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Do Evs Have Transmission Fluid?

A mechanic pouring a transmission fluid in a car engine.

Contrary to popular belief, electric vehicles are in many ways easier and cheaper to maintain than internal combustion engine cars. Being equipped with the most advanced technology, it would be expected that the maintenance needs of electric cars are greater and more expensive, but the reality is that they require less time in the workshop, with less impact on the pocket that this entails.

Minimal Maintenance

The advantages derived from regenerative braking, the lower number of moving parts and mechanical components, as well as fewer fluids compared to a traditional vehicle, mean that an ecological car requires much less routine maintenance. However, much less is not the same as nothing, and, among others, the electrical system (battery, motor, and associated electronics) requires minimal scheduled maintenance. Let’s get started! 

The Cooling Effect

A car mechanic checking his car if it needs a cooland or transmission coolant.

The cooling and transmission fluids in electric cars are very special. We will tell you why. Electric vehicles do not use lubricants for their engines as conventional ones do. However, these cars do need lubrication elsewhere. They even require fluids that, although their main mission is not to lubricate, must have certain lubricating properties. 

This means that although electric vehicles use transmission fluids or coolants like conventional cars, those fluids have some substantial differences. The simple fact that they can come into contact with electrical cables or components through which electricity passes has a very important influence on their formation.

The Transmission

Even the transmission is fundamentally maintenance-free in most electric vehicles. By having a differential and a single single-speed gear reducer, the complexity of this type of transmission is much less than that of a typical multi-speed manual or automatic gearbox.

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Although it also uses transmission fluid to function without problems, in general, it will not be necessary to replace it during the useful life of the car. In fact, most manufacturers claim that the unit is sealed for life. However, please note that the transmission oil may need to be changed, so it is highly recommended that you refer to your car owner’s manual for recommended transmission oil change intervals.

Coolants and Fluids

Electric Vehicle Coolants and water tank.

What are electric vehicle coolants and transmission fluids like? Cooling fluids for electric vehicles come into contact with some particularly important components such as the battery. These are elements that work optimally in a very specific range of temperatures.

For this reason, refrigerants are so important in a vehicle with an electric motor. They are the ones in charge of extracting heat from the batteries so that they run smoothly. What’s more, these fluids can also cool both the electric motor and the power systems.

In this sense, the fluid must fulfill its refrigerant function, but it must also have certain essential characteristics so that electrical discharges that can cause a problem do not occur. On the other hand, there are transmission fluids for electric vehicles. These are the ones that, in addition, require certain lubricating properties to ensure the correct functioning of these systems.  

Characteristics of fluids for electric vehicles 

What does all this mean? That the essential characteristic of these products – taking energy at the point where it comes into contact with high temperatures to cool it- must be joined by others:

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Insulation: the product must be insulated, that is, it must not facilitate the passage of electricity or electrical discharge, which can cause damage to systems. This insulating capacity must be maintained over time, which means that it must not be affected by the presence of elements such as dust or humidity. To control this is the characteristics of the product’s dielectric properties, which are what will determine whether it is an insulator or not – electrical resistivity, charge transmission loss…

Cooling: these fluids for electric vehicles must have a significant cooling capacity. When operating at high speeds, high temperatures can occur in electrical systems and mechanical elements. That is why it is necessary that the products used have a solid capacity to conduct heat and store it. The thermal properties of the fluid are controlled at this point.

Lubrication: in addition to all this, the products that are in contact with the mechanical parts of the gearboxes and the reductions must be lubricants. The objective is none other than to facilitate the movement of the parts and reduce possible wear and tear that may occur. The characteristic properties of a normal oil are those that would apply here, as is the case with viscosity.

Stability: especially in the case of battery cooling liquid, it must have a high flash point and be very stable over time to protect these elements from possible fires.

Protect from corrosion: this is very important in vehicle power systems. The fluids must not attack the products that wrap and insulate the copper cables and, if they come into contact with them, they must not corrode this element.

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Conclusion

Close-up photo of a man changing his transmission fluid for his vehicle.

There are many characteristics that fluids must meet for vehicles with more hybrid and electric motors. This is the reason why new specific ranges have been created for them, both for light and heavy vehicles. Using the most suitable product for each vehicle is essential to take care of it. A reality that, as you have been able to verify, you must keep in mind even if your car mounts electric motors.