[Had a few Tri 5's]

My research shows that the 4l85e needs the Terminator X Max ecu to interface with the the tcm.

The X Max becomes the TCM. You plug it into the transmission and set your parameters in the Terminator X program. From there, you can set your shift points etc. Since you have just the MAX, you will need a stand alone controller,which you might have, or go with the X MAX ECU/harness. For a decent standalone you are going to be about 2/3rds the cost of the X MAX upgrade. TCI sells a controller fairly cheap. Compushift, FAST EZTCU are some others, and they go,up in price from there.

 

[Had a few Tri 5's]

Your Terminator X will control the engine only. Your TCM should be able to control your trans. The plug 180 degrees out is a real thing, but usually you only get a 1-2 shift. If you need to split the TPS signal, use a quality splitter or do a good splice. The Terminator X is prone to screwing up with any interference. You might get repeated TPS reset messages if everything isn't sanitary. The newer ECU's seem to handle it better. I am not sure how old your ECU is.

 

[Had a few Tri 5's]

Only real difference is gonna be the ECU size means a couple more mounting holes further apart, and some minor wiring. You will need a brake light wire hooked into the trans harness, gray wire and you will need a clean ignition wire to the trans harness, red wire. By clean I mean not the same ignition wire as the ECU.

Holley states :

The power supplying this wire must NOT be tied to the same point that the ECU switched power wire (red/white wire) is
connected to. If they are tied together, the transmission power will back-feed power to the ECU and the ECU/engine will not
shut off when the key is turned off. Use a relay or separate switched ignition power pickup point to supply power to the
transmission harness.

 

[Had a few Tri 5's]

Thanks Hotrod & Had a few.
Your information makes things much easier for me.
Russ

Of course you will also need to go into the Terminator program and enable the transmission ICF, it's under the toolbox tab. You will select the right transmission file. Once that is enabled, your gearshift icon will be active in the top bar. Click on it and you will select your trans type, max RPM, tire diameter, gear ratio, speedo enable etc. If you need any help with the setup let me know. I can send you some screen shots of the setup screens.