Variable speed drive. This word has firmly entered the dictionary of motorists and for many it causes not only an unpleasant taste in the mouth, but also a strong desire to tap on the keyboard, expressing dissatisfaction with the very existence of CVTs in nature. Naturally, there is no smoke without fire. Continuously variable transmissions, despite their advantages, do have a whole bunch of problems. Let's look at the famous and common ones.
Today, CVTs can be found in the lineups of many major automakers. Officially, cars with continuously variable transmissions are sold in Kazakhstan by Toyota, Nissan, Renault, Mitsubishi, Subaru and Kia.
The Jatco CVTs receive the most criticism from motorists. They are equipped with Nissan, Renault and Mitsubishi cars. At the same time, you can find them both on small cars and on Nissan Murano with a 3.5-liter engine, for example.
Jatco
Regardless of the marking of the gearbox, all of them, from the old JF010E to the fairly modern JF015E, share one serious hereditary drawback - a weak pump with a pressure reducing valve. Jamming of the latter entails a lack of pressure, and this, in turn, leads to loss of contact between the cones and the belt and, accordingly, the appearance of scoring on the working surface. The cost of a new pump is 50 thousand tenge.
Jatco variator oil pump
JF010E (RE0F09A/B), JF011E (RE0F10A) . Both boxes are almost identical, but are designed for different cars. The first was installed on Nissan Altima (2007–2012), Murano (2002–2016) and Teana (2003–2016) with 3.5 liter engines.
Jatco JF010E
The second was offered on cars with engines up to 2.5 liters. In this list you can find Mitsubishi Lancer (2007-2009), ASX (2010-2017) and Outlander (2009-2014), as well as Nissan Juke (2011-2016), Qashqai (2006-2015) and X-Trail (2007-2015). 2015).
Jatco JF011E
This pair is considered to be quite reliable in comparison with its followers. The average resource ranges from 150 thousand to 200 thousand kilometers. Prices for used transmissions range from 150 thousand to 550 thousand tenge. In addition to the hereditary disease of the pressure reduction valve, which leads to the death of the belt and cones, the valve body can be called a weak point, but only under the condition that the car owner either often warmed the box or forgot about replacing the transmission fluid. The part is serviceable and must be washed, but in advanced cases the channels will not only be clogged with a suspension of dust from the clutches (which will also require replacement, the price of a complete set (forward and rev) is about 20 thousand tenge), but also worn out. Restoring a hydraulic unit, if you find craftsmen, can cost 160–250 thousand tenge, and buying a new one can cost over 400 thousand.
Also, CVTs do not like sudden acceleration from a standstill. In this case, the belt moves along a very small radius, which increases the risk of slipping. This harms both the belt itself, which costs 110–130 thousand tenge, and the cones.
Comparison of new and worn variator belt
If the JF010E or JF011E starts to get sick, then the cost of a high-quality CVT rebuild sometimes comes close to one million tenge.
JF015E (RE0F11A) is the first mass-produced Jatco variator with a planetary gear, which takes the load from the variator unit at low speeds. Its appearance eliminated the problem with sudden acceleration from a standstill and driving in traffic jams.
The model is found on many cars of the Renault-Nissan alliance with 1.6 liter engines. The list includes Nissan Juke and Qashqai, Renault Kaptur, Logan and Sandero Stepway. Recently, a similar box appeared on Lada Vesta and XRAY with Nissan HR16 under the hood.
Jatco JF015E
Unfortunately, the average resource of the JF015E is noticeably lower than that of the older JF010E, for example. Such boxes rarely travel more than 100 thousand kilometers, and the first problems may appear as early as 20 thousand. Today you can buy it secondhand for 140–480 thousand tenge.
The variator retained the hereditary problem with the pressure reduction valve sticking, and also acquired a number of its own sores. These include the input shaft bearing, which suffers from misalignment of the shaft itself under load. If the part is not replaced in time, then the body, or rather the broken seat, may also require attention.
The engineers also overlooked the structural weakness of the sun gear in the planetary gear. It breaks right along the weld seam - as a result, the car cannot move forward.
This is what the consequences of a structural weakness of the sun gear in a planetary gear look like. It broke right along the weld seam
It is also important to know that, unlike JF010E and JF011E, the valve body in the 15th box cannot be washed. If it gets clogged, you'll have to buy a new one. Its cost is from 350 thousand tenge.
JF016E, JF017E . Both of these boxes replaced the JF011E and JF010E, respectively. CVTs are similar in design, but when developing and producing new models, the company decided to use cheap components and more complex control systems. The average resource on more powerful engines is about 100,000 km.
Jatco JF017E
In general, the list of models on which this pair is used is similar: JF016E can be found under the hood of Mitsubishi Outlander, Nissan Pathfinder, Murano, X-Trail and Teana, as well as Renault Koleos with 2.5 engines. JF017E is equipped with cars with a 3.5-liter unit. The latter, by the way, has a version with a chain instead of a belt.
CVT chain
The weakest unit of the couple can be considered the hydraulic unit, which, among other things, is irreparable.
In its predecessors, changing the transmission gear ratio was controlled by a stepper electric motor. Then they decided to remove it, replacing it with solenoids, and such that it would not be possible to simply replace the failed one. Each of the valves requires individual calibration, otherwise the gearbox will not work correctly or the car will not go anywhere at all. A new hydraulic unit always comes with a disk on which the same settings are recorded. The part will cost approximately 295 thousand tenge.
