Issues with an E40D transmission?

[stephen4785]

Im working on a 1991 E350 van thats been through 3 different shops and no one has fixed the problem yet. It started off as the trans shifting out of od at speed and not going back into od until you shut off the engine and everything cooled down(sounds like wiring issues). The van went to a trans shop who promptly pulled the trans and rebuilt it. Gave it back to the customer and the same problem. Then the trans shop swapped in 2 more transmissions, pcm, and 2 different transmission solenoid packs and it still had the same problem. That transmission shop rolled it to another trans shop. That shop disconnected all of the electronics from the van and said they hooked up some sort of diagnostic tool that they use and the trans checks out. But that shop doesnt deal with wiring. So now I have it.
Now it has even more issues. The od light is constantly on(not flashing) and cannot be turned off. When you shift it into drive it feels like its starting off in 3rd or 4th. When you shift it into 1st it takes off just fine. I checked voltage from the neutral safety switch to the pcm and the pcm is getting signal that the trans is in drive but Im not getting any voltage from the pcm to the shift solenoids. I told the owner that I can continue chasing down wiring and fix the problem as well as run new overlays for the harness or I could just wire in an aftermarket controller like a USShift/Baunum controller and it would eliminate the pcm issues as well as the harness issues(27 year old wiring).
So my question is-are these aftermarket stand alone controllers worth my time and if not then does anyone have an idea why the od light is constantly on and thew trans not taking off in 1st gear while in D?
Thank you

[red89notch]

Is the cluster working properly? I believe instrument clusters have inputs into the shifting on those.

[BP]

Is the cluster working properly? I believe instrument clusters have inputs into the shifting on those.

I remember bulletins about dirty MAF sensors messing with E4ODs as well, assuming it's a MAF car.

[shumpertdavid]

I have installed 3 of the older Baumann controllers and they work great. It's a little work setting up shift points and such, but pretty simple on them. I can't vouch for the newer stuff they are producing. My last install was 2012 or 2013.

As far as the current issue, if it's in limp in mode, it will usually take off in 2nd gear and may only have 2nd and 3rd. By pulling it manually into first, you bypass the electronics and likely why you have 1st gear then. I'm not a transmission guy, but have worked on the electronics off and on over the years. I'd start by opening the wiring loom for the trans and make sure it doesn't have damaged wires or insulation from oil, chaffing, etc. Have you tried unplugging the OD switch to make sure it wasn't something shorted or internal with it?

Did a KOEO test give any trouble codes for the transmission? Ford diagnostics pretty well sucked in those years, no scan data, etc makes it tough.

[hotrod66stang]

The first gen Lightning (93-95) E4OD had issues similar to that. The transmissions would shift hard, or would "slip out of gear" and the motor would rev. The definitive fix was replacing the MLPS on the side of the tranny and the VSS on the rearend.

[RJDCobra]

When they don’t have electronics hooked up or missing power they default to 3rd gear take offs in drive...had a older 92 e4od diesel kick my ass from this. With ignition on and me pulling up and down on the solenoid connector I could hear the solenoids click. Replaced solenoid pigtail harness connector and fixed it. If you installed a new connector pigtail and rewired all the way back to pcm including repin trans wires in pcm you have done all you could do as far as wiring....you could also load test the trans wires to pcm with headlight bulb.

[JETFAST]

I think that year is tied into the third brake light for lock up control of the converter lock up cancellation, if the bulbs are burn out of the third light, it will cause a trans unit to not function correctly, as the bulbs being burned out cause a short in a circuits signal from the 3rd brake light specifically, or some shit like that.