Owners of gasoline or diesel cars will be all too aware of the several kinds of critical fluid that the car needs — engine oil, coolant, power steering fluid, brake fluid, and transmission fluid. The last item on that list is going to be the focus of today’s article. We’ll be answering a core question that many people wonder about: do Teslas have transmission fluid? If so, is it serviceable?
Let’s start at the very beginning by first getting to grips with transmission fluid, what it is and does, and then look at whether or not Teslas have it.
What is Transmission Fluid?
Many people tend to think of transmission fluid as primarily a lubricant in the way that engine oil is primarily a lubricant for the many moving parts of an internal combustion engine. That’s not entirely wrong, but it’s also not the whole truth. The fact is that transmission fluid serves as a lubricant, a hydraulic fluid for gear shifting, a coolant and an oil for the transmission.
Transmission fluid is typically a rich dark red color when it is purchased new. In the same way that we can check the engine oil by removing a dipstick in the engine bay, we can do the same thing for the transmission fluid. The fluid also loses its rich color and picks up a number of contaminants as it operates. After about 30,000 to 60,000 miles, depending on your OEM, you’ll have to change the transmission fluid.
Do Teslas Have Transmission Fluid? Do Any EVs?
One thing people have wondered about when it comes to Teslas and other EVs is how different they are to the internal combustion engine cars that for generations we have become familiar with and understand all too well. Most of us can imagine that they don’t have engine oil, since there is no engine. They instead use various greases to lubricate and cool the parts that need it, but of course it’s far fewer than with regular gasoline or diesel cars.
What about transmission fluid? Starting with Tesla, the broad and simple answer is that no, they don’t have transmission fluid as we really understand. There is only one exception to that rule, which is the Tesla Model S, which we will cover more below. Other Tesla models do use lubricating fluids in their gearbox/differential, but this cannot be understood as transmission fluid in any conventional sense. We’ll cover more on what fluids do exist in the Tesla gearbox/differential in the next section.
Tesla Model S
Let’s return to the Tesla that does apparently have transmission fluid. What fluid is it? Why is it there? Does it ever need changing? First of all, the transmission fluid that you’ll find in the Model S is Dexron VI (Dexron 6) Automatic Transmission Fluid. It may surprise some readers that Tesla doesn’t require some proprietary fluid to be used that you can only purchase from a Tesla service center or from the Tesla online shop at some hugely inflated price. Dexron VI from ACDelco is commercially available, even on sites like Amazon where you can pick up a quart bottle for about $10 or thereabouts.
The Tesla Model S requires different amounts depending on what drive units are in the vehicle. The car needs:
- About 1.5 quarts (1.4 liters) on the rear large drive unit.
- 2.4 quarts (2.25 liters) on the rear small drive unit.
- 1.8 quarts (1.75 liters) on the front small drive unit.
For Tesla Model S drivers, especially for models from 2012 to 2016, the fluid has to be switched out once after 12,500 miles (estimated for 1 year) and then again in years 5 and 9. We will cover more about the servicing of Tesla transmission and gearbox fluid further below. It starts to get very interesting when you move onto the more modern units and other Tesla models and their gearbox fluid.
What Fluids Does a Tesla Gearbox Contain? When Should They Be Changed?
As we mention further above the Tesla Model S uses Dexron VI automatic transmission fluid from ACDelco. It’s fairly inexpensive, with each change lasting several years after the first service is carried out.
Is it only the Model S, then, that receives transmission fluid? In fact, no it isn’t. Other Teslas, including the Model 3, X and others, do contain a special lubricating fluid in its reduction gearbox, but on the newest Tesla models, this fluid is now supposed to be maintenance free.
The above-mentioned guidance on the first change coming after 12,500 miles and then after years 5 and 9 has since been removed from later models and it’s now considered to be “maintenance free,” but the fact is that they may still need changing after 100,000 to 150,000 miles.
Changing this transmission fluid in your Tesla gearbox, however, is not as easy as an oil change on a regular car, nor as easy as adding more coolant or windshield washer fluid. You don’t just pour fluid into a cap and be done with it. Tesla has taken an approach similar to iPhones when it comes to fluid maintenance, and that is that most fluids, including the limited amount of oil that parts might need, are sealed and are not supposed to be accessed outside of a Tesla service center.
Infrequency of Gearbox Fluid Change
Why is there so much mystery surrounding the changing of gearbox fluid in Teslas? Why does there appear to be some big secret about it? Why has Tesla removed any recommendations regarding these fluid changes from their manuals? The idea from Tesla, and understood by many Tesla owners, is that when the company doesn’t recommend something, there’s no need to worry about it. If they haven’t told you when to look out for transmission fluid issues, then you don’t need to ever worry about it until you see the dashboard warning (see next section for more).
The Tesla models use the gearbox fluid as a way to lubricate the limited number of moving parts in the gearbox, but in the absence of multiple gear ratios, and in the absence of the heat that is generated by a typical internal combustion engine, the fluid lasts so much longer. It is not bombarded with fumes nor contaminated and corrupted in the same way, and so can last 100,000-150,000 miles, or what Tesla may deem “forever.”
Next, however, we come to those times when you get a warning about your gearbox fluid.
Why Does My Tesla Get a “Gearbox Fluid Service Recommended” Warning?
If there is a problem with the gearbox fluid, then your Tesla will warn you about it. The warning says “Gearbox Fluid Service Recommended.” This just means you have to book the car into a Tesla service center and have them check and possibly replace the gearbox fluid.
The current status in newer Tesla models is that the gearbox fluid is not part of regular fluid maintenance unlike other fluids such as coolant and brake fluid. The warning is in place for when the unexpected happens and a service is required. If you don’t see the warning, then you don’t need to worry about the gearbox fluid.
Conclusion: Teslas and Their “Transmission Fluid”
As it turns out, the answer as to whether Teslas have transmission fluid is a little more philosophical than we thought. There is fluid in the transmission, and for the Model S cars it was Dexron VI, and on other models a generic lubricant that they refer to as gearbox fluid. The function of this fluid is not as diverse as transmission fluid, which means that to some there is no “transmission fluid.” To others, however, fluid in the transmission, regardless of its overall function or serviceability, is still transmission fluid.
It doesn’t need changing anything like as often as transmission fluid, and doesn’t get contaminated in the same way. There’s also no dipstick for it. In our view, what Tesla have done is they have evolved the concept of transmission fluid into something else. While older Model S cars used a more literal transmission fluid, the newer Teslas are all using something a bit different, “Gearbox Fluid.”