Description of the variator on Toyota RAV4: resource, design and operation of the box

Author: Victor

Due to the fact that CVTs have appeared recently and finding specialists to repair them is problematic, it is believed that such a unit is not very reliable. In this article we will tell you what the resource of the Toyota Rav 4 variator is and what needs to be taken into account when operating it in order to prevent premature failure.

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Design and principle of operation

A CVT gearbox is the only type of unit that allows you to continuously change the gear ratio between the transmission and the power unit. The vehicle picks up speed without increasing engine speed.

The design of CVT cars of Toyota Rav 4 2010, 2011, 2013 and other years of production includes two sliding shafts. They interact with each other through a strap stretched between them. One of these pulleys is connected to the power unit and is considered the drive, and the second - the driven - is connected to the drive wheels. Both pulleys consist of two halves. When these elements move together, the strap is pushed out, and when they move apart, it falls in. As a result of a synchronous change in the radii of the parts along which the strap moves, the diameter of one shaft increases and the other decreases. This contributes to a smooth change in gear ratio. If the drive shaft is smaller than the driven shaft, the vehicle moves at a reduced speed. With equal pulley diameters, the car drives in direct gear. If the driven shaft size is smaller, the machine moves at higher speed.

Toyota CVT transmission

A torque converter device is used as a clutch in Toyota Rav 4 2014, 2015, 2016, 2022 gearboxes. This unit is large in size and weight. Its presence in the design allows for smooth starting of the car and eliminates jerking during acceleration. Thanks to the use of a torque converter device, the vehicle shifts faster from a low gear to a higher one if the driver presses the gas pedal hard. To allow the car to move backwards, the transmission uses a planetary gear.

The operation of the CVT transmission is controlled by a control system, which includes a central processor, a controller, and a shaft control unit. The control module receives information about the speed of the vehicle, the speed of the power unit, as well as the position of the gas pedal. In accordance with these data, the central processor selects the gear ratio for a specific driving mode. If the information about the rotation of the primary and secondary pulleys does not match, then the control module sends a command to the hydraulic system to change the size of the shafts. The operating pressure in the system is provided by a pumping device. The same unit lubricates the internal parts of the gearbox.

You can learn more about the operating principle of a CVT transmission from a video filmed by the Toyota Russia channel.

The pressure parameter in the system is usually not determined by the speed of the power unit, but is maintained proportional to the developing torque. As this indicator increases, the discs are compressed more strongly, which helps prevent the strap from slipping. The amount of pressure generated by the pumping device determines the speed of the CVT gearbox. The larger this parameter is, the faster the gear ratio will change. To lubricate internal parts and components, a special lubricant is used, intended for Toyota Rav 4 CVTs and produced by the car manufacturer.

Life time

Now let’s look at how long continuous variable transmissions last on average. According to reviews from owners, the unit is reliable and on average lasts about 100-150 thousand kilometers, without causing any inconvenience to the motorist. Only after this interval are the first malfunctions of the gearbox possible.

Weaknesses, problems of variators

Problems may occur in the operation of the Toyota Rav 4 variator:

Belt and cones - as the belt slides along the cones, especially during the initial movement, gradual wear of the notches is observed. They are located on the inside of the belt and serve as a working surface that provides the necessary grip on the cones. If the notches wear significantly, the vehicle's traction will decrease.

Step motor - used to change the gear ratio. works no more than six years. When the step motor fails, it feels like the CVT is operating in single gear mode.

Belt wear (https://www.transakpp.ru/uslugi/cvt-ill.html)

Bearings - the destruction of bearings is accompanied by an increase in vibration, extraneous noise and the hum of a continuously variable transmission.

Pump and valve - malfunction occurs due to the use of low-quality or contaminated oil. First of all, wear of the valve is noted, which begins to jam, hang, knock, and then the pump may fail.

