I've heard it said a few times in this forum that the 5AT "learns" how you drive and adjusts itself accordingly. Can someone please point me to link that describes how this works in more detail.

I went to the Nissan site and it doesn't mention anything about this. Web search didn't turn up much about the 350z 5AT transmission specs either.

TIA ...

 

i think it has more to do with the ecu adaptivity. in the same way that the stock ecu retards or advances timing, changes wot, etc., some people believe that it changes the 5at settings also. however, i've never seen any reliable info on that 5at being involved in any of the ecu changes. i did notice any difference in the tranny before or after having technosquare flash my ecu. but some people swear by it, so i'm sure someone will chime in with more info.

 

Aggro_Al! You're needed!

 

Nissan does a **** poor job of marketing one of the most advanced features of the Nissan 5AT.

The Nissan 5AT, like it's been mentioned before, is a real-time driver adaptive transmission. There are not many transmissions that have this capability. Most transmissions that they call driver adaptive are really driver selectable or fixed shift profiles. They don't really adapt but they have various shift profiles for different duties. Many basic torque converter based ATs will have at least 2 settings. A power setting that optimizes torque and a economy setting that maximizes mileage. Even the F1-Type auto transmission have several settings for different types of driving conditions (ie BMW's Drivelogic) but these need to be set by the driver manually. The more advanced Tiptronic-type auto tranmissions also have several profiles that have learning algorithms that remember and learn how the driver and the vehicle interact in different driving enviroments and situations. Most Tiptronic-type transmissions use a very basic algorithm and applies fixed shift profiles to the transmission controls. This is very similar to how the F1-type transmissions work. The only difference is that the transmission will pick and change the profile for you automatically instead of the driver having to select it manually. (One notable exception will be the BMW SMGIII. It will have automatic profile selection like the lower end Tiptronic-types.) Nissan employed a learning algorithm in the 5AT that will allow the transmission controls to work with the engine controls and truly learn how the driver and the environment react in real time. It constantly monitors various conditions and driver reation and adapts to the situation. One of the features that these high-end driver adaptive transmissions have over its predecessors is the ability to make simple judgement calls. In stead of having the transmission change to only to true/false statements it can use fuzzy logic to also understand mostly true/mostly false statments and change accordingly.

The biggest advantage to driver adaptive transmissions is that the transmission and the driver become synchronised. Many MT drivers comment about the control the driver has over a the transmission but, the driver adaptive system takes it one step further. Once the system adapts to you and you drive it properly, you can almost shift gears by thought. It sort of hard to explain unless you have one of these types of transmissions and really use it. Those that have the 5AT and use auto-mode frequently know what I'm talking about.

Check out the Infiniti website because they describe it better. Some of the other real-time driver adaptive transmissions include Porsche's Tiptronic S, Mercedes-Benz's AMG Speedshift, Aston Martins' Touchtronic 2, Volvo's Geartronic and McLaren's SLR Shifter. Check out their respective websites for more info. As you can see the Nissan 5AT is comparable to many exotics.

Infiniti 5-Speed Automatic with Manual Shift Mode

Porsche Tiptronic S Transmission

Mercedes-Benz AMG Speedshift

Here's a Siemens VDO press release from 2002 for the Siemens Adaptive Transmission controls. The Nissan 5AT is similar.

Siemens VDO AG Adaptive Transmission

 

Aggro, on a related note, will resetting the ECU put the transmission back in "learn mode" so that it can quickly adjust to a new driver?

Also, do you have a link to a page where I can read up on this in more detail? I'm very interested in this topic and the short blurbs given on the Infiniti/Nissan sites don't really help me with what I want to know.

 

Let's say Bob and Fred have two totally different driving styles. Bob and Fred each drive their own cars, each which are configured the same way, then the switch at 5k miles. Would they notice anything?

 

From the way I read it, yes, they will, but after a while (I'm assuming about a week or so?) the cars will adjust to their new drivers.

 

I don't know if resetting the ECU will do anything to the learning mode of the transmission. The transmission is always learning there is no way to override it. It constantly adds and analyzes new information and drops the old information as more info gets added. I don't think there is anything short of a flash reset that will put it back to factory condition. Just drive long enough and it will re-adapt.

Check out the link to the Siemens Press Release. Mercedes, Porsche and BMW may have some white paper technicals on adaptive transmissions. Also, try a Google or MSN Search for "Driver Apdative Transmission".