75w90 Vs 80w90: What Are Their Differences?

Car components can be affected by gear oil and lubricating oils. It helps the gear components run smoothly by protecting them from oxidation, rust, and corrosion.

You can find these gear oils in a variety of weights. The applications of these oils are different depending on their viscosity.

The 75w90 gear oils are compared with the 80w90 gear oils to find out which is better for our needs.

The transmission units work at high temperatures, pressures, and speeds, so they need the proper transmission oil.

Is it right for some people to use 75w90 and 80w90 interchangeably?

These oils are made with the same components and performance enhancers, but their viscosities are different and affect their function under different temperatures.

The consistency of the high viscosity gear oils gives them better performance. This may affect the efficiency of the gear due to the cold and moderate temperatures.

How do you make a decision on which gear oil to use? We only need to know about the 80w90 and 75w90 gear oils.


75w90 Gear Oil

75w90 gear oil is a synthetic gear lubricant made entirely from synthetic base oils and Additives.

The gear oil can be used in applications with extreme pressure. 75w90 is recommended for use in cold climates and limited-slip differentials.

The anti-friction treatment on the 75w90 gear oil is what makes it a high-performance one. This gear oil can be used on a lot of railway gearboxes.

There are amazing load spotting capabilities where surprise loading and severe pressures are expected.

75W90 oil has an excessive viscosity index, oxidation, thermal stability, and a low pour point.

The 75W90 gear oil offers long seal life and excellent film strength maintenance, thus enhancing reliable lubrication, thanks to its excellence in foaming.

80w90 Gear Oil

80w90 synthetic oil can be used as a lubricant for non-synchronized manual transmissions for buses and trucks.

The 80w90 is good for limited slip and conventional differentials. The 80W90 has different grades. The W shows how stable the oil is.

The 80 shows that the oil works well in cold temperatures, while the number 90 indicates the 80w90 gear oil’s thickness at 100% degrees Celsius.

The kinematic viscosity of 80w90 gear oil is between 13 and 18 square millimeters/second. The oil is resistant to heavy loads and features high shear stability.

Thinner oils can work more smoothly in low temperatures. You can use 80w90 synthetic gear oil on gears, the axles of spirals, and some manual transmissions.

The gear oil has strong resistance to foams and protects parts against oxidation.


Even though they are all in liquid form, the gear oils are not the same. The use of gear oil can be determined by its grade or number.

80w90 and 75w90 gear oil have different usage, configuration, ingredients, and other things you can’t see.

Let us see what makes the difference between 75w90 and 80w90 different.


The difference between 75w90 and 80w90 gear oils is in their thickness. Since they have a better viscosity, gear oils have historically been used by fleet operators and proprietors.

Even in highly challenging situations, gear oils can be used to maintain the machinery.

Mineral oils are used in the making of the SAE 80w90. The gear oil is denser than 75w90 at cooler temperatures.

It requires more frequent oil adjustments and more maintenance as a result. Its production may be affected by its efficiency level being degraded at lower temperatures.

75w90 has a wide range of temperature preservation, which means it is a constant viscosity. In both hot and cold seasons, the 80w90 gear oil is more efficient than this gear oil.


There is a correlation between the thickness and density of gear oils. It means that gear oils with more density are denser.

The 80w90 gear oil has a density of 0.90, while the 75w90 gear oil has a density of approximately 0.86. 

The thicker gear oils offer better protection than thinner oils.

At lower temperatures, thicker oils get clumpy, which reduces efficiency. Even though the 75w90 gear oil is thinner, it still provides adequate protection in extreme weather conditions.


In terms of efficiency and composition, both 75w90 and 80w90 perform the same. The 75w90 gear oil has a special packaging that coats gears and prevents them from wearing out.

This gear oil is ideal for heavy-duty applications because it is reliable, non-foaming, and sleek. It is made to be resistant to extreme temperatures, while still lubricating.

Enhancing 80w90 with lubricating and anti-wear agents helps manage gear wear and tear. The heat control additives in this gear oil are difficult to get in other basic gear oils.

The 80w90 gear oil is ideal for heavy-duty use where other oils fail to perform.

Operating Temperature

75w90 is a para-synthetic, stable shear, and robust. It’s ideal to use in all types of vehicle drive applications with this gear oil.

The gear oil should be able to work under the temperature ranges. It can have temperatures as high as 350F.

80w90 synthetic gear oil is more versatile and can be used in both extreme environments.

The gear oil works perfectly in temperatures from -20F to 400F. 80w90 gear oil has a higher rating than 75w90, which is the most recommended gear oil.


When placed in extreme conditions, 75w90 and 80w90 gear oils behave differently than normal gear oils. 80w90 is the most preferred gear oil to use during the summer and winter.

This is because it is made to survive both extreme weather conditions.

In passenger vehicles, trucks, 4WDs, and light commercials, you can use 80w90 gear oil for manual gearboxes, agricultural equipment, transaxles, and transfer cases.

75w90 is ideal for higher temperatures and covers a wide range.

In high temperatures, premature wear and tear in your gear system can occur. It is recommended to use gear oil in heavy-duty manual transmissions.


We can’t compare 75w90 gear oils with 80w90 gear oils without talking about the price.

We want a product that will cut our overall cost and maintenance costs. In a wide range of temperatures, 75w90 has constant thickness and viscosity.

At very low temperatures and high temperatures, the oil becomes thinner and thicker. 75w90 gear oil is a little more expensive because of the dynamics.

It is a little more expensive than the 80w90 gear oil cost. 75w90 is worth it, even though it is more expensive.


Is It Possible to Use 80w90 Instead of 75w90?

It is possible to use 80w90 instead of 75w90. It’s a good idea to think about the conditions under which you will be using them.

80w90 gear oil has a higher viscosity. So, if you will experience extreme weather conditions, 80w90 is good.

Which Is Better?

Which is better between 75w90 and 80w90 depends on the gear oil you want to use.

The 75w90 is more stable in different temperatures than the 80w90 gear oil. It is ideal for preventing wear and tear in high temperatures.

80w90 works well in both high and low temperatures.

Since it’s mineral oil, it requires high maintenance. According to most experts, 75w90 gear oil is more efficient and gives you value.

Is It Possible To Mix 75w90 and 80w90?

You can mix 75w90 and 80w90 gear oils since they don’t differ too much. Your vehicle’s performance will not be affected by mixing the two.

Before you mix the two gear oils, it is advisable to consult your vehicle manufacturer’s manual.

Is It Bad to Mix Gear Oil?

Depending on the types of oil you want to mix, mixing gear oils will be different. It is possible to mix esters, PAOs, and Mineral oils. PAG should not be mixed with any other synthetic oils.

Some gum gels on the vehicle parts can be formed by mixing the wrong types of incompatible oils. It is recommended that you consult with your mechanic before you mix any gear oils.



Synthetic oils 80w90 and 75w90 are made from the same components and add the same Additives. Depending on their capabilities, the oils can be used in many different applications.

The difference between the gear oils can be seen in the 75w90 vs 80w90 comparison.

75w90 gear oil is more stable than the denser one, which provides better protection in extreme weather conditions.

It’s the most preferred gear oil for its protection in high temperatures. To purchase the 75w90 gear oil, you will have to add a few more coins.

Similar Posts