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What is adaptive automatic transmission reset and relearn?



Modern transmissions are not as simple as they used to be. We can say that transmissions have become smart with the introduction of machine learning algorithms.

Two important parameters in the operation of an automatic transmission are shift pressure and shift timing. This is shift pressure and timing in the valve body of the automatic transmission that controls the application of the clutches.

As the transmission ages, the internal parts wear and the automatic transmission fluid also wears out. Because of changes in the properties of the fluid like viscosity and so on and also due to changes in the tolerance of the internal parts, the fluid pressure and timing changes.

What adaptive transmissions do is to keep learning the pressure and timing values and adjust accordingly by using the new values for the next application of pressure and timing. This learning process is continuous as the components and fluid age until the limit is attained.

Adaptive transmission function should not be confused with driver's driving style adaptation that has more to do with how responsive the throttle is based on driving style.

Adaptive transmission function makes the transmission to last longer, enables use of transmission fluid for a longer period, reduces frequency and cost of maintenance and improves shift feel and comfort.

Adaptive transmissions make maintenance free operation of the transmission possible. This is why many vehicle manufacturers claim to have maintenance free transmissions with lifetime fluids in them.


Resetting the transmission is resetting the transmission control unit such that the stored shift pressure and timing values that have been learned over time are reset to default values.


This is the process whereby the transmission relearns new shift pressure and timing values. It continues to learn to fine-tune these values. Relearning in some cars could entail following an instructed driving pattern, usually a drive and stop pattern, a number of times, over a particular distance. In some cars, all you need to do is to drive and the transmission performs the relearn procedure automatically.


When any transmission part is charged or transmission service is done, performi3a relearn is necessary. For instance, when transmission control unit, solenoid, transmission fluid, clutches are changed, this procedure should be carried out.


If a component of the transmission is changed or the fluid is replaced and transmission relearn is not done, it can result to rough or erratic shift and transmission damage.

If the transmission has adapted to the pressures of a very old fluid, replacing fluid with new one without performing a relearn might result in a transmission that does not function.

A word of caution!

The fact that these transmissions allow us to enjoy the car as it ages does not mean that ATF should not be replaced when necessary. A degraded fluid can accelerate clutch wear. When the transmission has adapted its values to cope with worn clutches and fluids and suddenly a fresh fluid is introduced, it can cause a serious transmission malfunction.

Before the transmission finishes the initial relearn process, the driver might experience hard shifts. This is normal.

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