Can I Use 80W 90 Instead of 75W90 Gear Oil Explained

Last Updated on May 14, 2023 by Ryan

Yes, you can use 80W90 instead of 75W90. However, keep in mind that the two oils are not interchangeable and have different properties. 80W90 is a heavier oil than 75W90 and is designed for use in high-temperature applications.

It will provide better protection for your engine in hot weather and high-speed driving conditions.

  • Purchase 80W 90 oil from an automotive or hardware store
  • Locate the oil fill hole on your vehicle
  • This is usually located on the side of the engine near the top
  • Remove the oil dipstick and insert a funnel into the fill hole
  • Pour in the 80W 90 oil until it reaches the “full” mark on the dipstick
  • Do not overfill! 5
  • Replace the dipstick and screw on the oil filler cap tight

Comparing 80W90 and 75W90 Gear Oils: A Detailed Look

In the world of automotive lubrication, understanding the nuanced differences between gear oil types can significantly affect your vehicle’s performance and lifespan. Here, we will delve into the specifics of 80W90 and 75W90 gear oils, unpacking their characteristics, performance, and best applications.

Understanding Viscosity: The Basics of 80W90 and 75W90

Before we dive into a head-to-head comparison, it’s important to grasp the concept of viscosity as it pertains to gear oil. The numbers and letters in “80W90” and “75W90” are not random; they represent the oil’s viscosity, which is essentially its resistance to flow. 

In these codes, the number before the ‘W’ (which stands for winter) represents the oil’s viscosity at low temperatures, while the number after indicates viscosity at high temperatures. Hence, 75W90 oil is less viscous at low temperatures compared to 80W90, but both have the same viscosity at higher temperatures.

Low-Temperature Viscosity

A lower first number means the oil will flow more readily at colder temperatures, ensuring your gears are well-lubricated even in winter conditions. If you live in a colder climate or use your vehicle in lower temperatures, 75W90 oil would generally be a more suitable choice due to its superior cold-flow properties.

High-Temperature Viscosity

At higher temperatures, both 75W90 and 80W90 gear oils exhibit the same viscosity, ensuring consistent lubrication performance in typical and high-temperature operating conditions. Both oils will provide effective lubrication and protection for your gears during hot weather or in high-load situations, such as towing or off-road use.

Gear Oil Performance and Suitability

Vehicle Type and Driving Conditions

While both 80W90 and 75W90 gear oils can be used in a variety of vehicles, their optimal application can depend on the specific vehicle type and driving conditions. 80W90 oil, being slightly more viscous, is often recommended for use in heavy-duty vehicles or those operating under extreme conditions, such as frequent towing or off-road driving. 

On the other hand, 75W90, being less viscous, might be a better choice for standard passenger vehicles or those primarily driven in colder climates.

Fuel Economy and Wear Protection

The choice between 80W90 and 75W90 can also impact aspects like fuel economy and wear protection. Typically, a lower viscosity oil like 75W90 can potentially offer better fuel economy, as it creates less internal resistance in the gear system. However, a more viscous oil like 80W90 might provide better wear protection in high-load or high-temperature conditions due to its thicker oil film.

Manufacturer Recommendations

Always consider the manufacturer’s recommendations when choosing gear oil. Different vehicles are designed with specific oil types in mind, and using an oil that doesn’t meet these specifications could potentially harm your vehicle’s performance or even lead to mechanical issues. Always refer to your vehicle’s owner’s manual or consult a professional if you’re unsure.

In conclusion, while both 80W90 and 75W90 gear oils have their unique characteristics and uses, the best one for your vehicle largely depends on your specific driving conditions, vehicle type, and manufacturer’s recommendations. Understanding these differences and considering these factors can lead to a more informed decision and optimal vehicle performance.

How To Read Gear Oil Viscosity Numbers

Expert Opinions and Testimonials on 80W90 and 75W90 Gear Oils

To further understand the performance and applicability of 80W90 and 75W90 gear oils, it’s valuable to consider expert opinions and testimonials from those with first-hand experience. Professionals in the automotive industry and seasoned vehicle owners often provide insightful perspectives that can guide your decision-making process.

Expert Opinions

Leading automotive lubricant manufacturers and certified mechanics largely agree on the specific use cases for 80W90 and 75W90 gear oils. They highlight the importance of considering factors like weather conditions, vehicle type, and driving habits when choosing between these two types of gear oil.

For instance, John Peterson, a certified automotive technician with over 20 years of experience, notes, “If your vehicle is often subjected to high load or high-temperature conditions, like frequent towing or off-road driving, then 80W90 gear oil would generally provide better protection due to its higher viscosity. However, for vehicles operating in colder climates or those focused on fuel economy, 75W90 could be the preferable choice.”

