Transmission fluid and gear oil are two different liquids that belong to the category of lubricants. Depending on the application of these oils in equipment, their functionality can vary significantly. When we talk about transmission fluid VS gear oil, many factors play a role in differentiating these two components.
So, let’s get started!
Transmission Fluid or Gear Oil: Which is Better
To understand the difference between transmission fluid and gear oil, aspects such as viscosity, heat resistance, and pressure tolerance play an important role. So, let’s measure the effectiveness of both fluids based on these aspects.
1. Viscosity
Viscosity indicates the thickness of a liquid. Transmission fluid has low viscosity. It is fluid and lubricates the delicate parts of the car’s system. The viscosity of transmission fluid ranges between 0W/5 and 5W/10. Transmission fluid is fluid because it must continuously flow from the engine to other parts to transmit power.
When talking about the viscosity of transmission fluid compared to gear oil, of course, gear oil is thicker. The reason is the function of gear oil, which is to lubricate the entire gear train. It provides a damping effect that protects the gears from damage caused by shocks. The viscosity of gear oil is 5W/30.
2. Heat Resistance
Transmission fluid also acts as a coolant. It typically transfers heat, resulting from friction, from various internal parts. But, since it is thin and has a lower boiling point, heat can reduce the lifespan of the transmission fluid.
On the other hand, gear oil is capable of withstanding the temperature increase in the gearbox. Unlike transmission fluid, it does not evaporate when transferring heat from the gear train. Therefore, the thickness of gear oil increases its lifespan.
3. Pressure Tolerance
The operation of the gearbox involves significant pressure. Therefore, gear oil can easily withstand the highest pressure. Gear oil works well even with hypoid gears. The oil remains stable when the vehicle is running and operates consistently.
Transmission fluid, on the other hand, does not perform well under pressure. Instead, it is more effective at fulfilling other functions such as cleaning the channel between components and anti-foaming. When transmission fluid transfers power to the engine and other parts, airflow becomes vital. The anti-foam property of transmission fluid helps it combat airflow and function properly.
4. Gear Ratio
Gear oil is used in components with different gear ratios, such as manual transmissions and differentials, where gears are responsible for transferring power and torque to the wheels. Transmission fluid, on the other hand, is used in automatic transmissions that rely on a complex system of planetary gears and torque converters to vary gear ratios.
5. Maintenance Intervals
Gear oil is typically changed less frequently than transmission fluid. The drain intervals for manual transmission and differential oil can vary depending on manufacturer recommendations, but they are generally longer than the maintenance intervals for automatic transmission fluid.
6. Additives
Transmission fluids often contain additives that enhance friction properties, ensure better heat dissipation, and prevent foam formation. Gear oils typically contain additives that improve protection against extreme pressures, anti-wear properties, and corrosion resistance.
7. Equipment Compatibility
Gear oil is designed to withstand the high pressures and sliding friction that occur in gears. It contains specific additives to protect gear teeth and bearings from wear. Transmission fluid, on the other hand, is formulated to work with the clutches, bands, and valve bodies of an automatic transmission, where lubrication requirements are different.
The Verdict
You can use transmission fluid inside the gearbox, but it is not possible for an automatic transmission. Gear oil is far too thick for a transmission system and could block the entire functionality. In the worst case, use maintenance advice or contact a mechanic as soon as possible.
The golden rule for choosing the best transmission or gearbox oil is the one recommended for your vehicle. This way, you can play it safe with your car’s durability. So, choose the most suitable fluid for your vehicle now!