Diagnosing F-4EAT Shifting Issues

[kunar]

I've got a friend that just bought a '96 escort with the F-4EAT automatic. The previous owner sold it because of the trans issues. I don't believe it's in need of any hard parts, but beyond that, i have no idea how this thing works or how to diagnose. It starts out in 1st but wont even try to shift till you get to redline. when it should shift into 2nd, it just revs like its in neutral. Hold the revs at 3-4k for a few seconds and it will eventually grab second. After you tease it into second, it will drive like normal, shifting up and down through all gears with nice clean shifts. Next time you drive it, you've gotta go through the same stuff to get it to shift. The speed sensor in the trans is damaged. Supposedly the PO damaged it in an attempt to replace it hoping to fix the problem. Beyond that, what kind of things could cause these issues? What tells this thing when to shift, is it vacuum or electronic?

 

[adsm08]

I had to go look this up since the Escort as a whole car is a bit before my time.

Looks like the F-4EAT is a hydro/mech trans, no vacuum input. It's all computers and hydraulics.

Looking at the clutch/band chart I would say that you issue is either with the 2/4 band getting stuck somehow or else it's in the valve body. If you can get at the band's servo piston without pulling the trans I would look at that first, make sure the seal isn't damaged and leaking internally.

 

[kunar]

thanks adsm, i was hoping you would see this thread

so, two things. do you think the speed sensor could be the issue? obviously that will be fixed first since its broken, but i suspect it's not gonna help the shifting issue

also, what's it take to change the valve body in these, it's pretty straight forward? can it be done with the trans in the car? thanks again!

 

[adsm08]

I don't know if the speed sensor will help or not. Since you know it is broken I would go ahead with replacing it and then see how it works.

Looks like the valve body can be replaced in the vehicle. Process looks similar to an A4LD. Spill it, drop it, glue it back up, and fill.

One other thing I just saw that might be worth checking on. This thing still has a TV cable. IIRC the problematic vacuum modulators on the A4LD serve a purpose similar to the TV cable on other transmissions. If the throttle valve cable isn't working right it could cause shifting issues.

 

[kunar]

you ford techs have any special trick for getting the speed sensor out? they tend to corrode into the aluminum housing of the trans. both on the 1.8 and 1.9, manual and automatic.

 

[adsm08]

Screwdrivers.

The 7.3 cam sensor had the same problem.

 

[kunar]

sounds good, thanks