I have a 97 F 250HD 4X4 5.8L/ 132k miles.
I was pulling a code for the VSS, changed it out and changed the rearend gear oil. the problem went away for a week, and came back. I found a post on here about cleaning the connections on the PSOM. I did that and it was good for about a 8 months or so. Now its acting up again. Hard shifts, late shifts, like it doesnt know what gear to be in. speed odmeter doesnt fluctuate or wave. trans doesnt slip and once you get to speed its ok, until it needs to downshift. Thie problem doesnt happen all of the time. ran the KOEO test and it passed DTC: 111. the KOER test gave me a DTC: 538 which from what I have read on here is that its operator error doing the test. I ran the test quite a few time each time taking more time to WOT, but still pulled the code. The engine runs well but surges a little at idle sometimes. I see that there are other 538 definitions, but not sure which go with my senario.
Is this a bad psom or something else. engine runs fine and might surge a little at idle. Only once did the overdive off light flash, but I still pulled no codes.

 

I went through a lot of trouble with the E4OD in my 93 FlareSide. Hard shifting, shudder, you name it. 90% of the problems went away with a complete fluid change to Mercon V and a bottle of Lucas Transmission Fix. The only remaining problem was the 1st to 2nd hard shift and it only happened when I would spend 15 minutes on the highway, get off at the exit, come to a complete stop, and then take off. 95% of the time, WHAM from 1 to 2. It seemed to be getting a little worse last week, so I checked the fluid after the truck cooled down overnight. Started it up, passed slowly through each gear and then checked the fluid. It was over-filled. Apparently, the Transmission fix was added after the full fluid change and nothing was ever removed to compensate for it.

I drained out 2 and a half quarts of Mercon V with the Lucas in it and slowly added straight Mercon V back in. It took two quarts to get it in the middle of the hatch marks. It's only been a little over a week, but the truck has not hard shifted again.

 

There are alot of threads on E4OD problems.. Do a search and your find alot of info.

New MLPS solved my shifting problems..

 

I believe I have read most of the posts on the E4OD problems. This is where I got the idea to clean the connections on the gauge cluster. Most posts are on waving speed odometer needle or no speed indication. I only have the shifting problem. I have religiously changed the fluid and the filter on the tranny every 35000 miles or so as recommended by a Ford mechanic. I dont feel that the issue is with the tranny, it seems to just not know when to shift. I have to let off the gas a little to get it to shift into overdrive. I will take another look and try different searches to see what I come up with.
I may take the chance and get a junk yard PSOM and see what happends from there.

I have been driving the truck and most of the time it seems ok, but it might not be shifting right, but its close enought that I dont notice it.

If the MLPS is bad or out of alignment would it cause a error code?

Ken

 

I delt with a bang shifting issue on my E4OD. It would drive fine for weeks and out of the blue it would bang shift HARD on the 1-2 shift on a slow drive away from a stop sign. Do that for a day and go away for weeks only to return/go away. I replaced the MLPS and problem solved. FWIW.

 

where any trouble codes stored when it was bad?
when it shifted hard did it seem like it was taking too long to shift into second gear?
mine would delay the first to second shift, and when it did shift into second it would shift right away into third. and to get it to shift into od i had to let off the gas a little. If this seems like your problem I will change that sensor out.

Thanks,
Ken

 

A bad TPS can also cause drivability and shifting problems without throwing any error codes. Use a meter to measure the output through it's entire operating range. You may have a bad spot in the sensor. An older style analog meter is easier to use when trying to watch the output signal but it can also be done with a DVM if you push slowly on the throttle/TPS.

 

I dunno...you can try this that and the other for a quick fix, but usually a rebuild is in order 90% of the time. My experience anyways. You may get by 6 more months or 6 more days with a fluid change, but it is acting up because it is not right mechanically. Just my 2 cents and a lot of experience in this area.

 

I am hoping that its not the trans, I would like to make sure before I do a rebuild. Seems to me that if it was the trans that it would act up more consistantly. Acting like a sensor is not sending the right signals to the computer.
I am going to test the TPS and check for any damaged wires.
Throwing a few bucks at it with the hopes that the trans is not the problem is the route that i am going to take for now. I will keep that in mind though. I am not going to change things out unless they test bad. That would be foolish on my part.