Best 75w140 Synthetic Gear Oil - Car of Steel

Best 75w140 Synthetic Gear Oil

Best 75w140 Synthetic Gear Oil

Gear is an essential part of a car’s engine. And this part controls the engine. Without gear, there would be a lot of problems and possible accidents.

But even with gear, there could be many unfortunate events if suddenly it didn’t function properly. Thus to make it work properly, one will need to keep the gearbox in top condition.

And to do that, you will certainly need the best synthetic gear oil. Therefore we came up with a list of the best 75w 140 synthetic gear oil in the market.

Top 5 best:

1. Lucas 10122 75/140 Synthetic Gear Oil – 1 Gallon:

Lucas 10122 75/140 Synthetic Gear Oil - 1 Gallon

A gearbox performs perfectly when it is treated correctly. These gearbox needs to be adequately lubricated so that it comes handy in tight situations.

If you are a car enthusiast, you already know that shifting gear perfectly is like an art. With every perfect gear shift, you would have the upper hand on your opponent while racing.

Even if own a manual car, then gear shifting properly is critical otherwise, your engine would turn off while driving. And this could be dangerous.

Lucas 1012275 is 75w140 full synthetic oil. This oil is one of the best gear oil in the market. They provide quality gear oil, and by using this gear oil, you could avoid a costly repair.

Because this oil protects the gearbox from wear and rust, therefore ensuring a healthy life span for the gearbox. This oil also lubricates the gear properly so that you can shift the gear smoothly.


1] Can deal with high temperature without breaking

2] Great lubricant

3] Great pricing


1] Not the best viscosity

2. Royal Purple ROY01301 MAX GEAR 75W140, 1 quart:

Royal Purple ROY01301 MAX GEAR 75W140, 1 quart

Royal purple is a renowned name in the oil industry. They are mainly famous for providing excellent quality engine oil.

Along with engine oils, royal purple also provides great quality gear oil. And royal purple max 75w140 gear is one there best gear oil.

This gear oil is specially designed for automotive front or rear differential, tucks, and manual transmissions.

Royal purple max gear protects from corrosion and extends the gear life. This gear oil is engineered to be tough, and it also provides max protection heavily loaded gears.

This gear oil is developed with a secret additive tech that almost outperforms most of the market’s gear oils.

Thus the gear performs quietly along with ultimate smoothness. Besides all of the cool features, these oils come in a wide range of viscosities.


1] Great additive provides

2] Best protection technology.

3] Ensures the utmost performance.


1] Slightly costly

3. Valvoline SynPower SAE 75W-140 Full Synthetic Gear Oil 1 QT:

Valvoline SynPower SAE 75W-140 Full Synthetic Gear Oil 1 QT

Valvoline syn power is the fully synthetic gear oil. It is one of the best gear oil in the market. This oil has a viscosity of 75w140. This oil stays stable at extreme temperatures because of the synpower.

This oil also comes with loads of beneficial additives which help to contain corrosion along with sufficient lubrication.

Valvoline synpower is premium gear oil with an affordable price range. This oil will provide ultimate performance and excellent protection thus marking the oil as best in its price category.

This oil will deliver in both cold and hot weather conditions. Its viscosity makes it perfect for most of the gears, but we would still recommend checking your car’s manual before using this oil.

We would recommend using this oil for conventional and non-synchronized manual transmission.


1] Contains beneficial additives

2] Affordable pricing

3] Great protection system


1] Not recommended for synchronized manual transmission.

4. Red Line 57915 75W140 GL-5 Gear Oil – 1 Gallon:

Red Line 57915 75W140 GL-5 Gear Oil - 1 Gallon

Redline 57915 is synthetic gear oil with API GL-5 along with the viscosity of 75W140. The Redline has been providing quality gear oil for a long time now.

This is one of their best synthetic gear oil. This oil comes with an advanced protection system, which helps to stop the corrosions of the gear. It also protects the synchronizer and the equipment from wear.

If you use this gear oil, you would not need any additional modifiers for most LSDs because it contains different friction modifiers for clutch-type stability. 

Keep in mind that this gear oil is not designed for most of the manual transmissions. In general, it is one of the best gear oil within an affordable price range.

If your vehicle gear transmission system requires gear oil the requirements of API GL-5 and API GL-6, then this gear oil is one of the best without a doubt.


1] Synthetic gear oil

2] Reasonable pricing

3] Will provide a smooth shift.


1] Not suitable for all manual transmission.

5. Amsoil Severe Gear SAE 75W140:

Amsoil Severe Gear SAE 75W140

Amsoil severs gear SAE 75w140 is specially developed gear oil for extreme duty applications. This gear oil provides impressive performance, and it is also better than any conventional gear oil.

Amsoil severe gear oil is synthetic base oil, and it is the best for most of the vehicles, it’s even best for racing cars and off-road vehicles.

This gear oil comes with enhanced and premium quality additives. This additive protects from wear and rust. This oil also helps to prevent micro welding. Thus ensuring smooth gear shifts.

This oil also doesn’t break at high temperatures because of the high viscosity level. This gear oil aces in cold and hot weather conditions.

According to some tests, this oil delivers 20% more in cold weather conditions than any other conventional oil.

 We can ensure that your gear would be well protected from most of the general problems, and this oil will undoubtedly improve the gear’s life span.

As it is premium gear oil thus this oil is a bit pricey. But this oil price is resembled and worth it.


1] Great rust and corrosion protection

2] Reasonable pricing

3] Great in cold and hot temperature condition


1] Not the best for light-duty vehicles.


How to Choose the Best synthetic gear oil:

Gear oil is essential for cars. You want to make sure you buy the best oil for the utmost performance. It would be best if you considered the following:

Types of gear oil:

There are mainly 3 types of gear oil, and they are:

1] Conventional gear oil

2] Synthetic gear oil

3] Full synthetic gear oil

The type of gear oil you should use ultimately depends on the type of your gearbox. But most gearbox can handle synthetic and full synthetic gear oil.


Viscosity is a huge factor when it comes to automobile oil. Thus choosing gear oil with the right consistency will ensure outstanding performance and smoothness.

We would recommend finding out the best oil with the right viscosity and would be a perfect fit. Check out the vehicle manual recommendation.


Additives provide enhanced performance and come with many features. There are many additives in the market, and most of the gear oils are enriched with beneficial additives.

Additives ensure better lubrication, temperature control, protection from rust, and wear. Thus we can say additives play a significant role, choose the gear oil wisely.


1] What’s thicker 75w90 or 75w140?

Answer: 75w140 will be thicker than 75w90 in the operating temperature.

2] Is thicker gear oil better?

Answer: Yes, thicker gear oil is better if you want high wear resistance, and you use a heavy load vehicle.

3] Is synthetic gear oil better?

Answer: Yes, synthetic gear oils are better than most of the conventional gear oils.


We have mentioned our tops picks. We hope that it was helpful and this made you easy to choose your desired gear oil.

If you purchase any of our top picks, then we can ensure you won’t regret it. They will ensure top-notch performance and pleasant experience.