My E4OD mystery... Random Shifting

[7.3IH_Eggrole]

On my '94 F350 E4OD I've been having trouble with my transmission wanting to do a lot of shifting. That is it will hunt from 1st to 2nd to 1st again then 2nd to 3rd to 2nd and so on. My O/D light seems to flash whenever it wants, but when it did (was on all the time, not just at idle) I got it checked and then I disconnect the batteries and went on and it hasn't flashed since, and I've checked the FIPL and it was fine. But I replaced it and had a shop check to make sure. The tachometer sending unit is working fine as best I can tell from the cab. I thought I might replace it anyway.
I have noticed that if I disconnect the batteries completely and reconnect them the transmission works like it should for a day or so, or until I put a grain cart behind it or some other extra load, but then goes back to the random shifting (No flashing O/D light), but I am not getting any hard shifts as if it were in safe mode. So I decided that I would come on here and see if yall had anything else to add to what I already knew to do. I see that maybe I should change the tachometer sending unit anyway. I have thought that the transmission fluid may be burnt and it may possibly need a filter. So I was wondering if yall had any other suggestions?
Thanks
Eddie

 

[LCAM-01XA]

How many miles on the transmission? I'm thinking if you got fairly low line pressure it wouldn't be able to hold the higher gear good, so it will drop down in the lower gear, then it would try to upshift again, and so on. When the O/D light is flashing, have you pulled the codes? If yes, what codes did you have? The blinky O/D light is the PCM's way of telling you something ain't right and needs your attention, simply disconnecting the batteries to reset the PCM is often nothing more than driving by the "ignorance is bliss" principle... Pull codes man, then tell us what you got.

 

[7.3IH_Eggrole]

there is about 400k on the transmission. I believe the code was 23???? but dont mark my word on that. Like I said the O/D light hasnt flashed (ignorance is bliss) since I disconnected the battery after visiting the shop.

 

[LCAM-01XA]

Wow, that's a lot of miles! Things do get worn out when you rack up miles like you did! Code 23 is the FIPL, but you corrected the issue, so that's off the list. Dunno man, maybe it really ain't building the pressure she needs to keep in gear under load... You can easily bump up the line pressure by doing what Marq and I have done with the EPC harness inline resistor, but I'd keep that as a last resort. Hopefully someone else chimes in as well.

 

[7.3IH_Eggrole]

Thanks MLSC, I hope someone can give me an idea.

 

[Mr_Roboto]

As long as the tach reading is steady the tach sensor should not be the problem.

I would give a shot at upping the line pressure.

In my time on these boards this is the first time I have seen a gear "hunt" in all gears, so it seems likely that it is an issue with the trans itself.

 

[topgunn]

Does the T/C unlock then lock again? Does the tack jump a few rpms when it happens? If it does, you might have a brake connection problem. The T/C is inter-connected with the cruise control and brake lights.

 

[7.3IH_Eggrole]

As long as the tach reading is steady the tach sensor should not be the problem.

I would give a shot at upping the line pressure.

In my time on these boards this is the first time I have seen a gear "hunt" in all gears, so it seems likely that it is an issue with the trans itself.

Yeah, thats why I couldn't figure it out. Nobody here has had this happen. Pressure it is then.

 

[7.3IH_Eggrole]

Does the T/C unlock then lock again? Does the tack jump a few rpms when it happens? If it does, you might have a brake connection problem. The T/C is inter-connected with the cruise control and brake lights.

I am not seeing any jumps, so I dont think is jumpin in and out of lockup. These are complete shifts and no O/D light. Thanks

 

[ericboutin]

The T/C is inter-connected with the cruise control and brake lights.

This is interesting to me as I don't fully even understand the T/C myself. If you don't mind explain this further.

 

[LCAM-01XA]

When the torque converter is locked the transmissions acts like a sticks-shift, as in there's a solid mechanical link between the engine and the driveshaft. Now, on a stick-shift truck, when you slow way down what do you do - you step on the clutch, then downshift. Well, with the E4OD there ain't no clutch to press, so it needs another way of disconnecting that solid mechanical link the locked converter provides - it uses the input from the brake lights, idea being that brake lights are an indicator of you slowing down, hence the need for the converter to stay unlocked. When you take your foot off the brakes and the lights go off, the converter locks up again, if you're in 3rd or 4th gear that is.

 

[MARQ2277]

Okay, I have an ATSG transmission manuel for the E4OD, and it's the standard for our transmission. Under Shift hunting it list possible sources as:

1. Fluid level high or low.
2. Check electronic engine control operation.

Under Erratic shifts, it states:

1. Fluid level.
2. Electronic engine control operation.
3. vehicle speed sensor.
4. Inspect vlave body bolts.
5. Inspect valve body sticking valves.

Anyway, usually it is electronic at this time. And, if you are interested, I can send you the test procedure on how to check the electronic issues, with a volt meter. It's not real hard, but you will have to take the floor pan off, so you can access the wiring harness a lot easier. Than it will be a matter of checking the impedance, and grounding of each solenoid to make sure the transmission is working, correctly, and then narrow it down from there.

Marq:
___________________________________________
1990 Ford F-250 4X4:
7.3 IDI with 120K on the clock:
ATS Turbo with waste gate:
Stage One Injectors (Oregon Injector Service):
Complete Return Fuel Kit (Oregon Injector Service):
DB2 Pump, cranked up with Cold Advance wired permanently on:
4” down pipe, 4” straight through exhaust stopping between cab and bed (no fuff on my stuff):
Torque Converter Lock Up Switch (On/Off/Lock-Up):
E4OD Line Pressure Controller (adjusted to fast/firm shifts):
4” lift w/Rancho shocks:
Big Fat Tires on custom rims:

Tows 1985 fully loaded heavy 28 foot RV (my house) everywhere:

 

[7.3IH_Eggrole]

OK, I'm gonna try a couple things and I'll let yall know what works. Thanks

 

[MARQ2277]

Okay. We are here for you, if you need any information. I have the manuel for the E4OD transmission, so let me know if you need something looked up, or what ever.

Marq
_______________________________________
1990 Ford F-250 4X4:
7.3 IDI with 120K on the clock:
ATS Turbo with waste gate:
Stage One Injectors (Oregon Injector Service):
Complete Return Fuel Kit (Oregon Injector Service):
DB2 Pump, cranked up with Cold Advance wired permanently on:
4” down pipe, 4” straight through exhaust stopping between cab and bed (no fuff on my stuff):
Torque Converter Lock Up Switch (On/Off/Lock-Up):
E4OD Line Pressure Controller (adjusted to fast/firm shifts):
4” lift w/Rancho shocks:
Big Fat Tires on custom rims:

Tows 1985 fully loaded heavy 28 foot RV (my house) everywhere:

 

[gsgIDI]

Hi,
Marq
I have had my 1990 F-350 CC 7.3 N/A off and on in two different shops for about three months trying to fix erratic e4od shifts. I have had the transmission rebuilt, new computer installed new TPS sensor installed. Finally problem was found it was the wiring harness behind tach shorted out apparently messed up original computer. Computer worked then didn't finally quit mechanic then replaced computer couldn't get codes what so ever. Most expensive repair lately $3500 clams, new tranny way more expensive than that. I am posting just for information. gsgIDI