Dynamic ATF
exchange

Exchange scope: depending on the type of transmission, static exchange removes only a portion of the spent ATF (approx. 40–60%), whereas dynamic exchange is nearly twice as effective and enables the exchange of almost all of the ATF in the transmission (approx. 90–100%).

Duration: in most cases, a single static exchange is faster because it does not require the use of any device. Possible exceptions include transmissions for which the manufacturer requires a connection to the external lines of the transmission to perform a static exchange. It is worth remembering, however, that achieving a complete ATF exchange using the conventional method requires repeating the entire procedure multiple times. This is much more time-consuming and may still not be as effective as a dynamic exchange.

Risk: regardless of the method used, a proper initial assessment of the condition of the transmission before the ATF exchange is essential to minimizing the risk of potential problems.

The term "lifetime fill," used by car manufacturers, suggests that the ATF in an automatic transmission does not need to be changed throughout its entire service life, which is a myth in real-life conditions. Over time, ATF loses its properties due to temperature, friction, and contaminants generated during the operation of the transmission. Transmission manufacturers (e.g., ZF, Aisin) provide for periodic ATF exchange in their service documentation, especially under increased load, usually at intervals of 45,000–60,000 km or shorter. Failure to exchange the ATF often shortens the service life of the transmission, despite marketing claims about the "lifetime" durability of the ATF.

There are several main types of automatic transmissions:

• Conventional hydraulic transmissions using a torque converter and planetary gearsets.
• CVTs, in which gear ratios change seamlessly thanks to a system of tapered pulleys and a belt (or chain). Due to their design, they are particularly sensitive to ATF quality. Failure to change the ATF causes rapid wear, even at relatively low mileages, for example, just over 100,000 km.
• DCTs/DSGs are dual-clutch transmissions whose design resembles that of a manual transmission. Power transmission is handled by two clutches that operate alternately, depending on the selected gear.

ATF plays a key role in an automatic transmission and performs many functions. It lubricates mechanical components, reducing their wear. It also acts as a hydraulic medium, enabling the control of clutches and brakes to change gears. It ensures the proper condition of friction linings and seals. ATF also helps to dissipate heat, protecting the transmission from overheating. Additionally, it helps clean the system by picking up fine contaminants and directing them to the filter.

A distinction is made between normal and severe vehicle operating conditions, which directly affects ATF exchange intervals. Normal conditions mainly involve smooth open-road driving and mixed driving, with moderate loads. Severe conditions include frequent city driving in traffic jams, towing trailers, a sporty driving style, high or low ambient temperatures, and driving with a heavy load. In such cases, the ATF loses its properties more quickly, and shorter exchange intervals are recommended.

Yes, but the vehicle should be thoroughly checked during a test drive. It is also necessary to check the history of the vehicle (as far as possible) and conduct a detailed interview with the owner or user of the vehicle to determine whether they have noticed any irregularities. Before the exchange, a small amount of the ATF must also be drained to check its quality (general condition, odor, amount of metal shavings). If there is a risk that the ATF exchange will worsen problems identified during the transmission inspection, the customer should be informed, and further steps should be decided together, with consideration of the possible consequences.

Jerking during gear shifts and delayed engagement are common symptoms of spent ATF. Then, if the ATF exchange interval is too long or the ATF is not changed at all, clutch slip may occur, manifesting in an increase in engine speed without corresponding acceleration or gears being held too long. The likelihood of transmission overheating also increases, accelerating the wear of its components and potentially leading to failure in the long run.

A visual assessment of ATF condition includes checking its color, odor, and the presence of contaminants. The ATF should roughly match the color of the ATF described in the product data sheet, and its odor should be neutral, typical of ATF. A dark color and a burnt smell indicate overheating and a loss of the properties of the ATF. The presence of metal shavings or sediment indicates wear of transmission components. Basic tests also include checking the ATF level according to the manufacturer's procedure and checking for any faults stored in the vehicle control units.

The device enables the following:

• automatically detecting ATF flow direction,
• visually monitoring the quality and progress of the exchange through two ATF sight glasses,
• controlling the procedure, including an automatic step-by-step mode,
• adding detergent,
• draining the ATF,
• adding the ATF,
• flushing the system (with the ATF or detergent, if the procedure requires it),
• dynamic ATF exchange,
• printing a process report (thermal printer).

Regardless of the transmission type — whether it is a conventional automatic transmission (AT), a continuously variable transmission (CVT), or a dual-clutch transmission (DCT/DSG) — the essential requirement is to select the ATF strictly according to the vehicle manufacturer's OEM specification. Using a lubricant that does not meet the specified standards can cause premature failures and costly repairs.

