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Discussion Starter #1
Has anyone gone into the electronics to have the Allison going into fast relearn??? If so, how did you do it and what Scanner did you use. I tried a snap on and another brand, that I can't remember and neither worked. Some help would be appreciated.


Thanks
 

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You need a tech II.
 

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I have only done it with a Tech 2. Before the fast learn procedure was made you just had to drive it for a while at different throttle angles while watching the adapts. At first they adapt pretty quickly then they become "converged" adapting more slowly. The goal was to get as many converged adapts as possible before giving the truck back to the customer.
 

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Discussion Starter #4
Is there a certain order or procedure to follow once the TAP's are cleared, ie, should I use about 1/4 throttle or 1/2 throttle as I go through all the shifts?? Also, do I need to do the same things in Tow Haul or will that just go off the regular shifts.


thanks for the help.
 

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There is no certain order. Basically there are many different TAP values for all conditions of throttle angle and engine load. Here is the long description from SI.


This transmission utilizes clutch-to-clutch shift control to achieve range changes. In every case, except shifts to or from Neutral, one clutch is exhausted and another applied to make a range shift. The handoff between exhausting and applying clutches is very precisely controlled by use of two PPC (Pressure Proportional to Current) solenoids. These solenoids are labeled "A" and "B" in the transmission, and are referred to as "trim" solenoids. For example, to make a 1-2 shift, A solenoid is used to trim pressure off C5 clutch, and B solenoid is used to trim pressure on C4 clutch. The transmission control module (TCM) modulates the current to both A & B solenoids, which translates to a proportional level of pressure to the clutch. In order to make a shift, the TCM uses software and calibration settings of several program parameters to determine the level of current sent to the respective trim solenoids. These parameters are referred to as "adaptive values". With a new transmission and TCM calibration, the adaptive values are set to base calibration level. The transmission uses the base calibration to perform the first of each type of shift. However, once it has performed a shift, the TCM evaluates the actual shift and compares it to an ideal shift in the TCM's memory. Based on that comparison, the TCM changes the settings of the adaptive values to a level that it believes will result in a shift closer to the ideal shift the next time it makes that type of shift. This is referred to as "adaptive shifting". When the transmission/TCM calibration is new, the TCM is in fast adaptive mode. In other words, the TCM is allowed to make relatively large changes in the adaptive values after each shift. Once the TCM determines that a given shift is close to its ideal level, it switches to slow adaptive mode. In slow adaptive, the TCM still is evaluating shifts and changing adaptive values, but is only allowed to do so in smaller increments. When a shift switches from fast to slow adaptive mode, it is described as "converged". The TCM is programmed to try to switch from fast to slow adaptive mode in as many as 15 to 20 shifts. It is important to understand that there are many different distinct shifts recognized by the TCM, and each of these shifts has its own adaptive values. For example, there are upshifts and downshifts to and from each range, as well as unique adaptive values for several different throttle regions for each upshift and downshift. The point is, it may take a significant amount of time before most of the shifts converge from fast to slow adaptive, and thus it is not unusual to experience somewhat harsh or unpleasant shift quality until these shifts are adapted.


TCC engagement is accomplished by a separate pulse-width modulated (PWM) solenoid labeled "F" in the transmission. There are adaptive values for this as well, and thus it will also require some driving for TCC engagement to converge.


If you are experiencing harsh shifts, it is important to verify whether the particular shift is converged. Use the Scan Tool to determine if the problem shift is converged.
<UL =BULLET>
<LI>If it is not, the TCM is still learning how to adapt that shift, and simply needs to be driven a bit more with the intention of performing more of the particular type of shift.
<LI>If a particular shift is converged, but still objectionable, it's good troubleshooting practice to reset the adaptive values for that shift back to base calibration level. This will automatically reset the TCM to fast adaptive mode. The vehicle should then be driven to allow the TCM to "re-learn" the shift. Many times this will correct the problem. It is possible to reset individual shifts without affecting the other shifts. </LI>[/list]
 

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Discussion Starter #6
That was extremely helpful. As my shifts are very rough since the addition of chip. When it shifts, it goes up about 300 RPM, a really good jolt. It has been getting better, but way to slow. I'd like to take it to a dealer and have them mess with it, but I'm sure that they will notice the extra power and raise the flag on my truck. I don't think any dealer will just take my word and put the tranny into relearn mode without test driving it. Hopefully I'll find a place in the next couple of days that has a tech II with the proper programs. If they don't have the newest upload with the fast learn procedure, is there anything specific I have to enter into for the preset TAP codes once I clear the old ones?


Once again, thanks for the help.
 

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It will smarten up very quickly. drive around town a bit and it will be perfect in no time.
 

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With a chip as mentioned, fast learn is not necesssary .... Plain ole take it out on the street and adapt the additional power that way .... Fast learn is more for repair and R&R in order to reset TCM, I would have to believe ...

"When the transmision/TCM calibration is new, the TCM is in "fast adaptive mode". Relatively large changes in adaptive values take place after each shift. Once the TCM has determined that a given shift is close to its' ideal level, it switches to slow adaptive mode. In slow mode, the TCM is still evaluating shifts and changing values, but in smaller increments. When a shift switches from fast to slow, it is said to have converged."

"RESET PROCEDURE for TECH2 Users.

Connect Tech2 Scanner as normal and acquire "transmission output controls" screen from the "Special Functions" menu.

--Clear all TAP Cells must be chosen. This clears all previous shift adaptives.

--Then Preset all TAP Cells. This sets all shift adaptives to a base value which will relearn over time.

OR

"Fast Learn Adapt Process" must be selected and follow the on screen instructions. The entire learn procedure will take up to 3 minutes as the transmission automatically applies and dumps clutch packs and relearns the new values. The final 3-4-5 shift will learn very quickly on highway in a few upshift/downshifts. "

Bring the power levels up slowly,boys .....

Mac
 
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