E40D shifting hard...
 

I have a 94 250 w/ an E40D, 95K on the clock. Just started getting really hard up shifts last couple of days. Fluid is good; KOEO codes OK; KOER codes as follows: 536, 538 and 632. Any ideas where to start looking?

Thx!

Not an expert but i`ll have a go.
536 brake switch/circuit open or grounded. Possible brake not applied during test but check brake lights are working properly.
538 gas pedal not floored during test.
632 transmission control switch not cycled during test.

Yea those code are just user error and don't mean a thing. (unless of course test was done correctly no steps missed?)

Harsh upshift suggests computer entered limp mode however no codes to back that up.

All "upshifts" are harsh or?

Hows your speedo work, have a steady needle or jump around?

Got no codes to work with right off the bat so first thing I'd suggest disconnecting battery clearing memory, see if trans shifts normal again after doing so. (That would verify limp mode was entered)

Then drive it and see if problem returns after few miles, if so check codes again post back let us know what's going on either way.

^^^ X2 ^^^
I'm with Dan on this one..

My e4od has only 60k now, and since 25k it's shifted pretty hard at times when there was only light throttle applied.

First thing
When was the last time the fluid was changed.
Next
You should add some lucus trans ooze in it. (if you've done filter and flush already)

If the tq converter is starting to go and it's not unlocking, it will shift hard.

I stopped this problem in two trucks with a fluid change to Mercon V.

Worth mentioning yea ^^^^, all to often just assume the correct fluid is being used, never brought up/questioned.

It's kinda hard to put the wrong fluid in. MerconV is "reccomended" for all ford trans now. But anything but the Chrysler specific fluid will work, and that's clearly labeled "for Chrysler only"
MerconV fluid is only "nessisary" for vehicles made after about 2003 or so. I'm sure it has much different additives that can help.

Some people put type F in a E4OD thinking its the correct fluid, a force of habit kinda thing.

So what is the best and proper fluid? I need to change mine soon. Also, is their a flush additive to use? I too have an inconsistent hard shift issue.

You can use any type of mercon fluid you can find, but don't mix mercon and merconV.
I would say dump a can of seafoam into the trans and drive it 30-40 miles easy and then drain fluid, change filter, then refill, unhook return line from cooler and flush out 6 quarts while adding fluid to trans.
That will be a good start.

Mercon V, drain the TC via its drain plug and remove the pan changing the filter, you'll get all most all of it doing so.

The TC contains most of the 17+ quarts of fluid (4x4 version), only about 5Q in the pan.

Thx for the info. No speedo issue to report. I will cycle the battery connection and see how it goes. Filter flush and new fluid next.

After cycling the battery connection, went for a test drive...shift action smooth as silk now. Thinking back on what happen, I did have to add a quart of fluid to bring it back to the normal level, so I guess a low fluid level is probably what triggered the shifting problem. So the question is where did the that much fluid go? There are no visible leaks. I to got thinking about that and it came to me that I had the radiatior core changed out about a month ago. I'll bet they dropped a quart or so on the floor when they were disconnecting/connecting the all the plumbing...that's all I can figure. Thx again for the great advice from everyone...once again this site has saved me a bundle!

It is a good sign it returned to "normal" clearing the memory however one quart low wouldn't have made it go into limp mode or at least shouldn't have done so. While not an ideal condition being one quart down, it just isn't low enough to hurt anything.

Continue to drive normally, see if it goes back into limp mode or not. If it has a problem and is going to it do so, it won't take very long. If/when it does run the KOEO self test / check for stored codes post back let us know what you find.