Heat exchanger – over time, there is a decrease in the efficiency of oil cooling in the CVT. This is due to the gradual clogging of the heat exchanger, which also leads to a decrease in efficiency.

Signs of a CVT failure

You can identify an impending breakdown of the Rav 4 variator by the following signs:

The car jerks when starting or driving, even when you gently press the accelerator pedal. This sign indicates a stuck oil pump valve.

The appearance of extraneous noise due to bearing failure. The decrease in their resource can be affected by:

• use of transmission oil that does not meet the specifications;
• overheating of the continuously variable transmission;
• use of defective or low quality bearings after repair;
• electronics failure due to failure of any sensor;
• operation of the machine under high load conditions.

Variator belt (https://www.transakpp.ru/uslugi/cvt-ill.html)

Basic faults

Transmission problems do not always appear gradually. Therefore, if the variator breaks down, it can quickly lead to the inability to control the car.

Damaged metal variator belt

Failed differential flange

Worn damaged support bearing

CVT repair

What problems are typical for CVT and how to repair the box in a car with a 2-liter engine or another volume:

1. Failure of the planetary gear set. When the unit operates under high load conditions, this leads to the destruction of the gear axes, and as a result, their teeth break. In this case, the teeth must be replaced.
2. Oil starvation. In the absence of lubrication and the engine operating at high speeds, when the car is used off-road, damage to the planetary gear occurs. You can see such a malfunction when replacing the filter device. The magnets installed in the tray collect wear products in the form of metal shavings; you need to inspect them. If the vehicle's mileage is more than 150 thousand km, and the size of the steel chips is more than 1 mm, this indicates that a chain reaction of gear destruction occurs during the operation of the unit. If you do not take any action, the gearbox planetary gear may damage the pumping device and other components of the gearbox. In this case, repairs will be expensive.
3. Front gear failure. When operating a vehicle in aggressive conditions, damage to this part occurs. The wear products of the element ultimately damage the ring gear. If you do not solve the problem in time, the presence of metal shavings can damage the rear planetary gearbox. As a result, the clutches will fail.
4. With intensive use, especially in off-road conditions, rapid wear of the support bearing devices occurs. We are talking about parts located on the primary and secondary shafts. Fixing this problem is quite difficult, since you will not find bearings for Toyota CVTs on sale. CVT parts are not available on the aftermarket. Therefore, to solve the problem, you will have to look for bearings at a car disassembly or buy similar ones in size and turn them on a lathe to fit the dimensions of the installed parts. This repair option is considered the cheapest.
5. Sensor failures. CVT transmissions are equipped with a large number of different electronic controllers designed to read data and transmit it to the control unit. The failure of one sensor can affect the functionality of the CVT as a whole. If the diagnostics show a failure of the controller, it is necessary to carry out a detailed check of it. It is necessary to check the connectors and contacts. Often the cause of malfunction lies in damage to the plug.
6. Malfunctions in the operation of the control system. If the central processor fails, the transmission will not work. If the control module is malfunctioning, but is still functioning, the gearbox will work, but intermittently. It is better to entrust the solution to problems in the operation of the control unit to professionals. Sometimes it is necessary to reflash the unit, but it is almost impossible to do it at home.
7. Broken drive belt. Due to rapid wear and improper use, the drive belt may break. Its links can scatter throughout the gearbox and damage other components of the variator.

Damage to the differential flange is especially dangerous. The drive for the so-called transfer transmission passes through a flange on the differential housing. This element has thin walls and in practice problems often occurred when the part burst due to operation under constant high loads. This leads to lubricant leakage. If it is not detected and resolved in a timely manner, the transmission fluid may completely drain from the box. In addition, the flange will crumble in the system and its fragments will fall on the gears of the transmission, which will lead to damage to transmission parts. The difficulty of repair lies in the fact that differentials for CVT gearboxes cannot be found on sale.

