Protecting bearings and gears from wear and scoring would be a priority whether you are heavy hauling, 4×4 off road driving, trailer towing, racing, or driving for commercial use. If you care about protecting your investment in the gear systems of your equipment or vehicles, choosing the absolute finest and highest performing lubricants would be an obvious priority. You have two choices when choosing a 75W140 gear oil: conventional petroleum based gear oils or synthetic based gear oils. In this blog post, we will lean our choice towards synthetics when deciding what is the best 75W140 synthetic gear oil.

Let’s have a quick refresher course on the difference between conventional petroleum based gear oils and synthetics.

Conventional Gear Oils versus Synthetic Gear Oils

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Conventional petroleum based gear oils have for many years served their purpose and have performed adequately in many applications. Conventional oils inherently have an uneven or irregular molecular structure, along with containing many impurities that can create unwanted issues and deposits. Because of the irregular molecular structure of conventional petroleum based oils, they tend to create more fluid friction.

Pinions and differential from gearbox.

Current OEM gear system designs demand a higher performing gear lube that unfortunately conventional petroleum based gear oils cannot provide. Synthetics are the way forward.

Friction will cause a rise in temperatures. This will lead to wasteful energy consumption and a slow degradation of the oil. Ultimately, this degradation leads to thermal breakdown, with the oil oxidizing over time. As the oil oxidizes, the inherent impurities begin to break down and cause deposits such as sludge and varnish. Oil starts to be consumed, and the viscosity begins to deteriorate into a lighter oil, or in some instances becomes thicker. This downward spiral will lead to unnecessary component wear and deposit buildup.

Conversely, synthetic base oils contain perfectly sized and even molecular structures. Additionally, there are no unwanted impurities. The uniform and pure nature of the molecular structure found in synthetic base oils deliver useful properties such as enhanced extreme temperature performance, superior wear protection, and outstanding fuel economy efficiency that conventional petroleum base oils simply cannot attain.

Monster truck over cars.

Monster trucks generate extreme torque and shock load that can only be effectively controlled by high performance synthetic EP gear oils like AMSOIL 75W140 SEVERE GEAR.

Two critical areas where synthetic based lubricants definitely outperform conventional petroleum base oils are in cold temperatures and hot temperatures. During tests conducted for cold temperatures, AMSOIL synthetic fluids outperformed conventional oils by 36% during cold starts. This is critical because 80% of wear occurs during dry cold starts. The fact that synthetics will reach critical components 36% faster than petroleum based oils means reduced component wear.

Dealing with hot temperatures is extremely critical today because car manufacturers are engineering power train systems differently, causing them to run much hotter than in the past. Because of these hot temperatures, petroleum base oils do not have the thermal stability that synthetics offers. Choosing a lubricant that can withstand extreme temperatures is critical. Unfortunately, conventional petroleum based lubricants are rather limited in terms of thermal stability. As temperatures rise to extreme levels, they tend to start to thin down and oxidize, exposing critical parts to wear.

Very muddy off road car.

Off road driving conditions demand a lot from transmissions and differentials. To withstand the abuse experienced by these gear systems, only a gear oil such as AMSOIL 75W140 SEVERE GEAR can deliver the correct protection.

Synthetic base oils are designed specifically to withstand extremely high temperatures, and because they do not have the inherent impurities that conventional lubricants have, they are far superior at resisting the formation of deposits and will keep power train systems five times cleaner than conventional lubricants.

Most in the know automotive enthusiasts, mechanics, engineers, and commercial fleet owners are all in agreement that synthetic lubricants are a better investment long term than conventional petroleum based oils. The benefits such as less wear, less friction, efficient performance, and longer life all contribute to saving money and reducing downtime.

Race car on track.

Open wheel race cars and fighter jets operate in extreme conditions. Synthetic lubricants are the only effective lubricating agents for these machines.

Let’s now move forward and discuss what makes AMSOIL 75W140 SEVERE GEAR the best 75W140 synthetic gear oil.

The Best 75W140 Synthetic Gear Oil

AMSOIL 75W140 SEVERE GEAR Synthetic Extreme Pressure (EP) Gear Lube is a state of the art gear lubricant custom designed for the absolute top of the line performance for any extreme duty application. This proprietary gear oil formulation contains a one of a kind blend of high viscosity, extremely shear stable, pure synthetic base stock oils. Added to this state of the art base stock combination is a robust volume of heavy duty additives.

It is critical that a gear oil be able to withstand any shearing action and maintain its viscosity for long periods of time if it is to guard against any metal to metal contact. The highly experienced AMSOIL chemists have engineered exclusive wear resistant additives that create an iron sulfide protective barrier on all gear surfaces the lubricant encounters. This tough wear resistant coating delivers amazing protection against scoring, pitting, and wear.

Logging truck being loaded.

A logging truck hauls extreme amounts of weight, thus placing tremendous demands on both the gear systems and the lubricants. A specialized extreme pressure gear oil such as AMSOIL 75W140 SEVERE GEAR thrives in these type of conditions.

Many gear systems encounter a phenomenon called thermal runaway. Thermal runaway happens because a lubricant is unable to control friction, which leads to an increase in heat during high stress operating conditions. Conventional petroleum gear lubricants struggle to control thermal runaway. AMSOIL 75W140 SEVERE GEAR lube was engineered to eliminate the potential of thermal runaway.

