On many modern cars (both on passenger cars and off-road vehicles), you can more and more often find a CVT variator instead of the "classic" hydromechanical automatic transmissions. The fact is that variators, first of all, provide improved dynamic performance, are more economical, and this box is also considered the most comfortable.

Note, like any other unit, the variator also has its pros and cons, while many drivers prefer this particular type of automatic transmission. The serviceability and service life of the variator directly depends on the quality of service and compliance with the rules during operation.

In this article, we will look at how to change the CVT oil, when it needs to be done, how the oil in the CVT box is changed, and also what to look for when choosing lubricating fluids, etc.

Changing the oil in the variator: when to change and why

To begin with, changing the oil in the variator with your own hands is similar to the same procedure in the case of conventional automatic transmissions. However, it must be remembered that the oil change regulations and tolerances in relation to the transmission fluid itself for variators differ from hydromechanical automatic machines.

So, it is important to take into account that, in terms of its structure, the variator box differs from automatic transmission and manual transmission robots. This transmission is extremely sensitive to stress and oil quality. In fact, this means that such units are not designed for aggressive driving and harsh operating conditions.

Considering that even ordinary city trips in start-stop mode, slipping, sudden acceleration and stopping can already be considered difficult conditions, then it becomes clear that the box needs to be given special attention.

As for the oil, the transmission fluid tends to lose its properties over time, become contaminated with wear products, the additives are triggered, etc. In other words, even if the manufacturer claims that the box is maintenance-free, this does not mean that it really is.

As practice shows, experienced experts recommend changing the oil and oil filter in the CVT box, automatic transmission or robots with double clutch every 40-50 thousand km. mileage. The main reason is that all of these units have a valve body, which is a complex and expensive device. In this case, dirty oil can damage this element.

It is also worth noting that deterioration of properties and contamination have a destructive effect on other parts and components of the variator (belt, pulleys, cones, etc.). Taking into account the fact that it is difficult and very expensive to repair a variator, an oil change is a necessary and responsible procedure.

How to change oil in a CVT

So, having figured out the need for regular maintenance, let's look below how to change the oil in the variator box. It is not difficult to guess that in this case you can go in two ways:

• change the oil in the variator at the service station;
• change the oil in the variator box yourself;

As for the replacement methods, in certain cases they perform: a partial (incomplete) oil change in the box, a complete (hardware) replacement, a full replacement by the spill method.

• Partial fluid replacement in the variator involves renewing (refreshing) the oil. To put it simply, part of the grease is drained, after which you need to fill in exactly the same amount as was drained before, then correct the oil level in the variator.

To perform this procedure, you must first warm up the checkpoint by driving 10-15 km by car. Then you need to lift the car on a lift or drive it to the inspection pit. Next, a container for draining is substituted, the drain plug is unscrewed and the liquid is drained. The plug can now be tightened.

Then exactly the same liquid (manufacturer, properties, tolerances) is poured into the box as the one that was poured earlier. This approach will avoid the risks of mixing gear oils and possible consequences.

It is important to understand that in this way it is possible to update the fluid in the variator by only a third or a little more of the total fluid volume. In fact, the fresh fluid mixes with the old one, which is not drained from the unit through the plug.

To achieve a complete replacement, this procedure must be repeated at least 3-4 times (with an interval of 500-700 km). It is also recommended to double replace all automatic transmission filters (after the first approach and after the last), rinse the pan.

• A complete oil change in the variator is performed using a special installation. All replacement involves a displacement method, when the new fluid actually squeezes the old one out of the gearbox (replacement).

The device is connected to the radiator pipes of the variator cooling system, then fresh fluid is supplied under pressure, which displaces the mining. The device has observation windows so that you can control the pumping process, determining the degree of purification by the color of the liquid. The advantage is the most complete oil renewal in the variator.

Also, hardware replacement allows you to perform the procedure for flushing the variator before pumping oil into the box. Both ordinary oil and special flushing compounds can be used. Then a complete oil change is made in the variator on the apparatus.

