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 AI machine learning algorithms

Through artificial intelligence and machine learning, transmissions can learn and make adjustments to stored values without those values being explicitly programmed into the transmission's computer (Transmission control unit or engine control unit).

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

As automatic transmissions age, their internal parts wear and the transmission fluid also wears out due to heat and sediments. 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. The transmission control unit automatically does this adjustment and store it in its memory continuously.

What adaptive transmissions do is to keep learning the shift pressure and timing values and adjust them accordingly by using the new values for the next application of shift pressure and timing. This learning process is continuous as the components and fluid age until the limit is attained. The values can also change when a transmission's component or fluid is replaced.

Adaptive transmission function should not be confused with throttle adaptation that has more to do with how responsive the throttle is, based on driving style. It is because of this misconception that there are misleading articles that guide people on resetting transmissions by putting key in ON position and pressing down the throttle.

 

Advantages of adaptive transmissions

Adaptive transmission function makes the transmission to last longer, enables the 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.

 

TRANSMISSION RESET

Resetting a transmission is resetting the transmission's control unit such that the stored shift pressure and timing values that have been learned over time are reset to default values. This is done using a bidirectional diagnostic scan tool that is capable of resetting the transmission.

 

TRANSMISSION RELEARN

This is the process whereby a 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.

 

WHY TRANSMISSION RELEARN IS NECESSARY?

When any transmission part is replaced or a transmission service is done, performing relearn process is necessary. For instance, when transmission control unit, solenoid, transmission fluid, clutches are changed, this procedure should be carried out. Carrying out reset and relearn is important to prevent transmissions failure after fluid change.

 

WHAT COULD HAPPEN IF TRANSMISSION RELEARN IS NOT DONE?

If a component of the transmission is changed or the fluid is replaced and transmission relearn is not done, it can result in 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 well or transmission that does not function at all.

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 a transmission has adapted its values to cope with worn clutches and fluids then suddenly a fresh fluid is introduced, it can cause a serious transmission malfunction. The transmission can begin to slip.

Even transmissions that have the lifetime fluid label should have their oils changed when the fluid has degraded.

Before the transmission finishes the initial relearn process, the driver might experience hard shifts. This is normal. But hard shift that does not stop after a reasonable period of relearn should trigger concern as serious hard shifts especially the ones that makes it to bang can destroy the transmission.

 

How long does it take a transmission to relearn after a reset?

Transmission relearn is something that happens continuously throughout the life of the transmission and it never gets to a time when the learning stops. It continues to learn and adapt as the transmission, transmission components and fluid age.

However, after you reset a transmission, you might experience rough shifts or mild bangs. This takes some drive cycles to smoothen and takes up to a day or some couple of days for some cars. It depends on the number of times you drive and how long you drive.

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