The car owner has the option of purchasing a new complete unit, which will cost more than 15 thousand dollars. The problem can be solved by installing a contract variator, but finding such a unit on sale is problematic. Moreover, the cost of such a unit will be quite high. The best way to solve the problem is at the stage of oil leaks and cracks. In this case, any suitable tightening sleeve must be pressed over the damaged flange and traces of leakage must be removed. But keep in mind that it is impossible to give exact guarantees about the durability of such a solution. Usually, after such manipulations, car owners try to sell the vehicle as quickly as possible.

The Automatic Transmission Technology channel has published a video showing the process of repairing a Rav 4 transmission with a broken belt.

Rules of operation and maintenance

What nuances should be taken into account in order not to reduce the resource of the Toyota Rav 4 variator:

1. Do not start moving from a standstill by pressing the gas pedal all the way. The structural elements of the gearbox are subject to high loads, which will lead to damage to parts.
2. Do not tow other vehicles. Towing trailers is also not recommended. CVT gearboxes are designed to work with a certain vehicle weight and cannot be increased.
3. Reverse gear cannot be engaged or disengaged until the car has come to a complete stop.
4. Try to drive less at top speed. This may cause the engine speed to fluctuate.
5. Avoid wheel slip. Cars often slip when they get stuck in mud or snowdrifts. You should not try to drive out of an obstacle while rocking, alternately turning on modes R and D. This will lead to a decrease in the service life of the CVT transmission. It is better to put the car in neutral and ask someone to pull the car out of the obstacle.
6. When the emergency mode is turned on, the car owner needs to turn off the power unit of the car and try to start it again. If the box works normally after restarting the engine, you can continue to use it. If the emergency mode remains, then diagnostics of the unit is required, and it is advisable to perform it as quickly as possible.
7. During the cold season, always warm up the transmission. The car engine heats up faster than the transmission, so when the engine warms up, you cannot assume that the transmission has also warmed up. At low negative temperatures, it will take at least 10 minutes to fully warm up the unit. Only after this is it possible to drive at normal speed. To warm up the transmission faster, you can turn on all modes on the gearbox selector one by one, staying in each of them for a few seconds. This will allow the oil to circulate faster through the channels of the transmission system.
8. During the operation of the vehicle, we must not forget about the need to regularly check the oil level. If diagnostics show that the lubricant in the system is less than normal, you need to check the condition of the gearbox. The cause may be a fluid leak. If wear debris is visible in the oil, and there is also a burning smell coming from it, the lubricant must be replaced. Please review the service book before performing this task. According to the regulations, the manufacturer prohibits the use of any oil other than Toyota Genuine CVT Fluid TC or Toyota Genuine CVT Fluid FE in transmissions. The use of consumables from other manufacturers may cause problems with the transmission. You may feel vibrations in the area of ​​the gear selector, and the lever itself may jam. In some cases, complete failure of the unit is possible if the quality of the lubricant does not meet the standard.
9. You cannot turn on the neutral gear mode at every short stop, in a traffic jam, at traffic lights, etc. If you know that you will be standing for a long time, turn on the parking sensors mode. Neutral speed is considered an emergency speed. It can be turned on if the car needs to be pulled out of a snowdrift.
10. Avoid off-road driving. Toyota RAV4 belongs to the class of crossovers, but the CVT transmission installed on these cars is not intended for regular operation on bad roads or rural areas.

The Automatic Transmission Technology channel provided a video, the author of which talked about what nuances to take into account during operation in order to increase the service life of the CVT gearbox.

What type is installed and its uninterrupted service life

The 2013 and 2014 models are equipped with the “Aisin” K111F V-belt variator, also called. The operating principle of a V-belt variator is based on pulleys, which contain two disks. They are connected using . The conical disks formed by the pulley can move or move apart, thereby changing the diameter of the pulleys. The cones are brought closer together by centrifugal force or hydraulic pressure.

The modern Toyota Rav 4 variator is equipped with a metal belt, which is made of several layers of a special steel alloy. The design of such a belt is divided into shaped parts, which are connected into “butterflies”. This device provides greater flexibility, reduced noise, and also increases the durability of the structure and its reliability.

