My OD light has been blinking a bit recently. I pulled codes 23, 29, and 59.

23 = FIPL
29 = VSS
59 = 2-3 shift

I checked the FIPL adjustment, and it seemed to be within the range. I decided to do some upgrades to a bunch of the wiring and such, as the solenoid wiring harness was crap. I replaced the VSS, the VSS wiring harness, the MLPS, the MLPS wiring harness, and the solenoid wiring harness. I also cleaned the solenoid plug with electrical cleaner and compressed air. This fixed the code 29 (VSS), but i continue to have 23 and 59.

When driving sometime the OD light doesn't come on at all, but when it does, it comes on when the tranny shifts from 2-3. I don't feel the shift acting weird, just the light comes on.

I am thinking it could be a bad solenoid, or??? Anyone have any other ideas? It seems like it will be super difficult to test the solenoids while its still in the tranny (wish I had kept that old wiring harness to make it easier). I know I can drop the pan to pull the solenoid pack and test it, and may just do that. I'll also retest the FIPL voltage tomorrow.

Ideas?

What else does a code 59 mean?

 

Code 59 means there wasn't a large enough RPM drop in the correct amount of time during the 2-3 shift. Usually that is caused by the intermediate clutch. It is possible the you have a sticky shift solenoid, or more likely, a sticky 2-3 shift valve in the valve body.

 

Thanks for the response, Mark.

If it's a sticky shift solenoid, can that be tested electrically?

How could I know if it was the shift solenoid versus the shift valve?

Correct me if I'm wrong, but a shift solenoid is an easy fix (drop the pan, swap out the solenoid pack), but the shift valve is a little more complex? Would I have to replace the whole valve body? Or can I just replace the individual valve?

Is it bad to be driving with this problem? Will it cause other tranny issues?

 

https://www.ford-trucks.com/forums/1...ng-issues.html

 

Have you tried the rpm pick up on the ip gear cover mine showed in the transmission before it show on the gauge when it started showing on the gauge I replaced it and the transmission started shifting correctly

 

I replaced the RPM sensor on the IP case a couple years ago, and that fixed some shifting issues I was having then...

Update:
I purchased a solenoid pack. I just decided to go for it, as I had a relay go bad a couple years back and was leaving power on to the solenoids, and may have done some damage to them. Not sure, but I though it was a simple enough fix to rule them out.

I also just ordered the ATSG rebuild manual to give me some more insight on some of the inner workings of the E4OD. I will attempt to inspect, or even clean the 2-3 shift valve while the pan is off.

Any words of wisdom?