transmission swap question

[lscotty]

First off I'm new here and will admit I'm totally retarded when it comes to all this programming stuff so forgive me if this is a dumb question or one with an obvious answer, I searched all over and havent found the answer yet. And this seems like the place that might finally be able to answer it.

So the short version is I have a 454 that had a 4l80e behind it both out of a 91 chevy 1 ton dually. If I swapped out the 4l80e for a 700r4 or a th400 what would happen? Would it start running wrong in anyway and need something reprogrammed to fix it? Or would there be no issues?

Now the longer version in case you need some other info.

I have a 77 chevy k20 that I just pulled the 350 out of and replaced it with a tbi 454 out of a 91 chevy 1 ton. I had the whole 91 chevy to work with and pulled the motor and tranny, complete wiring harness both motor side and from under the dash, all fuel lines and both gas tanks, and the radiator, plus some other random thing just in case. I've got the motor in and ready to go now the transmission is my issue. The donor truck was a 4x2 with a 4l80e. I know you can change the 2wd 4l80e to 4wd and put a transfercase on but I'd rather not deal with the hassle or the extra cash to do so. I have on hand a th350, th400 and a 700r4 all with transfer cases and in good shape ready to go. what if anything needs changed to make one of them work? I know they all bolt up but dont know what issues it is going to cause switching from the electronic 4l80e to a non electronic transmission or what needs done to make it work. The truck will be mostly offroad only when this is all done if that makes a diffrence.

Any advice or input is appreciated. Remember I'm a noob and know basically nothing about programing anything. I'm pretty sure I know what the PCM looks like but that would be about it. Im good with older engine stuff but all the electronic stuff not at all. Im willing to put it the work and time to learn just point me in the right direction.

[Six_Shooter]

Yes, the ECM will need to have a properly tuned bin file loaded to the EPROM (or adapter with new EEPROM), to disable trans control and codes so that the CEL will not be activated for trans signal loss/missing and so that the quasi LHM is not triggered.

I STRONGLY suggest using the 4L80E, it is by far better trans than a 700R4, and will take far more abuse than the 700R4. The TH400 is nearly as strong but lacks the overdrive.

[lscotty]

Thank you. I actually understood that it took a minute tho. That is exactly the answer I was looking for. Not real worried about overdrive since the truck will be offroad oriented so th400 or 4l80e then. The ECM part I get, EPROM im not sure about but I'll read more. You said or an adapter with new EPROM is that something I could possibly order and plug right in to have it work? I'll start reading up more about all this and see if I can learn how to do it. Im sure it would come in handy at some point. If I cant figure it out I guess I'll find someone that is able to do for me. Thank you again

[lscotty]

Looked at the ECM as I was leaving for work so I could look up info on it and it's a 7060. Did a google search or 2, not many since I am supposed to be working, but several forum posts I read said there wasnt a lot of people who have programmed this particular ECM. Would I be better off with a diffrent ECM even though all I want is the transmission stuff removed? Would using the ECM from a 90 chevy truck with the same motor work if all the pins on the plug were matched up? That would remove my transmission issue since 91 was the first year for the 4l80e. Or an ECM from a manual transmission truck? Wouldnt that be the same as my current ECM minus the transmission controls for the 4l80e or would that cause other issues also?

Sorry for all the noob questions. Just some thoughts I had from tonights quick search and exploring possible options.. Monday I'll have more time to research stuff myself.

[EagleMark]

2 different units, one for the 4L80E is a PCM and the one for 700R4 is a ECM.

Nothing wrong with either and the 7060 programs just fine.

What transmission are you using?

[lscotty]

2 different units, one for the 4L80E is a PCM and the one for 700R4 is a ECM.

Nothing wrong with either and the 7060 programs just fine.

What transmission are you using?

Right now there isnt a transmission in it untill I figure out the best/easiest/cheapest route to go. I have a th350, th400, and 700r4 all with transfer cases ready to go. Also have the 4x2 4l80e but to use the 4l80e is gonna be around $800 just for me to get a transfercase mounted on it. If I can save some money and use the th400 fairly easily thats prob the route I'd prefer. It's looking like the easiest for me would be to find someone to program me a new EPROM removing the unnecessary transmission stuff and order an adapter to install it. Or order what I need to do all that myself and learn how to do it. Every one here obviously knows a lot more then me about this stuff so I'm open to recommendations and advice.