Good Evening all,

As the title states, I am wondering if I can use an LT1 CPU that was intended for a manual transmission and use it with a 4L60E.

I am looking at getting a LT1 with computer that was originally connected to a T56 except the transmission is not availible. And rather then switch the car from auto to man I will just keep it auto.

I understand that the wiring harness will be different, or atleast I am assuming it will be, but could I not just get a wiring harness from painless that will have the connectors for an auto?

and my second concern is the computer. I have tried doing some research and I came across the below thread https://www.thirdgen.org/forums/ltx-...al-tranny.html From my understanding it seems possible to change a auto to man CPU by reprogramming it but is it possible to do the exact opposite and convert the Man to Auto?

Thanks in advance for any replies and have a good evening, or day depending on when you read this

 

Yes you can load either program into the pcm for the transmission you are using, sure you could get a harness from "painless" but it will do nothing more for you other than replace the engine harness with another and all of the wiring conversion stuff needed with making the stock harnesses work is still required.

 

if you can't get anything hit me up i have a pcm for and lt1 and 4l60e in an fbody and one for a b body. But on your question Im not for sure if you can or not. Seems that I seen something on the web about it I think.

NVM. you can lol

 

use these to repin your connectors

 

more

 

Well that is the CPU figured out but what about the wiring harness. I thought I remember reading that painless made a wiring harness that was pretty much a direct plug an play.

The reason why I suggested the painless was for that reason as well as the fact that I Amanda assuming the wiring harness from a T56 would be different then one for a 4l60E meaning I couldn't use it.

So I just my question is can I use a man wiring harness for an auto? Because i have no problem with modding the harness but I just thought I wouldn't be able to use it is all.

Thanks for the replies so far

 

I believe that you can just repin the PCM plugs like the pinout i posted above. if I'm wrong somebody chime in. If you are not comfortable with it they are companies out there to do it, but it is very simple if you take your time and do plenty of research and know what you are gonna do before you start.

 

The painless harness gets you NOTHING past what a stock LT1 harness gets you, you still need to do ALL of the same stuff.

They are "painless" for a hotrod that has no existing connectors and electrical system that needs to be interfaced. Beyond that its just a stock harness with a few things like evap, air injection, etc removed.


Yes you can use the T56 harness, you'll need the pins and connector body from a 4L60E and to add the wiring in for it. Its not simply repin because none of the T56 connections other than the VSS are the same, the 4L60E connector is a single body that all of the wires run to the pcm connections and power supply.

 

I was assuming that he knew he would have to have the connector for the 4L60e.
magnashift.com has the pigtail for $39.

 

When you tell someone they can "just repin" it can easily imply that they only need to "just repin" , which isnt the case, repinning something involves only moving the pins to a different location when it still matches up, the 4L60E uses quite a few more wires to control it than the T56 uses for its reverse lockout and cags, and will require a good bit more than repinning.

 

he said he had the PCM figured out so wouldn't that mean all he needs is the wires in the proper location and the connectors for the 4L60e? Not trying to be a smart*** about it im just asking a question.

 

Yes he needs the correct wiring in place for the 4L60E


But it is not as simple as "just repin it"

There are 3 wires from the pcm to the T56, there are quite a few more for the 4L60E, so you cannot "just repin it", you dont have anywhere near enough pcm pins to do so, just buying the pigtail to the transmission only gets you part of the puzzle.

 

ok when I done my swap I just had a harness with a 4L60e already I just took it apart like POCKETS post on doing the harness, I just wasn't thinking about not having enough pins lol

 

You can cut a pair of 4L60E connectors from the JY. One for the trans, one to salvage the pins as the connector uses the same pins as the PCM