Do-it-yourself oil change in the variator

To change the oil in a CVT without using special equipment, you will need to prepare:

• fresh oil in the proper volume (in advance, according to the manual, you need to find out what kind of lubricant to pour and how many liters to fill in the variator box on a particular car model).
• rags, clean rags, as well as drain containers, a set of tools;
• sump gasket and / or sealant, CVT oil filter.
• Before replacing the box, you need to warm it up well (drive about 10 km by car), then put the car on a flat surface in a garage with a viewing hole or lift it on a lift, drive onto an overpass, etc.
• Next, you need to turn off the engine, then wait about 60 minutes until all the oil drains back into the sump. We also recommend reading the article on how the variator is arranged and what types of variator boxes are. In this article, you will learn about the types, features and differences of CVT.
• Now you need to put a container under the drain plug, then the plug is unscrewed. You can also remove the dipstick from the box.
• After the liquid stops flowing out, you need to remove the pallet by unscrewing the corresponding bolts. Then the pallet is carefully removed, it is rinsed with a cleaner, chips are removed from the magnets, etc.
• Also, on many variators, it is advisable to remove the valve body by turning off the solenoids. We strongly recommend that you first study the information on removing the valve plate on a specific car model. The valve body can also be washed.
• After the elements have been removed and cleaned, you can begin to replace the internal variator filters. After replacing the valve body, put it in place, put in an external filter, mount a cleaned and dried pallet.
• After assembly, you need to check the alignment of the variator pulley with the valve body cylinder. To do this, you need to switch the selector in the cabin to different positions.
• If everything is in order, you can pour fresh fluid (oil) into the variator. To do this, you need to find the filling hole. At the end, it remains to check the level on the dipstick and correct it if necessary. Do not allow reduction and excess of the recommended oil level in the variator!

The article below is my IMHO and data provided by the largest manufacturers of CVT fluids. I am not responsible for the accuracy of the information they provide.
Everyone has the right to draw their own conclusions and decide which liquid to pour into their variator.

I was prompted to conduct this analysis by controversy regarding Subaru CVT fluids.
This article is focused on Subaru CVTs, however, it can be applied to CVTs of other automakers as well.

Clarifications.
690T - 690th CVT, which is aggregated with FA20DIT
690A - 690 CVT, which goes on outbacks, with FB engines
580A - 580th CVT, which is used on cars with FB engines.

1. Marketing Subaru.
Since 2009, Subaru began to massively introduce CVTs into its cars.
And there is a lot of information that the liquid is unique, no other is suitable, and so on blah blah blah.

2. Background.
A year ago, I began to figure out what kind of slurry is actually used, but I did not finish it, since in the case of the turbo Forester, the cost of 1 liter of the original is ~ 750r and there was neither time nor desire to bother with this issue.

Recently, I ran into a box problem, which was quickly resolved, and my discussion with Mikhail (who was changing a failed solenoid) on the subject of variator slurry prompted me to bring the issue to an end. Below I will tell you about what and how I did it.

3. Superficial googling.
Studying the experience of using third-party oils, I did not find any relationship between the use of native or third-party oil, with the number of CVT breakdowns.
Moreover, I noticed an interesting fact: for example, in the USA, many make the first oil change after 80-100 thousand miles! Below is the chemical analysis of the slurry after 82.9 tkm - its properties practically did not change, only there is a lot of dirt in it.
In the same Canada, Subaru dealers are selling original slurry for $ 60 per liter! As a result, people are actively using third-party fluids.

4. Gathering information.
From the very beginning I did not believe that a special formula had been developed for Subaru. It’s a very small automaker, so that one of the lubricant manufacturers would produce a unique slurry for it.
However, in order to have some kind of starting point, I decided to find a chemical analysis of the native slurry.
On the open spaces of the Russian Internet, I did not find anything, in connection with which I went to search the forums of other countries.
After a while, I found a chemical analysis of Subaru SOA748V0200, which is used in the USA as high torque for 690T CVTs (our analogue K0421Y0700).

