Change shift points?

[Unclewolverine]

Tl, dr. Is there a way to change the transmission shift points without the mode select switch?

My 95 had the comfort vs power transmission switch. For the terrain on my mail route power mode is terrible. It shifted far too often and was super annoying, comfort was great. My 96 does not have the switch, I believe it was discontinued by then. I read that after the switch was removed they all just came in power mode, and it sure feels that way! Is comfort mode still somewhere in the computer and can be accessed, or is there another way to change shift points? I tried different settings on the tv cable, it really just seems to adjust firmness.

 

[kastein]

Not to the best of my knowledge. As far as I know on 96 the TCU microcontroller is 100% mask ROM, non updateable. 97 and up do have a serial EEPROM inside them but I have not managed to get my hands on the adapter needed to read the mask ROM in the MCU on them so I can figure out what the data in the serial EEPROM actually means or if changing it is in any way useful. I would assume for the time being that the shift points cannot be changed on the factory TCU.

If you want, you can do a manual shift conversion on it, however - the solenoid map for the AW4 is rather simple and is in my AW4 info thread over in OEM Tech. With a 96 you should be able to use a DPDT switch to select between TCU outputs and your manual switch and then simply put the DPDT switch in manual mode and shift with your manual shifter (your choice how you do this, several are available and you can do it as simple as a single toggle switch for 1-2 shifts if you never go over 2nd in mail delivery runs, or use a 1-2 switch and if you need 3rd just switch to automatic mode again) when delivering. 97 and later you can also do this but it will throw a handful of DTC codes and trigger the check engine light till you take it out of manual mode again and restart the jeep a few times etc.