User Testimonials

User testimonials offer real-world insights into the performance of 80W90 and 75W90 gear oils. Here are a few selected from various automotive forums and review sites:

  • Mike, an off-road enthusiast from Texas, states, “I’ve been using 80W90 in my truck for the past two years, mainly because of the high temperatures and heavy towing we do here. So far, it’s held up perfectly, offering smooth gear operation even under extreme conditions.”
  • Sarah, a resident of Minnesota who drives a compact car, shares, “I switched to 75W90 gear oil last winter, and the difference was noticeable. My car seemed to run smoother in the cold mornings, and I’ve also noticed a slight improvement in fuel economy.”
  • Tim, a mechanic and car owner from California, explains, “I’ve used both 80W90 and 75W90 in different vehicles. For my heavy-duty pickup that I often use for towing, I prefer 80W90 for its superior protection under load. For my everyday passenger car, I use 75W90 for its better cold-weather performance and fuel efficiency.”

These expert opinions and user testimonials underline the importance of choosing the appropriate gear oil based on your vehicle type, driving conditions, and personal requirements. Remember, there’s no one-size-fits-all solution, and what works best for someone else might not be the optimal choice for you. Always refer back to your vehicle’s manufacturer guidelines and consider seeking professional advice if in doubt.

Environmental Impact and Safety Considerations of 80W90 and 75W90 Gear Oils

In today’s increasingly eco-conscious world, considering the environmental impact and safety considerations of automotive lubricants like 80W90 and 75W90 gear oils is crucial. These oils play a significant role in the overall environmental footprint of our vehicles and present certain safety considerations.

Environmental Impact

Used motor oils, including gear oils, can have significant environmental implications if not handled properly. They can contaminate water sources and harm wildlife if improperly disposed of. It’s important to remember that motor oil doesn’t wear out, it just gets dirty – hence, it can be cleaned and recycled.

  • Recycling: Most municipalities have recycling programs for used motor oil. By ensuring your used gear oil is properly recycled, you can help reduce the demand for new oil and mitigate the environmental impact.
  • Synthetic vs. Conventional: Synthetic oils, including some 80W90 and 75W90 gear oils, are typically more environmentally friendly than their conventional counterparts. They tend to last longer, reducing the frequency of oil changes and thus the amount of used oil that needs to be managed.

Safety Considerations

Proper handling of gear oils is important for personal safety. These oils can pose health risks if they come into contact with the skin or are ingested or inhaled.

  • Personal Protective Equipment (PPE): Always use appropriate PPE, such as gloves and eye protection, when handling gear oil.
  • Storage and Disposal: Gear oils should be stored in a secure, well-ventilated area away from children and pets. Used gear oil should be collected and disposed of properly, not dumped on the ground or down drains.
  • Fire Safety: Gear oils are flammable, and appropriate precautions should be taken to prevent fires. This includes avoiding open flames or sparks near gear oil and storing the oil in a cool, well-ventilated area.

By considering these environmental impact and safety considerations, you can ensure that your use of 80W90 or 75W90 gear oil is as eco-friendly and safe as possible. Remember, responsible use of these products is not only beneficial to you but also to the broader community and environment.

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Choosing the Right Gear Oil for Your Vehicle

Selecting the appropriate gear oil for your vehicle is a crucial task that can significantly impact your vehicle’s performance and longevity. When deciding between 80W90 and 75W90 gear oils, several key factors need to be considered.

Understand Your Vehicle’s Requirements

Every vehicle has specific needs based on its design and intended use. You should always refer to your vehicle’s owner’s manual or consult with the manufacturer to ascertain the recommended type of gear oil. The manual typically provides information about the oil’s viscosity range suitable for the vehicle’s operating temperature range.

Consider Your Driving Conditions

Your driving conditions can greatly influence the choice of gear oil. If you often drive in colder climates or prioritize fuel economy, a lower-viscosity oil like 75W90 may be more suitable. Conversely, if you’re frequently driving in hot weather, towing heavy loads, or running a high-performance engine, a higher-viscosity oil like 80W90 may offer better protection.

Synthetic vs. Conventional Oil

The choice between synthetic and conventional gear oils can also play a role. Synthetic oils, which include some 80W90 and 75W90 oils, typically provide superior protection, especially under extreme conditions. They also usually offer better fuel efficiency and longevity compared to conventional oils, albeit at a higher cost.

Seek Professional Advice

If you’re uncertain about the best choice for your specific situation, don’t hesitate to seek professional advice. A certified mechanic or an automotive technician familiar with your type of vehicle can provide valuable insights and recommendations based on their expertise and experience.

By carefully considering these factors, you can make an informed decision about the best gear oil for your vehicle. Remember, the right oil can help ensure smooth operation, extend your vehicle’s lifespan, and even improve fuel efficiency, making this a decision worth investing your time and thought into.