Color difference between fresh and old SOA748V0200 liquid

Laboratory analysis of SOA748V0200 fresh liquid

Laboratory old liquid SOA748V0200

If you put everything in a table, it will look like this

As we can see, the physical properties of the liquid, such as viscosity, have not changed much.
The flash point of the old fluid has increased slightly.
Boron has become slightly less (one of the main functions of boron is the role of an ashless dispersant), therefore, its decrease is logical. The amount of Phosphorus and Calcium remained at the same level, and the increased elements, such as aluminum, iron, are explained by the wear of the mechanical part of the variator.
However, the most interesting thing is in the flash point, which is 204 ° С, which suggests that we have before us ... simple hydrocracking, without PAO and esters, with the most minimal additive package ...

The next step is to search for information about the characteristics of fluids from different manufacturers.
As a result, I brought all the information into a single table.

In this table:
1. The last 4 - dubious oils, Totachi and Mitasu levels.
For example, Amalie Universal Synthetic CVT Fluid.
It has a flash point of 190 ° C, but at the same time a pour point of -51 ° C, but this does not happen.
2. The eminent brands' slurries have a flash point higher than the original Subaru slurry, which indicates that they use PAO additives and such a slurry is higher than our own.

The closest performance to Subaru High Torque SOA748V0200 was Havoline® Fully Synthetic CVT Fluid.

By the way, notice an interesting feature: Subaru does not supply JXTG Nippon Oil & Energy slurry to the USA, which we have as K0421Y0700, but found another manufacturer in the USA who did not even bother to paint it red!
I don’t know what it’s connected with: perhaps the American FAS tapped Subaru's voice and forced her to order slurry from a local oil refining company, and perhaps it’s cheaper.

However, the Havoline website states that their Havoline® Fully Synthetic CVT Fluid is compatible with all Subaru CVT boxes:
Subaru Lineartronic CVTF (PN K0425Y0710)
Lineartronic CVTF II (SOA748V0200)
CV-30
High Torque CVTF
e-CVTF

Havoline is a pretty serious company in itself and understands perfectly well that if a US resident puts their product into his box and it breaks down, they will be dragged around the courts.

5. What about fluids for 580A and 690A?
Yes, everything is about the same. Here is a fluid test with a run of 60 thousand miles (96.540 km)

And if you look at the testing with even higher mileage?
For example, 123.250 miles (198.309 km!)

Let's summarize all the data in a summary table

Based on this table, we can conclude that the differences are:
- Calcium has a half times more.
- in the Bora athlete, 2.5 times less.
All. All other characteristics are identical.

From the changes in the characteristics:
- the flash point rises.

Flash point.
As we noticed in the comparison of turbine fluid, it increased during the aging of the oil.
And if we carry out the correlation of the flash point of the moisture, then we can estimate that most likely, in the database we had the same 204 ° С, that is, hydrocracking without PAO.

6. Results.
If we talk about the physical properties of the fluid, then Subaru fluids have a kinematic viscosity at 40 ° C higher than others.
This is probably a requirement that there is no chain slippage between the cones. Although ... after all, the viscosity at 100 ° C is the same as that of other liquids, or lower.
But most likely, this is just a lack of the cheapest oil.
By the way, mind you, the viscosity is identical to 0W-20 oils!

All this suggests that Subaru CVT fluid is the simplest, cheapest, and the use of any fluid of any brand manufacturer in most cases is of higher quality, but not lower.

If you really don't want to risk it at all, the owners of 580A / 690A CVTs can safely fill themselves with Subaru High Torque K0421Y0700, which is almost identical to K0425Y0711 (except for a slight difference in the additive package) and costs ~ 2 times cheaper.
Unless I strongly recommend not to mix with your old slurry, but by a complete replacement method.
In general, I am against partial replacement and consider partial replacement to be the same perversion than partial replacement in gearboxes or an engine.
However, I do not advise you to fill in K0415YA090, because there is a confirmed case where the use of this fluid led to the chain slipping in the cones. Unfortunately, I do not have a laboratory analysis of this liquid and I cannot say about the possible reasons.