By minimizing and controlling friction, this synthetic EP gear oil will stop lubricant degradation and any potential parts damage. Ultimately, AMSOIL 75W140 SEVERE GEAR allows equipment to last longer, run cooler, and run better during extreme operating conditions.

Large yellow dump truck.

Mining and quarry dump trucks haul heavy loads and run with huge amounts of torque. To protect gears and bearings from wear, pitting, and scoring, use a thermally stable synthetic gear lube such as AMSOIL 75W140 SEVERE GEAR.

From a pure performance standpoint, AMSOIL 75W140 SEVERE GEAR is the best 75W140 synthetic gear oil because it delivers enhanced performance way beyond what petroleum based gear lubricants could deliver. This extreme pressure synthetic gear lubes is engineered to provide outstanding protection for bearings and gears. They can effectively reduce friction and lower operating temperatures within gear systems. Due to their molecular structure and negligible fluid friction, they effectively improve the efficiency of the operation of gear systems and will vastly extend their service life, component life, and lubricant life.

Handle Temperature Extremes with Synthetics

The fact is, synthetic lubricants were designed to perform admirably in both cold and hot temperature extremes. They were engineered to guard against high heat breakdown and designed to control and eliminate varnish, carbon, and acid formation. Synthetic base oils are inherently free of unwanted impurities such as wax and other unwanted byproducts. Because of their pure nature, they offer superior cold weather flowability and superior cold weather shifting, thus delivering better fuel economy.

Red Coca Cola truck.

Whether the temperature is cold or hot, only a 100% pure synthetic gear oil can effectively operate during extreme temperature conditions for long durations of time.

Superior Cold Weather Protection

Not all synthetic gear oils are created equally. During the ASTM D-2983, conducted by an independent testing facility, it showed that AMSOIL 75W140 SEVERE GEAR delivered 20% better cold weather protection than industry standards specify. In this same test, both Mobil 1 75W140 Gear Oil and Valvoline SynPower failed to meet the basic minimum industry standard requirements for cold weather protection. If you want the finest in cold weather protection for your gear systems, then the only choice is AMSOIL’s SEVERE GEAR 75W140 lubricant.

Versatile for Multi Use Applications

If you’re looking to minimize confusion and reduce the need for multiple gear oils, then AMSOIL 75W140 SEVERE GEAR Synthetic Extreme Pressure (EP) Gear Oil was engineered for a wide range of uses and applications. The tougher the situation and environment, the better SEVERE GEAR performs and protects. Here are some of the following severe applications where SEVERE GEAR will deliver the finest performance and protection available anywhere.

Red Mustang.

AMSOIL 75W140 SEVERE GEAR would be the best choice for the discerning muscle car enthusiast. Both the Mustang car owner and the car itself will appreciate the superior performance delivered by this gear lubricant.

It can be used in high temperature environments, cold temperature environments, rapid acceleration, constant stop and go driving, racing, hauling, towing, plowing, off road use, commercial use, steep hill driving, and many other situations.

It finds a home in the following types of heavy duty vehicles: turbo diesel pickups, delivery/utility vehicles, vans, SUVs, heavy duty trucks, race cars, motor homes, tractors, buses, 4x4s, tow trucks, etc.

AMSOIL 75W140 SEVERE GEAR can be recommended for use in manual transmissions, differentials, and other gear system applications that call for any of the next stated specifications: API GL-5, MIL-PRF-2105E, Mack GO-J, MT-1, Dana SHAES 234 (Formerly Eaton PS-037), or other GL-5 specifications from the car manufacturers such as Chrysler, GM, and Ford. It may also be used in axles that recommend an API GL-4 oil.

Black Jeep.

The 4×4 Jeep is the perfect vehicle for testing and proving the amazing versatility and performance that can be derived from AMSOIL’s SEVERE GEAR Synthetic Extreme Pressure Gear Oil.

AMSOIL 75W140 SEVERE GEAR offers the best 75W140 synthetic gear oil. It is a lubricant that is compatible with both petroleum and synthetic gear lubes. Though it is compatible with other gear oils, mixing AMSOIL gear lubes with other gear oils may reduce the lubricant’s service life and diminish any benefits that could be reaped if used as a standalone lubricant. AMSOIL will not recommend longer drain intervals when oils have been co-mingled and mixed.

Additionally, after market oil treatments other than those recommended by AMSOIL will not be recommended for use with AMSOIL gear lubes. AMSOIL 75W140 SEVERE GEAR Synthetic Extreme Pressure (EP) Gear Oils are compatible with most types of limited slip differentials. For those unique applications that demand an additional limited slip friction modifier, it is recommended to add AMSOIL Slip Lock.

Hymer mobile home.

Motor homes present a challenging environment for any lubricant when climbing hills during the summer or when traveling cross country. To keep gear systems running cool and at peak performance, use only synthetic lubricants.

AMSOIL SEVERE GEAR Features and Benefits

AMSOIL 75W140 SEVERE GEAR has been proven in real world conditions and through independent testing to be the best 75W140 synthetic gear oil due to its ability to reduce friction, lower operating temperatures, effectively minimize and control thermal runaway, improve fuel economy, offer superior cold weather operation and protection, guard against corrosion and rust, improve gear system efficiency and performance, and offer fast installation of gear oil with its exclusive flexible easy pack containers.

Black drag racing car.

Racing has always been the perfect test bed for lubricants. Without a doubt, synthetics will win the day over conventional oils. Use AMSOIL 75W140 SEVERE GEAR to handle torque, shock load, and deliver peak performance.