Transmission Fluid VS Gear Oil – The Inclusive Contradiction

Transmission and Gear oil are two different liquids that come in the category of lubricants. Based on the application of these oils in equipment, the functionality may diverge drastically. When we talk about transmission fluid VS gear oil, many factors play their role to differ these two components.

So let’s get started!

Transmission Fluid VS Gear Oil: Which one is better

To understand the difference between transmission fluid and gear oil, aspects like viscosity, heat resistance, and pressure tolerance play an important role. So, let’s measure the efficiency of both liquids based on these aspects.

1. The viscosity

The viscosity indicates how thick a liquid is. Transmission fluid has low viscosity. It’s thin and lubricates the fragile parts of the car system. The viscosity of transmission oil comes somewhere about 0W/5 to 5W/10. Transmission fluid is thin because it needs to flow constantly from the engine to the other parts to pass on the power.

When talking about the viscosity of transmission fluid vs gear oil, of course, gear oil is the thicker one. The reason for that is the function of gear oil to lubricate the entire gear train. It provides a cushioning effect that protects gears from being damaged from shocks. The viscosity of gear oil is 5W/30.

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2. Heat resistance

Transmission fluid performs as a coolant too. It generally transfers the heat, which is the result of friction, from various internal parts. But, since it’s thin and has a lower boiling point, the heat can decrease the life expectancy of transmission fluid.

Comparing transmission fluid VS gear oil
Heat Resistance of transmission fluid and gear oil. Source: Youtube

On the other hand, gear oil is capable of standing with the increasing temperature in the gearbox. Unlike transmission fluid, it doesn’t boil off whilst transferring the heat from the gear train. Therefore, the thickness of gear oil increases its period.

3. Pressure Bearing

The gearbox working includes a lot of pressure. Therefore, gear oil can bear the highest pressure easily. The gear oil performs well even with the hypoid gears. The oil remains stable when the vehicle is running and functions consistently.

The transmission fluid, on the other hand, doesn’t work well under pressure. Instead, it is better at performing some other functions like cleaning the channel between components and anti-foaming. As the transmission fluid transfers power to the engine and other parts, the airflow becomes vital. The anti-foaming property of transmission fluid helps it to warfare with the airflow and work well.

Is gear oil the same as transmission fluid: 

4. Gear ratio

Gear oil is used in components with different gear ratios, such as manual transmissions and differentials, where the gears are responsible for transferring power and torque to the wheels. Transmission fluid, in contrast, is used in automatic transmissions that rely on a complex system of planetary gears and torque converters to vary the gear ratios.

5. Service intervals

Gear oil is typically changed less frequently than transmission fluid. Manual transmission and differential gear oil change intervals can vary depending on the manufacturer’s recommendations, but they are generally longer than the service intervals for automatic transmission fluid.

6. Additives

Transmission fluids often contain additives that enhance frictional properties, provide better heat dissipation, and prevent foaming. Gear oils usually have additives that improve extreme pressure protection, anti-wear properties, and corrosion resistance.

7. Gear compatibility

Gear oil is designed to withstand the high pressures and sliding friction that occur in gear sets. It contains specific additives to protect the gear teeth and bearings from wear. Transmission fluid, on the other hand, is formulated to work with the clutch packs, bands, and valve bodies in an automatic transmission, where the lubrication requirements are different.

The Verdict

You can use transmission fluid inside the gearbox but the same isn’t possible for automatic transmission. Gear oil is way too much thick for a transmission system that it could jam the entire functionality. In the worst-case scenario, use the maintenance tips or contact the mechanic as soon as possible.

All about transmission fluid VS gear oil
Transmission fluid vs. gear oil- which is better for your vehicle. Source: Youtube

The golden rule for choosing the best liquid from transmission fluid VS gear oil is the one, which is recommended for your vehicle. This way you can play safe with the durability of your car. So, choose the most suitable liquid for your vehicle now!