7. To whom this topic is interesting and who would like to contribute to it, I will be grateful if you give it to laboratory analysis of the liquid:
K0421Y0700 (ready to provide fresh oil)
K0425Y0711
to find out their properties.
Probably, my division of oils by kinematic viscosity is wrong: if these oils are at the level of Eneos and Idemitsu, this will mean that they can be safely poured as a cheap analogue, including in the 690T variator (but this is not yet certain). To reduce the risk of problems, I recommend pouring only liquids into the 690T as analogues:
1. Havoline® Fully Synthetic CVT Fluid (closest to original, declared High Torque compatible)
2. Pentosin CVT 1
3. Redline Non-Slip CVT

The fact is that variators, first of all, provide improved dynamic performance, are more economical, and this box is also considered the most comfortable.

Note, like any other unit, the variator also has its pros and cons, while many drivers prefer this particular type of automatic transmission. The serviceability and service life of the variator directly depends on the quality of service and compliance with the rules during operation.

In this article, we will look at how to change the CVT oil, when it needs to be done, how the oil in the CVT box is changed, and also what to look for when choosing lubricating fluids, etc.

Read in this article

Changing the oil in the variator: when to change and why

To begin with, do it yourself changing the oil in the variator. However, it must be remembered that the oil change regulations and tolerances in relation to the transmission fluid itself for variators differ from hydromechanical automatic machines.

So, it is important to consider that in terms of its structure, the variator box differs from the automatic transmission and. This transmission is extremely sensitive to stress and oil quality. In fact, this means that such units are not designed for aggressive driving and harsh operating conditions.

Considering that even ordinary city trips in start-stop mode, slipping, sudden acceleration and stopping can already be considered difficult conditions, then it becomes clear that the box needs to be given special attention.

As for the oil, the transmission fluid tends to lose its properties over time, become contaminated with wear products, the additives are triggered, etc. In other words, even if the manufacturer claims that the box is maintenance-free, this does not mean that it really is.

As practice shows, experienced specialists recommend changing the oil and variator, automatic transmission or robots with double clutch every 40-50 thousand km. mileage. The main reason is that all of these units have, which is a complex and expensive device. In this case, dirty oil can damage this element.

It is also worth noting that deterioration of properties and contamination have a destructive effect on other parts and components of the variator (belt, pulleys, cones, etc.). Taking into account the fact that it is difficult and very expensive to repair a variator, an oil change is a necessary and responsible procedure.

How to change oil in a CVT

So, having figured out the need for regular maintenance, let's look below how to change the oil in the variator box. It is not difficult to guess that in this case you can go in two ways:

• change the oil in the variator at the service station;
• change the oil in the variator box yourself;

As for the replacement methods, in certain cases they perform: a partial (incomplete) oil change in the box, a complete (hardware) replacement, a full replacement by the spill method.

• Partial fluid replacement in the variator involves renewing (refreshing) the oil. To put it simply, part of the grease is drained, after which you need to fill in exactly the same amount as was drained before, then correct the oil level in the variator.

To perform this procedure, you must first warm up the checkpoint by driving 10-15 km by car. Then you need to lift the car on a lift or drive it to the inspection pit. Next, a container for draining is substituted, the drain plug is unscrewed and the liquid is drained. The plug can now be tightened.

Then exactly the same liquid (manufacturer, properties, tolerances) is poured into the box as the one that was poured earlier. This approach will avoid the risks of mixing gear oils and possible consequences.

It is important to understand that in this way it is possible to update the fluid in the variator by only a third or a little more of the total fluid volume. In fact, the fresh fluid mixes with the old one, which is not drained from the unit through the plug.

To achieve a complete replacement, this procedure must be repeated at least 3-4 times (with an interval of 500-700 km). It is also recommended to double replace all automatic transmission filters (after the first approach and after the last), rinse the pan.

• A complete oil change in the variator is performed using a special installation. All replacement involves a displacement method, when the new fluid actually squeezes the old one out of the gearbox (replacement).

