The truck is a 1992 f250 4x4 7.3 idi with the e4od. I’ve been dealing with a few very odd issues with the trans as of the last year or so. It will occasionally loose converter lock up sometimes for a split second or for 60 miles on the freeway, it will lock and unlock multiple times in a couple of seconds although that is very rare. It is usually accompanied by a hard 1-2 shift and falling out of gear sort of feeling particularly when you let of the gas for a second then get back on it. I’m getting no flashing od light, tried to pull codes and none were found. I changed the fluid and used the 4x4 filter. I cleaned the solenoid pack plug replaced and mlps with 95 up unit with the better connector. No led tail lights etc, when I pulled the pan I did notice that it looked rebuilt at some point truck has 226k and shifts great 99% of the time no shutter or slipping. It has a couple year old fipl that’s in spec, I have experience with bad fipls and this seems different, no erratic up and down shifting, I have a new one I’ll throw on this weekend. Sometimes it acts up multiple times a week and then will go away for months…anyways any help would be greatly appreciated this is my first truck and I don’t wanna sell it but it’s starting to get on my nerves lol. I got a couple vids of it acting up also if those would help, let me know.

 

Anyone who knows me knows that my first suggestion is usually to read the codes. This is the one exception to that rule. This issue will never set a code. Replace the MLPS (Manual Lever Position Sensor,) also known as the TRS (Transmission Range Sensor.) It's located on the driver's side of the transmission.

As this sensor starts to fail, the electrical resistance climbs. The PCM sees this as you moving the shifter from D to N. Since it thinks you want neutral, it obliges. A new MLPS/TRS will fix this.

 

I thank you very much for the reply Mark. Although I have replaced the mlps, it had the original tan one on there so I figured that was issue as well since I had to jiggle the shifter occasionally to get it start. I used the newer unit and repinned the connector. It works good and fixed the no start. I have it properly aligned as well. I have also replaced vss, tach sensor and have cleaned the ground near drivers side battery and the one on the trans pan. I’ve swapped relay for teca as well. The truck does have a banks transcommand, I think I will try disconnecting that as well.

 

Now would be a good time to read the codes. Here's how: www.troublecodes.net/ford

 

Okay I’ll try the test light method, I used a scan tool before and it was able to communicate with it but no codes were found. I still have never got a flashing overdrive light, I put a new shifter on so I can confirm the light and button works. Thanks for the info and link, greatly appreciated.

 

That's tricky when there are no codes. You should at least get code 62 when the converter isn't locking when it should, or staying locked.
Here's an in depth write up to hunt it down.

E40D: The Importance Of A Clean Trans Harness.

"no codes" should be "11" at least = system pass on your scanner. You wont have better luck with a test light. Mark's link just shows how you can do it. The scanner is easier.

Don't be surprised if you find out the pre- '94 controller is your problem. Earlier units were failure prone and notorious for this issue, along with having a vast amount of other poor shifting strategies and there isn't a code to tell you the trans unit itself is the fault. If everything else checks out, and by the age of all these trucks now, the odds are very high, it is.

 

Yeah we did get a system pass, it was on my dad’s rotunda star tester. He used work on these trucks back in day and is more familiar than myself, the truck is over a decade older than me. I think your right about the teca, I did throw a new fipl on it and it’s been good for last couple days but time will tell. Im thinking of going to a more modern controller like a us shift standalone unit if the issues persist.

 

You were right it was the tcm, I put in a us shift quick 2 controller and left the original tcm in place. Still no flashing od light with the two connectors unplugged. Ive been dailying it for a couple weeks with zero issues. Thanks for the help guys I appreciate it!!