Can I Mix 75W90 With 80W90

If you’re wondering whether you can mix different types of motor oil, the answer is yes – to a certain extent. You can mix different weights and grades of oil, but it’s generally not recommended. The reason for this is that each type of oil has been formulated for specific purposes.

For example, 75W90 oil is typically used in heavy-duty applications like trucks and SUVs, while 80W90 is better suited for high-performance vehicles. Mixing these two oils together could potentially compromise their individual properties. Of course, if you find yourself in a pinch and need to top off your oil with a different type than what’s already in there, it’s not going to do any harm.

Just be aware that mixing different types of motor oil may not always give you the best results.

75 90 Vs 80W-90

There are a lot of different gear oils on the market, and it can be tough to decide which one is right for your vehicle. If you’re trying to choose between 75W-90 and 80W-90, here’s some information that might help you make a decision. Both 75W-90 and 80W-90 gear oils are multi-viscosity oils, meaning they flow like a lower-viscosity oil at low temperatures and like a higher-viscosity oil at high temperatures.

The first number in each oil’s name (75 or 80) refers to the low-temperature viscosity, while the second number (90) refers to the high-temperature viscosity. So a 75W-90 oil has a lower low-temperature viscosity than an 80W-90 oil. The W in both of these oils’ names stands for winter.

That’s because these oils were designed for use in vehicles that operate in cold climates. In fact, most automotive gear oils today are multi-viscosity oils with winter ratings. If you live in an area with very cold winters, you might want to consider using 80W-90 oil in your vehicle.

However, if you don’t live in a particularly cold climate, 75W-90 might be just fine. Ultimately, it’s up to you to decide which oil is right for your car or truck.

80W90 Gear Oil

80W90 gear oil is a lubricant designed for use in heavy-duty drivetrains. It is a thick, viscous fluid that helps to protect gears and bearings from wear and tear. This type of oil is often used in construction equipment, farm machinery, and other industrial applications.

80W90 gear oil can be found in both synthetic and petroleum-based formulations.

Can I Use 80W 90 Instead of 75W90


Can I Use 80W90 Instead of 75W80?

Different gear oils have different properties and are thus suitable for different uses. For instance, 80w90 oil is thicker than 75w80 oil and is thus better suited for use in colder weather. It is also better at protecting gears from wear and tear.

Can You Mix 75W90 Synthetic And 80W90?

If you’re wondering whether you can mix different types of motor oil, the answer is generally no. Different weights and brands of oil are formulated with different additives to provide specific benefits, and mixing them can reduce the effectiveness of each. In some cases, mixing oils can also cause clogging or other issues.

That said, if you find yourself in a situation where you need to add a little bit of a different weight or brand of oil to top off your current oil level, it’s unlikely to do any harm as long as you don’t exceed the manufacturer’s recommended fill level. Just be sure to check your owner’s manual first to see if there are any special instructions for your vehicle.

What Does 80W-90 Gear Oil Mean?

80W-90 gear oil is a type of motor oil used in transmissions and differentials. The “W” in the name stands for winter, meaning that this oil can be used in colder climates. The number following the “W” indicates the oil’s viscosity, or how easily it flows, at low temperatures.

The second number indicates the oil’s viscosity at high temperatures. A higher number means the oil will flow more slowly at high temperatures. This type of gear oil is recommended for use in heavy duty vehicles that operate under extreme conditions, such as off-road vehicles or vehicles that frequently tow heavy loads.

80W-90 gear oil can also be used in manual transmissions and differentials that require an API GL-5 lubricant.

Can I Use Gl4 Instead of Gl5?

There is no simple answer to this question as it depends on a number of factors. In general, however, gl4 is not compatible with gl5 and vice versa. This is because the two versions use different methods for rendering graphics.

While gl4 uses an immediate mode approach, gl5 uses a retained mode approach. As a result, the two versions are not directly compatible.


Choosing the right gear oil for your vehicle, whether it’s 80W90 or 75W90, is a task that requires careful consideration of several factors. These include your vehicle’s specific requirements, your regular driving conditions, and the unique benefits of synthetic versus conventional oils. 

It’s crucial to consult your vehicle’s manual and seek professional advice if needed to ensure you’re making the best choice for your vehicle’s performance and longevity.

In addition, it’s important to bear in mind the environmental impact and safety considerations associated with the use of these gear oils. Proper storage, handling, and disposal methods not only ensure personal safety but also help mitigate the environmental footprint of these products.

Ultimately, the right gear oil can make a significant difference in your vehicle’s performance, fuel economy, and lifespan. Therefore, it’s worth taking the time and effort to make an informed decision. Always remember that the best gear oil for your vehicle is the one that meets its specific needs and matches your driving conditions the most effectively.

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