The device is connected to the radiator pipes of the variator cooling system, then fresh fluid is supplied under pressure, which displaces the mining. The device has observation windows so that you can control the pumping process, determining the degree of purification by the color of the liquid. The advantage is the most complete oil renewal in the variator.

Also, hardware replacement allows performing the variator before pumping oil into the box. Both ordinary oil and special flushing compounds can be used. Then a complete oil change is made in the variator on the apparatus.

Do-it-yourself oil change in the variator

To change the oil in a CVT without using special equipment, you will need to prepare:

What is the result

As you can see, a car with a CVT is more comfortable compared to an automatic transmission and a fairly reliable solution in comparison with robots of the type. However, it is important to understand that the CVT is not designed for harsh conditions.

In practice, this means that a similar unit. At the same time, changing the oil and filters in the CVT variator is an important procedure that specialists in the repair of automatic transmissions strongly recommend to perform every 40-50 thousand km. mileage.

Read also

Operation of the CVT transmission: features of driving a car with a variator, maintenance of the variator. Helpful hints and tips.

Behind my shoulders are more than a hundred hand-picked engines and dozens of gearboxes. I also have an education in the field of engineering, and over the years I have learned to understand something worse than an academician. Reviews of motorists only confirm this.

This time I decided to talk about such a complex topic as CVT oil.In modern cars, a CVT box is installed, which is designed for such actions:

• Lubricates pulleys in a car;
• In this case, the differential is lubricated;
• Heat removal is also carried out;
• CVT lubricant is capable of maintaining normal gearbox temperatures.

CVT lubricant is made in much the same way as conventional motor lubrication. The essence is in the technology of stepwise hydrocracking.

• Extreme pressure performance. Provides the best protection of the automotive differential from the formation of chips and scuffing;
• Viscous. The grease thickens quickly at elevated temperatures.
• The lubricating oil in the variator box must be changed in time, since such oil quickly loses its properties.
• It is oxidized in operation, and the viscosity value also changes.

Basics of basics

The varied lubricant requirements of modern transmissions can only be met if, from an engineering point of view, the correct lubricant is used in the right amount under the permitted operating conditions in the transmission. Therefore, it is important to pay close attention to the relevant specifications and OEM approvals when repairing transmissions and changing transmission oils.

Transmission oil types

Due to its position as one of the leading developers and suppliers of lubricants in the automotive industry, FUCHS offers the largest range of gear oils. I would recommend purchasing this brand of oil.

Fluids for CVT and manual transmission

In modern manual transmissions, in addition to reducing wear, a lubricant performs a wide variety of tasks and influences ride comfort, as lubricant has a decisive influence on shift quality.

Axle drives require particularly high wear protection (AW) and extreme pressure properties (EP). This is only possible with highly concentrated sulfur additives, so classic oils are not suitable for clutch or timing.

In addition to high wear protection, axle drive oils must have good aging properties - consider this. Here, too, longer drain intervals and service life have to be achieved. With stricter pothole directives and regulations, CVT oils are becoming thicker and thicker to optimize drivetrain efficiency.

Automatic transmission fluids (ATF)

Important for the functionality of an automatic transmission is the coefficient of friction when opening and closing oiled plate clutches and brakes in automatic transmissions. This is exactly what the automatic transmission fluid needs to be fine-tuned for.

OEM specifications are decisive for the selection of automatic transmission oils.

Transmission oils for continuously variable transmissions (CVTF)

CVTF oils are very similar to ATF oils, but in addition to the ATF properties, they are specially formulated to take into account the frictional properties required for contact between metal friction parts (variator to chain / transmission chains). Because CVT transmissions typically use strong hydraulic pumps, CVTF lubricants must have particularly good foam and air release properties to prevent cavitation in the pump.

Dual Clutch Transmission Oils (DCTF)

Dual-clutch transmission fluids offer a compromise between high MTF performance and efficient ATF. In addition, the use of hydraulic pumps increases the requirement for stability.

