75w90 vs 75w140 Gear Oil

75w90 vs 75w140 Gear Oil
75w90 vs 75w140 Gear Oil

There’s a lot of options in terms of gear oil in the market. Well, when every manufacturer claims that they own the best one, it is obvious to grow some suspicion and also compatibility checks are needed. This calls for a comparison of your desired products which led us to these two.

75w90 vs 75w140 Table

Gear oil doesn’t have any substitute but what they have is tons of manufacturers producing them. These two chosen products and their wide use have made them an imminent member of the gear oil industry and customers grew an acute interest in their difference. We have prepared a table comparing these two popular products.

Known as Gear 300 75w90

Known as Red line 75w140

Made by Motul

Made by Red Line

100% synthetic

100% synthetic

Viscosity indexing 222

Viscosity indexing 191

Flash point measured 200°C

Flash point measured 220°C

Good performance in all season

All season applicable

Ideal for load carrying, heavy duty and racing vehicles.

Good fit for light trucks, ford, mustang and jeeps.

Tremendous fuel efficiency

Generous fuel optimization

Meets the GL-5 requirements

GL-5 requirements exceed

Absorbs pressure like none. Anti-corrosion and industry leading resistance. Overall very compact product

Sustainable against friction, guaranteed protection against corrosion in extreme conditions. In short, a modern product that is utterly reliable.

75w140 Gear oil

When you choose a gear oil, you are choosing it depending on 3 things. The viscosity of the oil, its additives and the base oil type varies according to your working conditions. The one we are reviewing today is a perfect example of ideal gear oil.

This product here won the trust of the customers with its superb reliability. With compatibility, an important thing is the additives that come with the oil. Gear oils don’t just ease the parts, it has some other roles to play like stopping oxidation, corrosion and at the same time carry weights.

Being fully synthetic in nature it does the lubrication part with comfort. One of the most advanced additives in the oil is that this oil has friction modification within itself. High viscosity partnering with stability and thickness is destined to give you a better experience. Let’s have a look at their attributes and some features that come along:

  • Contains a 100% synthetic formula that offers smooth lubrication in different circumstances.
  • Friction is always kept under control as the oil comes with a friction modifier.
  • Being so high in viscosity, the oil is comfortable delivering thickness as per the temperature demand.
  • Superior result in terms of reducing oxidation and eliminating corrosion.
  • Exceeds the GL-5 requirement and have earned multiple appreciations.
  • Wearing out is never an issue with this oil. Moreover, it assists to ensure additional mileage.
  • Overall efficiency gets a boost thanks to the magnificent engineering behind the oil.

Our observation

Considering the fact that both of the oils are the same room temp, the 140 ones are surely thicker in operation. One thing you do have to bear in mind that the thickness of the oil is not always the fact. To lubricate the gears, they must have fluidity. Both of the gear oils have excellent fluidity. But if I had to choose an oil for heavy-duty use, I would go for the later one. Here is another comparison you might be interested in 75w90 vs 80w90.

What is the best 75w140 synthetic gear oil?

This is a tough question to answer. The very best companies in the auto industry take part in making gear oils. Choosing one is certainly a difficult task. However, The Valvoline SynPower caught my eyes in recent times. They are built with superior qualities and offer top-of-the-range amenities.

Can I use 80w90 instead of 75w140?

Yes, it can be used interchangeably. However, if your vehicle is for heavy jobs like towing then you are better off with the 140 as it is fully synthetic. Other than that, it will work just fine on both gear oils. Synthetic gear oils performed better than minerals but that comes with a slightly higher cost.

What’s thicker 75w90 or 80w90?

80w90 is thicker than 75w90. In moderate conditions many vehicles may produce a whining sound and a relatively thicker gear oil may put that at ease. However, you may find better results in extreme conditions using the first one.


It’s a never-ending debate about which one of the oils is better. Your choice of gear oil must be according to your usage and comfort. Both of the products we talked about are excellent in doing their job. You can purchase them without hesitation and trust me, you won’t regret it.

Frequently Asked Questions (FAQ)

75W-140 gear oil is a synthetic motor oil that is designed for use in high-performance applications. It is often used in racing vehicles and other vehicles that require extreme levels of protection from wear and tear. This type of motor oil can also be used in regular passenger cars and trucks, but it is not as common. Gear oils are typically heavier than engine oils, which helps them to provide better lubrication and protection against wear and tear.

If you have a car that is equipped with a manual transmission, then you will likely need to use 140 gear oil at some point. This type of oil is designed for use in high-performance applications where gear teeth are under constant stress. It can also be used in lower-performance vehicles that see occasional heavy use. If you are unsure about whether or not your car needs this type of oil, consult your owner’s manual or a qualified mechanic.
75W140 is a type of motor oil. It is a very thick oil and is used in heavy-duty applications such as trucks and buses. This oil is designed to protect the engine from wear and tear and to keep it running smoothly.



Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to Top