Although all these fluids are colloquially called "automatic transmission fluids," they radically differ from each other in terms of chemical and physical properties due to different transmission designs:

• Conventional hydraulic transmissions: require ATFs with high thermal stability and a very precisely defined coefficient of friction. Here, the ATF plays a triple role: it acts as the medium in the torque converter, as a coolant, and as the hydraulic ATF controlling the operation of clutches and brakes.
• Continuously variable transmissions (CVTs): use ATFs whose primary function is to prevent the belt or chain from slipping on the pulleys while still providing full lubrication. CVT ATFs are not interchangeable with other ATFs because they have completely different friction characteristics.
• Dual-clutch transmissions (DCTs/DSGs): combine the features of manual and automatic transmissions. They must ensure a rapid hydraulic response and effective clutch cooling (in "wet" versions). It is worth noting that some DCT designs (e.g., in Audi models) have two separate ATF chambers: one for the mechanical gear section (MTF) and the other for the control unit and clutches (ATF). Confusing these ATFs or mixing them will cause failures.

ATF additives, such as flushing additives and sealing additives, are used in specific situations. Flushing additives help remove deposits and contaminants from the system during a dynamic ATF exchange. Ravenol recommends using the ATF Flush additive before the first use of Ravenol ATFs or when ATF exchange intervals have been significantly extended. Sealing additives can improve the flexibility of seals and reduce minor leaks, but they are not a substitute for comprehensive mechanical repairs.

Preliminary procedure before the ATF exchange:

• test drive and preliminary diagnostics: carrying out a test drive to verify how the transmission operates and checking for faults in the control units (computer diagnostics),
• inspection for leaks: a thorough inspection of the system in a workshop for any leaks or loss of integrity,
• ATF sampling: draining a small amount of spent ATF to assess its condition (checking the degree of degradation, odor, and the presence of solid contaminants),
• lubricant selection: choosing the correct ATF, which must strictly comply with the specifications of the transmission and vehicle manufacturer (OEM standard),
• reviewing the ATF exchange and level check instructions: ensuring the availability of the necessary equipment, e.g., adapters, a diagnostic device supporting the required functions, spare parts, etc.

After the exchange, the ATF level is checked according to the manufacturer's procedure, taking into account the required transmission operating temperature and the method used for checking the level (inspection plug, overflow plug, or dipstick).

One of the most common mistakes in ATF selection is using an ATF with an incorrect specification or mixing incompatible ATFs. This can lead to jerking, clutch slip, and transmission damage. To avoid this, the ATF should always conform to the OEM standard specified for the given transmission type.

The preliminary vehicle inspection minimizes the risk of faults occurring after the ATF exchange. The most common post-service problem is insufficient adaptation of the control unit to the new ATF parameters (especially after the first exchange). In such cases, it is necessary to repeat the adaptation procedure. Usually, this makes it possible to fully restore proper transmission operation.

• Intervals: an ATF exchange is recommended after intervals of 45,000–60,000 km. Depending on the transmission type, manufacturers specify the following intervals: conventional hydraulic transmissions (60,000–125,000 km / 5–7 years), DSGs/DCTs (60,000–120,000 km), and CVT (40,000–80,000 km). Under harsh conditions (city driving, towing, heat), the interval should be shortened.
• Symptoms: a preventive ATF exchange is recommended even when no symptoms are present. This approach helps extend the service life of the transmission and ensure its proper operation without negative symptoms through regular ATF changes.

Each transmission service requires an individual approach. During service work, it is crucial to identify the causes of potential ATF contamination. We always verify the correct operation of the transmission, inform the customer about its actual condition, and advise whether a static or dynamic exchange will be the optimal solution. If the static method is chosen, it is possible to schedule another visit to perform a full dynamic exchange.

Typically at intervals of 45,000–60,000 km. This interval should be shorter in cases of intensive use (city driving, traffic jams, high loads).

Yes, that is true. In transverse Aisin transmissions (e.g., Volvo, Peugeot, Citroën, and Toyota) and Jatco transmissions (e.g., Honda, Renault), during a standard static ATF exchange, only a small amount of the ATF is replaced. That is why the dynamic method is particularly recommended for these transmissions.

• Lack of service: leads to a loss of ATF properties, overheating, increased friction, and the formation of metal shavings, which ultimately shortens the service life or increases the likelihood of failure.
• Incorrect procedure: using ATF with wrong specifications poses a direct risk of serious transmission failure, as does skipping the ATF level check or carrying it out incorrectly. Performing this procedure at the wrong temperature, for example, leads to an incorrect reading, which may result in improper transmission operation. To avoid costly faults, it is crucial to strictly follow the service procedure at every step according to the manufacturer's guidelines.