V-belt variator “Aisin” Toyota Rav 4

If you compare modifications with an automatic transmission and a CVT, with the same engines, you can observe differences. The continuously variable converter shows better dynamics and reduced fuel consumption, and the car also starts more smoothly. Due to the fact that V-belt transmissions are usually installed in cars with relatively low engine power, a continuously variable transmission remains in service for a long time.

How long and trouble-free the Toyota Rav 4 variator will serve depends on the operation of the car. Considering that the Rav 4 is declared as a crossover, operating the car to its full capabilities may affect the durability of the unit. Similar units are also installed on passenger cars that do not have the off-road capability of a crossover. Therefore, the operation of the CVT box is more careful, and the resource is limited to 100–150 thousand kilometers.

The main reason for the malfunction of the Toyota Rav 4 variator is scuffing or wear of the pulleys with broken metal bands. Premature lifting of pulleys can be prevented by:

• do not start by pressing the pedal all the way;
• do not tow too much;
• Do not engage or disengage reverse gear until the car comes to a complete stop.

Of course, there were some defects in Toyota's all-wheel drive CVTs. The housing flange, which contains splines, tends to collapse, resulting in lubricant leakage. If measures are not taken to eliminate a possible defect, the flange is completely destroyed, fragments of which can get into the gears. This subsequently leads to complete failure of the transmission.

Another defect is in the primary and secondary pulleys. More precisely, the support bearings of the shafts of these pulleys wear out quickly. This often happens during the first few tens of thousands of kilometers. It is because of these factory defects that the reliability of the Rav 4 variator is significantly reduced, despite the predicted service life of 150 thousand kilometers.

Maintenance of the Toyota Rav 4 variator includes replacing the working fluid. In the operating manual, the manufacturer does not recommend filling the continuously variable transmission with oils other than Toyota Genuine CVT Fluid TC or Toyota Genuine CVT Fluid FE. Using a different transmission fluid may cause poor transmission shifting, vibration, seizure, or complete damage to the unit.

Advantages and disadvantages

To understand which is better - a CVT or an automatic, you need to understand the pros and cons of CVT transmissions.

Advantages:

1. Lower fuel consumption compared to automatic transmissions. Due to the absence of actual gear shifting and constant operation at the optimal speed, engines with CVT gearboxes operate more economically. The volume of harmful substances released into the atmosphere with exhaust gases is also reduced.
2. Smooth gear changes while driving. Thanks to this, when the vehicle speed increases, there are no jerks or shocks. Because of this, the service life of individual gearbox components also increases.
3. Reliability of the unit.
4. Good car dynamics.
5. Light weight gearbox.

Flaws:

1. Noisy. The effect of a CVT transmission can be compared to the noise a trolleybus makes while driving.
2. Transmission sensitivity. When using cars with CVT gearboxes, you must strictly adhere to the operating and maintenance rules. Otherwise, it may damage the structural elements of the gearbox and affect the service life.
3. Expensive and difficult to repair. If the structural components of the gearbox break down, it is problematic to find new parts. They are not always on sale.

Video “How to change the oil in a Rav 4 CVT transmission?”

User Andrey Florida in his video explained in detail and showed how to change the lubricant in the CVT gearbox of a Toyota Rav 4.

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Similar, but not the same

The solution used by Toyota brings to mind the Jatco CVT7 (JF015E) variator, which has been in production for almost 10 years, since July 2009 - this is the world's first variator with a mechanical two-stage gearbox. However, JATCO has supplied the CVT and gearbox in series, and torque is always transmitted through one of the gear pairs and the CVT. And in Direct Shift-CVT, the gear pair and the variator are used, so to speak, alternately in parallel - the moment is transmitted either by the gear pair or by the belt on the pulleys.

Insert video:

How does the Jatco CVT7 variator work?