Of course, it is not necessary to buy a new valve body. You can search for it in the “Spare parts” section on the Kolesa.kz portal. But... along with the part you need to purchase a control unit. Both parts must come from the same car.
Valve block from JF017E with adjustment disk
Additional options and modes
Most car models also have other transmission modes for certain driving conditions. This is a sport mode that provides better responsiveness to the gas pedal. This operating mode is intended for intensive driving, but the CVT changes gears slowly, thereby providing more traction as the revs rise.
Economy mode is the exact opposite of sports mode. The box adapts to the driver and the movement so that interaction with the engine is maximum and fuel consumption is minimal.
Also, some models have modes for difficult conditions. Here the transmission must provide maximum gear ratios on a pair of drive wheels.
Aisin
CVTs from the Japanese company Aisin are found on the Kazakh market in Toyota cars and hybrid versions of Lexus, including the Toyota Corolla, C-HR and RAV4 crossovers with a 2-liter engine.
Unlike Jatco CVTs, Aisin gearboxes do not have serious hereditary diseases, but they also do not like overheating and untimely maintenance. The worst effect on CVT performance is the prolonged combination of these two factors.
Burnt transmission fluid loses both its cooling and lubricating properties. This leads to wear of the parts, and the resulting metal shavings can damage the bearings on the primary and secondary shafts of the cones. The set costs about 85 thousand tenge.
On Aisin variators, problems with leakage of variator drive oil seals are occasionally encountered. There are known cases of the shaft being torn off from one of the clutch packs.
Towing
And this is also prohibited, just like skidding. For the box, both of these actions are very unsafe. You can take the car towed - the engine must be running. But even if there is no oil starvation, it is better not to risk it. The instructions on how to drive a CVT specifically state that towing is possible either with a rigid hitch or with a flexible hitch in neutral mode with the engine running. If the conditions are different, then it is better and cheaper to call a tow truck.
But don’t get carried away with towing other cars. This will lead to increased loads on the transmission system and increased, intense wear. Manufacturers and repair specialists only allow the transportation of trailers with a gross weight of up to 1 ton.
Subaru
Since 2009, Subaru has installed its own CVTs, collectively known as Lineartronic, on almost all cars in its lineup. For 11 years there were two types: TR690 and the modified TR580. Unlike many other CVT units, Subaru units use a chain instead of a belt.
Subaru Lineartronic
The first gearboxes are remembered for problems with oil supply pipes. They were too fragile, although they were made of metal. Now they have been replaced with plastic - this problem no longer bothers the owners.
The hydraulic unit may also break. It becomes clogged with small particles that eventually appear in the ATF. If you change the fluid infrequently, then you will have to shell out to replace the valve body, and that’s more than 420 thousand tenge just for the part.
Around 150 thousand kilometers the chain and cones will need to be replaced. The latter will cost almost 400 thousand tenge per pair. The chain itself costs about 200 thousand. Well, don’t forget about work: they can ask for about 60 thousand tenge.
A powerful spring is hidden under the cones of Subaru CVTs
A replacement CVT can also be found on the secondary market. Prices for TR690 are in the region of 300–420 thousand tenge, newer TR580 are much less common, but cost about the same.
As you can see, CVTs really have a lot of problems, including not the longest service life and safety margin, but some of them are caused not so much by the catastrophic unreliability of the design itself, but by errors in operation.
Most manufacturers require periodic replacement of the fluid in their CVTs, but automakers often forget about this and claim that the fluid is designed to last a lifetime! But in practice, the oil must be updated at least every 50,000–60,000 kilometers, and only original oil must be used. Replacement costs vary depending on the manufacturer of the box and the amount of fluid required. Together with new filters, you can expect an average of 50 thousand tenge.
When the variator starts to “kick”, alas, it is useless to change the oil. Usually jerking indicates significant wear of the elements and the need for repair. It is important not to delay your visit to the service and not to wait for expensive repairs, the cost of which, if original parts are used, can exceed a million tenge.
Lack of diagnostics
In order for the variator to last as long as possible, it is important to ensure that the electronics are in good condition. The main method of control is regular computer diagnostics. It is necessary to check the condition of the electronic control module board, speed sensors, stepper motor, and pressure solenoid valves. If errors are detected, corrective action should be taken immediately.
Some drivers avoid purchasing cars with continuously variable transmissions, not wanting to "bother." But when driving with a CVT, it’s worth learning some of the nuances of its operation.
Reverse
It is traditionally denoted by the symbol "R". The design of the CVT transmission is such that there is no possibility of the driven shaft moving in the reverse direction. Therefore, engineers include various additional mechanisms in this system. When the driver switches the box to reverse mode, these additional mechanisms are activated.
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To avoid possible malfunctions during operation, you can move the gearbox mode selection lever to reverse only after the car has completely stopped. In various car models, to engage reverse gear, you also need to press the corresponding key. In this case, you can press it only after a complete stop. By doing this, manufacturers provide protection for the gearbox mechanism.
CVT gearbox: how to drive correctly
So, the CVT variator is a continuously variable automatic transmission, which greatly distinguishes this type of gearbox from its analogues due to its unique design. Gear shifting in a car with a CVT occurs smoothly, without jolts, delays, slipping, etc.
A car with such a gearbox accelerates easily, acceleration occurs without the slightest jerks, which to one degree or another can be felt on other types of automatic transmissions, including even the latest preselective manual transmissions with two clutches.
