Hi, my dad just rebuilt a E4OD in a 1992 Ford F-250 with a 460 gas engine.... and when cold, the transmission shifts perfect, and kicks into Overdrive at about 45 mph. You can kick it in and out of OD several times, (I would say 10 times), with the Overdrive cancel button on the shifter. After a few minutes ,when it starts getting a little warmer, it gets more and more delayed going into Overdrive. Finally it will take 50mph to go into Overdrive, then a little warmer, it won't go into Overdrive until 55mph, a little warmer 60mph.... and then when it gets to complete operating temp, it completely looses Overdrive. The trans still shifts perfect in all gears, but has no Overdrive after at operating temp. If you let it cool back down, it does the same thing all over again until it reach operating temp, and it will no longer shift into overdrive once again.

You can push the OD cancel button on the shifter ,the light goes on and off in the dash, but has zero effect, it just stays in Drive. My dad has built automatic transmissions for 30 years, and has built alot of E4OD's, but has never seen a problem like this.

It sounds like to us that it may be a sticky 3-4 shift valve, that works when cold, but gets sticky when it starts warming up, causing the shift to Overdrive to be more and more delayed, until it warms up enough that it finally gets stuck, and looses Overdrive completely. We bought a bottle of Lucas Transmission Fix, and although it did seem to help, it still does the same thing.

Anybody have any suggestions on what the problem could be with this?

Thanks!! Brian

 

Just trying to get some suggestions before we take the pan back off of it, if anybody has any ideas.....

Thanks

 

Check for codes. Is the speedometer working well? Doesit jump or bounce around?

 

Thanks! We put our scanner on it, it has NO codes, and the speedometer works smooth with no jumping or other problems..... we've checked all fuses, they are all good....

 

No codes.....not good. You should at least get the System Pass Code 11 or 111 for KOEO tests and the same for stored codes(Continuous Memory aka CM). A 1992 truck may have two or three digit codes, but never both. Most likely it will have three since it has an E4OD transmission. Anything less than System Pass is a "fail"

 

Thanks, yeah, that what I meant, it does indeed have the 2 digit codes, and the only code it has is the 11 "system pass". What I meant above was that it didn't have any error codes.....

 

With no codes, and the speedometer working correctly the only two things I can think of are to verify the MLPS is functioning properly and aligned right, and verify that the TPS sensor sweeps smoothly from ~1.00 volts to ~5.0 volts once the engine is hot.

 

Is it leaking anywhere? My brothers truck had the same problem. The rubber part of the cooling lines under the radiator support was his issue. As the engine and Trans warmed up, the rubber line expanded too much and lost pressure. At that point, no overdrive. I replaced the rubber line and the problem went away.