge on the transmission without causing any issues later on.

A transmission fluid that must be changed regularly is something you must be more concerned about rather than the volume. If the transmission fluid smells smoldered or looks brownish, then you need to obtain a new transmission fluid. If it is red with no smoldering smells, then the fluid is fine.

In fact, most manufacturers of automatic cars would recommend changing the transmission fluid every 100,000 to 150,000 miles your vehicle had run. However, some mechanics would advise to have it changed every 60,000 to 75,000 miles instead. On the other hand, manual transmission fluid must be changed every 30,000 miles or at the most, 60,000 miles.

Through regularly changing the transmission fluids, we may resolve the various unpleasant odors it emits as well as preventing the escalation of sludge and metal shavings.