So I did some research some days ago when I had extra time on my hands on tranny swaps. Although I haven't found all the pieces of info to make it 100% clear.


Lets take any Ford, no matter the engine size, as long as it's an EFI engine.


Now, I know an E4OD is all electronically controlled, and the tranny computer needs to work with the engine computer to be able to operate correctly.

I've read that some people swaped out E4OD for standard transmissions and having weird running problems, and replys saying you had to change the engine computer to one that had a manual transmission behind it in order for the engine to operate normally.

Why is that?



And heres the part that i'm un-clear of.

Lets say you have one with a C6, and you swap that out, for lets say a 5 speed. Do you still need to change out the engine computer for a manual tranny one? Cause the C6 doesn't have electronics on it, so why would it make a difference?



Or vise versa, put a C6 in a originally manual truck?



Thanks guys!

 

I am assuming you are working with a late '80's ford as that is what you have listed. The EFI has a profound difference on transmission selection at the factory. Whether your computer is an EEC-IV or an EEC-V (OBD I or II) makes a difference as well. You can use an automatic EEC (E4OD) with a manual transmission, but not the other way around, as that auto transmission 'talks' with the EEC. The E4OD requires the use of VSS as well as the appropriate EEC. A good choice for an auto tranny is an AOD as it is not an electronic shift. As in your C6 for 5 speed scenario, it should work fine. Hope this helps to point you in the right direction. And I hope I remember all this correctly, been forever since I owned my '95 mass air with auto.

 

I'm asking this not for any truck in my sig, it will be something I'll be doing soon to a 1988 Ford Econoline van 300 Straight 6. Swaping out the C6 for a 4 speed or 5 speed standard.

 

The first thing you have to realize is that in a truck with an electronically controlled trasnmission there is only one control box (computer) and it runs both the engine and transmission, so if you remove that trans the computer won't get any response from the trans sensors and control solenoids that it expects to be there so it goes into "limp" mode which also affects engine operation. But trucks originally equipped with a manual or non-electronic auto trans got engine-only computers so you can swap in any other manual or non-electronic auto without any problem... because the EFI computer doesn't know and doesn't care.

 

Ah ok, perfect! That's what I wanted to hear.


Thanks!

 

My '91 F150 ran just fine without the auto trans it came with, even with the auto trans ECU. But it did give me 7 different codes complaining about the trans not talking to it.