Hi all, long time lurker, first post.

I want to start by saying thanks to this community, I’ve been applying the knowledge found here as I troubleshoot and repair my 1991 4x4 E350 7.3 IDI and my E40D transmission. That said let’s get to the point. I’ll try to be as concise as possible with my issues and what I’ve done in attempt to resolve.


Issue: Transmission shifts to 2nd-3rd very early (around 20mph) once the transmission is up to temp and hard shifting. Issues always present themselves after the 1st dive of the day but never on the 1st drive, regardless of length of drive. The transmission was shifting poorly. It got rebuilt. Worked great for one week, then worked exactly the same way the trans originally worked before being rebuilt

Repairs I’ve made;
Replaced RPM sensor and confirmed it passes OHM resistance test.
Replaced VSS sensor on transfer case dongle
Replaced TECA (tps) SENSOR. Calibrated it to 1.15 vdc @ idle & 4vdc @ WOT. Sweep thru voltage is clean with no gaps.
Replaced the sensor on the rear differential (think it’s also a rpm/speed sensor)
Replaced the MLPS sensor on trans
Cleaned all connectors on trans spotlessly
Tested EEC relay (good)
Inspected entire wire loom for damages (no damages)
Removed PCM/Transmission controller inspected all wires and opened it to confirm no electrical damage. (Previous owner replaced with a upgraded 94 year controller)
OHM out RPM & TECA sensor wires to confirm no ground/short faults
Had transmission rebuilt 3 weeks ago and all the common E40D known faulty internals upgraded (solenoid pack was carried over into rebuild, builder said the solenoids tested good on bench)

Another issue that is currently present though I do not know if it could be related to above. My rear ABS light and Parking brake light on dash will not turn off. Brakes work just fine (though I think my vacuum pump is starting to make bearing noise). I was able to get the RAB’s light to go away by un plugging the ABS controller box at driver side kick panel. Parking brake lights both does not go off. (Switch on parking brake peddle is good and rubber bumper engaging it properly)


Desperate for some help here fellas. I’m currently traveling the US in this van with my wife and we’re pinned down here in NJ until I can get this solved.
Thanks in advance!

Also to note, I checked the trans fluid today after another round of troubleshooting and the fluid was definitely contaminated with something. Didn’t smell bad or burnt.

Supplemental photos below for reference

 

Wow that thing is cool! Well, your TPS is set too low. You want 1.2V idle/ 4.5 WOT. (the 4.25 WOT is good enough though). Being sure the meter's ground is reading from a negative terminal on the battery, positive from the center TPS pin and the high idle solenoid is off/disconnected. This will correct the early shifts and make her hang on to the gears much longer (in fact, you may want to cheat it a touch and back it off down to as low as 1.17 or so, if she holds on too long, but don't cheat it much more.)

https://www.ford-trucks.com/forums/1...ions-only.html


Low vacuum (I just recently learned) is what's settings your Brake light, no doubt, giving that you claim the vacuum pump is going.

https://www.ford-trucks.com/forums/1...t-is-this.html


Most importantly however right now though:

"fluid was definitely contaminated with something. Didn’t smell bad or burnt."

UH OH! Pull the rad cap off and see if you have red ATF in your coolant ASAP. Ideally, you won't even start it again until you address this. Consider yourself broken down now, so you can fix a possible easy fix, or end up stranded with probably a very expensive and hard one.

 

Just a side note on TPS: I would say using ground from both, battery terminal and a wire on TPS connector and make sure the voltage reading is exactly the same. Also, values are slightly different with bolts being lose and tightened on TPS, not much though. Mine was set to 1.2V and turned out being 1.18V after tightening the bolts, so just about perfect. Takes time and patience.

 

The first thing to do before wasting money shotgunning parts is to read the codes. Here's how: www.troublecodes.net/ford

 

How would ATF be in my coolant? The trans cooler built into the radiator? That’s not a concern, The radiator is brand new. I put it in 2 months ago.

I had the TPS previously set to 1.2 vdc and it did the same thing. I don’t think it’s a TPS problem because it doesn’t do it when the truck is at temp and the transmission is cold. Only does the early shifting when the transmission gets to 100 degrees or higher. I also did a real warm up to the motor to set the TPS voltage instead of the cheat by unplugging the cold idle solenoid. though I kept it unplugged while I adjusted just in case.

 

I have a OBD 1 reader, only codes I have received are 14 & 99. The RPM sensor which was code 14 was replaced and it and the one that came out both passed OHM tests on the sensors and the physical wires. Code 99 is a solenoid fault code. Tested codes yesterday and today and none are being thrown. Yet the trans is still shifting like poop.

 

How does a new radiator eliminate the leak concern? Are you saying that a new radiator couldn't possibly have a leak?

 

Funny I was just reading that thread about the vacuum switch! Great minds think alike

 

This

is what I meant by contaminated. Not by another fluid but it’s new fluid and already looks dirty

 

Code 99 is an electrical circuit fault for the EPC (Electronic Pressure Control) solenoid. That's your problem. You have either a wiring fault between the computer and the EPC solenoid or a bad EPC solenoid.

 

Wiring is good, I got to the harness on the controller (PCM) and homed for shorts. I was thinking solenoid pack has a faulty temp sensor myself but haven’t been able to find a post with enough info to collaborate my suspicions. Builder told me he tested the solenoids for function. Any experience with that? I’m noticing the transmission avatar so safe to assume you know your way around these things?

 

99 - Transmission EPC circuit/solenoid failure

 

That’s very helpful, thank you! I’ll test those pins tomorrow. Just hope I can find a way to do it blindly from underneath the trans. Wish I had a pigtail with that plug on it to make my life easier.

 

yes Mark :knows his way around these transmissions"
he was an engineer for ford and helped design the E4OD among other transmissions

 

In the spirit of Occams Razor, the fact that you recently had the trans rebuilt and are now having problems would lead me to think the issue lies in the trans itself--like maybe the solenoid pack. You seem to have checked everything outside of the trans, so . . . .