>>what pins control gear selection.

First of all, pins don't control gear selection... you do! There are not individual pins on the TCM that directly indicate gear selection. This is part of the Transmission Range Sensor's function. There are, however, 4 switches in the TRS that the TCM uses as input (pins 1, 3, 41, 42) to determine which gear you have selected. Each gear selection will either OPEN or CLOSE each of the 4 swtiches. (PARK = close, close, close, open) (NETRAL = close, close, open, close)

Basically what I'm trying to say is if you are trying to figure out a way to manipulate the state of these switches to control gear engagement or shift scheduling, it doesn't work that way. The TCM flash software is responsible for these functions.

Shift scheduling and gear functions are controlled by the TCM software and uses engine sensors, tranny sensors, autostick (if equipped) switches, and constant values in the software code that cannot individually be flashed. The entire software would have to be modified, compiled, and flashed to the TCM.

>>how shift pressure is controlled.

This is the valve body's job. The Transgo shift kit will increase fluid pressure and flow. This reduces gear overlap and shift duration. Performance is increased, wear and shift comfort is decreased. This is a great mod!

>>and how I can controll them.

You'd need a manual valve body. This is not available for the A604.

>>maybe even how the software determines how to adjust shift >>pressure...

It doesn't at all.


EXTRA INFO-
The A604 is Mopar's first electronically-controlled ATX. This is why is has had many electrical and mechanical failures. It has been updated extensively and 2GNTs have a very reliable version of it. Our 1995 and earlier A604 TCM software is the cause of limp-mode and most reliabiliy issues generated by this tranny. The 1997+ versions are virtually bulletproof. Our tranny cooler is too small, we need one twice the size (15,000-20,000+ GVW). ONLY use Mopar 7176 spec ATF+3 fluid in the tranny. A new solenoid set is available from 1999, the old ones were easily clogged.


I have been studying our A604 TCM in-depth trying to find ways to modify it's software-controlled actions. I'm making progress and have found a way to modify gear shift scheduling and shift points. I'll give you give all the info about it when my testing is complete. It IS possible to increase the red-line shift point though. I'll be testing autostick compatibility with our TCM as well, although I believe a TCM swap will be neccessary. Note that autostick alone will not increase our redline shift point of 6500 and will possibly cause power and reliability issues.


What else would you like to know about the ATX and it's TCM?