Can I Use 75w90 Instead Of 80w90? (quick answer!)

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Because of the similar additives and different viscosities, a lot of people ask ‘can I use 75w90 instead of 80w90 gear oil and what’s the Difference Between 75W90 And 80w90?’

Gear oils are very essential for smoother transmission and protection of your gear systems’ internal components. It is very important to know what’s the Difference Between two of them to choose the right gear oil for your vehicle. Both these oils have the same additives but their viscosity is the main difference that defines both these oils’ different working temperatures.

If you are thinking about using 75w90 instead of the recommended 80w90 gear oil, you need to know if it will be good or not. So, read the comparison and review of both these gear oils below.

Here is a table of specifications for both 75w90 and 80w90 gear oil that can help you understand these oils specifications and differences:

SAE Viscosity Grade75w9080w90
Kinematic Viscosity (40°C)110139
Kinematic Viscosity (100°C)19.215
Pour Point-49°F/-45°C-22°F/-30°C
Flash Point410°F/210°C395°F/202°C
Type Of OilSemi/full syntheticConventional mineral type Oil (multi grade)

Difference Between 75w90 and 80w90: (5 key Differences)

Understanding the differences between 75w90 vs 80w90 is not so easy. You won’t be able to point out the differences just by looking or reading their specifications.

1. Operating Temperature

The 75w90 gear oil is enhanced with thermal stability and oxidative resilience which allows it to operate smoothly at high temperatures. 75w90 gear oils can easily withstand up to 300F-350F temperature. Its winter suitability is also quite efficient. This oil’s flow is smooth and strong till -40°F.

The 80w90 oil can operate in even more tough environments. This gear oil has a better pour point and resistance which allowed it to work smoothly up to +400F temperature which is astounding. Even if you drive in cold temperatures then 80w90 is still a better option as it can withstand cold temperatures till -20°F.

2. Viscosity

Viscosity mainly refers to gear oil’s thickness. Gear oils need to maintain a sensitive and constant thickness at certain temperatures for maximum performance. 80w90 gear oils need more adjustment since they are liquid-based oils. This type of oil takes time to get thick in lower temperatures which can affect its performance.

The 70w90 oils provide a constant thickness/ viscosity since they preserve a wide variety of temperatures. This means that you won’t face any problem with this oil no matter how cold the temperature is because of its longer draining cycles and viscosity.

3. Density

The density of oil also measures how thick the oil is. The more density your gear oil has, the thicker it is. 75w90 gear oil’s density is 0.86 while 80w90 gear oils density is 0.90. Being thicker, 80w90 gear oils can provide your vehicle’s gear system with more protection than 75w90 oils.

Despite providing protection, 80w90 gear oils can’t perform well on lower protections. On the other hand, 75w90 oils are thin and efficient to work in any extreme condition. 75w90 oils also provide some protection facilities for the gear system’s components which makes its density ideal for performance and protection.

4. Additives

In the case of additives, both 75w90 and 80w90 would get the same ratings even though they have specialties in different sectors. 75w90 gear oil has non-foaming additives and adhesive coats for gear protection. This adhesive is strong enough to protect gear components from intense strain.

75w90 gear oils can perform smoothly even in extreme pressure and temperatures without requiring any lubrication. On the other hand, 80w90 gear oils contain anti-wear and heat control additives which also work in the same way. Both these gear oils are perfect for heavy-duty, off-road, and racing cars.

5. Price

75w90 gear oil is more expensive than 80w90 gear oil. 75w90 is a versatile oil that can be used in almost any vehicle and it is balanced for any pressure and temperature. So, it’s worth buying 75w90 oil by paying some extra money.

85w90 oil is also a great choice for its price. This oil provides all protection with the smooth performance you can want within this price.

Here are reviews of 2 of the best 75w90 and 80w90 gear oils.

Best 75w90 & 80w90 gear Oils – Top Recommendation

Valvoline SynPower SAE 75W-90 Oil

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Improved Synthetic Engine Oil:

If you are looking for a gear oil that ensures less noise and smoother transmission, there is no better option than Valvoline 75w90. Being fully synthetic, this gear oil offers lower evaporation and flammability along with improved viscosity and oxidation resistance.