CVT types

In addition to the CVTs described, below is a brief description of the main types used in passenger cars:

CVT belt type: also called "push-type" CVT or "Van Doorne".

The essence of the system

The belt is clamped in pulleys at a pressure of up to 4 tons and "pushed" through its pulleys. The compressive loads on the individual belt plates vary depending on the size of the engine, but they are quite high, starting at 120 Pascals for a small four-cylinder engine.

Chain type CVT: also called "tensioning". This CVT also uses clamping pulleys.

There are two main design advantages over a belt driven CVT:
Toroidal variator: This is quite complex. Imagine slipping the cone onto a potter's wheel and shaping the sides until they round off. Now place the two tori facing each other with a disc-shaped roller between them, touching both. You now have a toroidal variator.

Since it is not supported by belts or chains or clamping pulleys, the toroidal variator can transmit more torque. You won't find a toroidal variator in Russia - at least not now. It is only found on select Nissan vehicles sold in Japan.

While CVTs are cool and useful, there are a lot of reasons they don't fit into every car just yet:

• CVTs are much more complicated and more expensive to manufacture than they look in the pictures on the Internet. Generating high clamping forces that make them work is a challenge for hydraulic systems and lubricants. Parts must meet exact manufacturing and assembly specifications. Various royalties also increase costs for the automaker.
• Longevity (or rather its absence) - in fact, has become a big stumbling block. Belt slippage is the CVT's Achilles heel. If the belt slides even on a tiny pulley, then the transmission is destroyed.
• Some drivers just don't like them. Most people have no idea what kind of gearbox they have, but they usually expect the engine to make certain noises when running, and nothing else. A CVT car sounds almost like a motor boat. When you go downhill in it, the engine accelerates to high speed and begins to hum until you stop. And such a system doesn't have a gear shifter, so there won't be any changes in the engine tone you're used to with conventional transmissions. For this reason, owners of cars with CVTs often return theirs, thinking that the gearbox is slipping or something is broken.
• The increase in fuel economy is now in line with conventional powertrain performance.

Some automakers believe they can get more fuel efficient systems with a six or seven speed CVT.

The future of variators

However, the CVT has its loyal supporters. Nissan, for its part, is sticking to the Extroid CVT on its 245bhp Murano and plans to expand its use of the CVT fourfold over the next few years. For CVT car owners, Nissan North Russia product specialist Tony Pearson admits that manufacturers and dealers need to do more in developing CVT vehicles.

A couple of famous CVT oils

Mobil 1 Synthetic Gear Lube

Thanks in part to its synthetic base oils, 1 Synthetic Gear is the most stable over a wide temperature range. It stays fluid down to -50 degrees Celsius, but maintains its viscosity even in high-performance, high-performance differentials and rear axles, including limited slip differentials.

Additive Package 1 includes sulfur and phosphorus, but does not attack yellow metals such as copper cells. Suitable for all gear oil applications requiring API GL-5 grade. It extends drain intervals while reducing wear thanks to its phenomenal shear stability.

Pros:

• Extended drain intervals.
• Excellent cold fluidity.
• Mild EP additives.
• Excellent shear stability.

Minuses:

• Not suitable for GL-4 application.
• Not for the most extreme applications.

Red Line МТ-90

To improve synchronizer performance, manual transmissions require a low-slippery transmission oil. Red Line MT-90 is an API GL-4 synthetic gear lubricant that protects synchronizers and gears from wear. Its additive package also makes shifting easier at low temperatures.

Like all GL-4 lubricants, MT-90 contains no sulfur additives that can corrode and damage the copper components of the manual transmission. Its base stock is based on ether, so the oil is resistant to pressure surges at most operating temperatures.

Outcome

• There are about hundreds of different CVT oils on the market.
• CVTs are much more complicated and more expensive to manufacture than they look in the pictures on the Internet.
• Most people need help choosing an oil as they have no idea what kind of gearbox they have.
• The increase in fuel economy is currently in line with conventional powertrain performance. Improvements to the crawler gears have closed the gap.