I Hate Conversions: Advice for 3-4speed Auto - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Aussie Pete · 08-25-2002, 17:54

I've tracked down a half decent EA S pack wagon MPI for a reasonable price but it's a 3 speed auto 1990. Is a conversion to 4 speed auto hard? Anyone done it?

(Yes I know the diff ratio is going to be wrong, but I'm thinking more of hoses, and of course ECU?)

old_mate · 08-26-2002, 00:46

IMHO, unless you REALLY REALLY REALLY want an auto, is to simply not bother and chuck a T5 in.

I imagine the 3 to 4 speed swap would be a pain the arse too.

Troutman · 08-26-2002, 04:15

This matter has been discussed before - this may help:

3 spd vs 4 spd:
http://discussions.fordforums.com/sh...highlight=auto

conversion:
http://discussions.fordforums.com/sh...highlight=auto

The Fonz · 08-26-2002, 04:20

The 3 speed is better and more reliable in my opinion than a 4 and costs less to maintain and fix. If you want you car to go harder you can always put a t5 with computer and the diff change as well.

Martin · 08-26-2002, 06:20

Umm why does a 1990 EA have a 3speed? I think the 4speed came in around August 1989?

08-26-2002, 07:10

I'd say someone was cheap and when the 4 speed blew up, replaced it with the much cheaper 3 speed.(4 speed Auto's brand new cost $1800)

The previous owner of my car had done this, and because I bought the car at auctions there wasn't much i could do about it.

I'm actually doing the 3 speed Auto to 4 speed Auto conversion as we speak. I have already removed the engine so that I could change the leaking oil sump gasket as well. You can leave the engine in to change the transmission, but seriously it's a really good idea to take it out... you can clear all your engine bay of any oil and change any gaskets that need to be changed.

To take the motor out it will require about 2-3 days, and there is nothing particularly hard about it as long as you have the right tools.

The actual conversion part is easy, just take the old trannie off, and stick on the new one. You will need the wiring harnesses for the 4 speed computer control but apart from that it should be just a bolt it on job.

I still haven't worked out whether there is a seperate computer located somewhere that controls the Auto 4 speed, or if it's inbuilt into the ECU, maybe someone else here knows. If the 4 speed has it's own computer i have never seen it.

SiX_iN_a_RoW · 08-26-2002, 15:41

I have been told that the 4 speed uses a different length tailshaft compared to the 3 speeder...is this correct? seems to make sense.
I'd say you would have to use the computer that came out on the 4 speed cars as the fourth gear is basically electronic overdrive correct? If so I dont think the information will be in the original 3 speed computer.
Once again this is all heresay...really need someone who has completed the swap to inform you.

Anthony

Aussie Pete · 08-26-2002, 16:10

I need the auto on this car for heavy towing. Otherwise, there'd be no way I'd consider an auto. I like the wreck idea too!

Just a point of interest. I thought the 4 speed auto came in EAs during 1990 (not 89). The first cars had an extra badge on the rear saying 4 speed electronic auto and I thought the 30th anniversary cars were among the first of these. Anyonew know for sure?

madEAs · 08-26-2002, 16:18

Yes the 4spd auto does have it own computer, um sits to the upper left of the pedal box from memory and i got it sitting at home if u need it. After pulling the 4spd out i would DREAD to put it back and going from 3spd would be quite hard, not impossible but hard, the 4spd loom is quite large has a round looking plug that goes to the auto computer. and yes the tailshafts are a different lenght, the t5 and 4spd use the same tailshaft. I would say the 3spds would take more abuse, the 4 spds are soo much smoother thou. Good Luck

Bass Crazy · 08-26-2002, 23:26

My EA started out as a 3 speed. I found that the gear changes were a little harsh, but with a few little tricks, it can be made to change smooth. Besides the whole diff gear ratio thing, I must give the 3 speed credit as it was one hell of a strong trannie.
I gave it hell for about 2 years and it remained in A1 condition.

If you are not worried about quick acceleration, the go the 3 speed.