Great Operation with Thermal Stability:

Valvoline SunPower SAE 75w90 full synthetic gear oil is considered to be one of the best gear oil for performance, thermal stability, and protection. This oil is especially popular for use in cold temperatures where it can easily withstand intense pressure and with its high viscosity.

Additional Additives:

The special additives used in Valvoline 75w90 gear oil helps to protect your gear system’s components from rust and corrosion. This oil also helps to reduce gear teeth’ chattering which can make your transmission very comfortable smooth.

Who Is This For?

The thermal stability of Valvoline 75w90 gear oil is very reliable. It performs excellently in both extremely high and low temperatures. You won’t feel any discomfort or roughness in your transmission no matter how extreme pressure this oil needs to withstand.

Valvoline SAE 80W-90 Gear Oil – High-performance Synthetic Oil

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Flexible Synthetic Oil:

Valvoline high-performance SAE 80w90 is a multi-purpose gear oil that can also be used on axels of spiral and gears. You can use this gear oil for service fillets, refills, and top-offs. This 80w90 gear oil provides astonishing thermal flexibility and long-term oxidation resistance.

Enhanced Protection:

The extreme pressure additives used in Valvoline 80w90 gear oil helps to minimize gear wear. This oil also has a very strong resistance to foams which makes it the ideal API GL-4 gear oil. It will also protect your gear from scuffing, corrosion, pitting, and engine wear.

Operates in Any Temperatures:

80w90 gear oil of Valvoline is also suitable for both high and low temperatures. This oil is thin enough to operate the gearbox smoothly at low temperature and high pressure. Its superior additives used for protection against severe temperatures are the same as the Valvoline 75w90.

Who Is This For?

You can smoothly operate your vehicle’s gear at high torque, horsepower, load, and high-speed conditions with Valvoline 80w90 gear oil. Most importantly, this oil comes at a very reasonable price.

Is It Worth It To Use 75w90 Instead Of 80w90?

Before using 75w90 oil instead of 80w90, you should know if it’s going to be beneficial for you or not. 75w90 is more expensive compared to the price of 80w90. So, you must get better protection and transmission smoothness with 75w90. 

80w90 gear oil can provide high-temperature protection and performance ensuring reliability at a reasonable price. If you are still willing to pay more for 75w90, it will be worth it because 75w90 is an overall balanced gear oil that will protect and ensure gear performance in every condition.

No matter what pressure your gear faces, 75w90 can handle it without degrading performance or requiring any lubrication. Your gear components’ smoothness and protection will be much more reliable with 75w90 in both extremely low and high temperatures. So, it is undoubtedly worth it to use 75w90 gear oil instead of 80w90.

people also ask

1. Is It OK To Use 75W90 Instead Of 80W90?

Yes, it is absolutely fine to use 75w90 instead of 80w90 gear oil. You can use 75w90 oil without facing any problems or performance drops even if it is recommended to use 80w90 gear oil with your vehicle.

2. Is 80W90 The Same As SAE 90?

80w90 and SAE 90 are almost the same. SAE 90 is equivalent to 50wt engine oil which is similar to 80w90 gear oil so you can technically say that these two are also the same.

3. Can You Mix 75w90 And 80w90?

You can mix 75w90 and 80w90 because they don’t have so much difference in density and viscosity. You can also mix conventional and synthetic oils of different viscosities and different weights.

Mixing two oils will produce a new viscosity which will be between the two mixed viscosities. Mixing 75w90 and 80w90 won’t affect protection or performance in any way.

Relevant post:

closing thoughts

Now that we have answered the question ‘Can I Use 75w90 Instead Of 80w90?’ You must have understood that it is okay to use 75w90 if you want. 80w90 oils are denser which means that you will be able to get better performance in high temperatures and more gear protection.

On the other hand, if you want smooth and versatile performance in all pressures and both extremely high and low temperatures, then 75w90 is unbeatable. If the higher price isn’t a problem then you can surely use 75w90 instead of 80w90.

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Mahir Ahmed


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