I have a 1996 F250 4x4 with a Turbo Diesel 7.3 and an E4OD. I just had the trans rebuilt. I put a temp gauge on it when it was rebuilt. The temp has never gotten over 160F. It drove great for the first 3 weeks....no problems. Then while driving at about 25mph it was like it went into neutral. Pulled over, put it in park then tried again. It went into reverse ok but when put in the O/D position there was nothing. Put it in 2 and it went into gear and would move with no slipping but no upshift. Towed it home and called my rebuilder. He said it sounded like the rear sprague so I pulled the trans and sent it to him. I scanned it for codes first and found one concerning the range sensor. I put on a new sensor and also rebushed the linkage in the steering column.

My rebuilder tore the trans down and the only problem he found was the detent spring was bent due to the bad linkage and was causing the fluid to bypass when put in the O/D position. I put the trans back in...adjusted the new range sensor and put it into the O/D position and was happy to feel it go into a forward gear. Took it out for a test drive and no upshift!
If I drop it down to 2nd then it changes to 2nd. back up to o/d and no shift! Get the RPM up to about 2800 and it shift to 3rd....hold it at 2800 and it will hit O/D. release the throttle and it goes back to 2nd. Speedometor works steady and when driving with the scan tool hooked up it matches the scanned MPH. The scan tool also shows the range sensor correct gear to gear. I changed the valve body, seperator plate and the solinoid pack. Same problem..........any ideas?

 

My brother had a tran problem close to that on his 95 psd. Turned out being the plug in on the drivers side of the trans. It was a bad connection. You might try putting some dielectric grease on your termemals

 

sounds like your VSS to me. try cleaning it first if that doesnt work try a new one.

 

You think that is possible even tho' the scan tool shows the VSS matching the speedo? I'll give it a try because I'm desperate and will try anything at this point.

Any idea where it gets it's input speed from? Some of these trans have a turbine speed sensor but this one does not. Think maybe it gets it from the crank sensor? Also does anyone know if the TPS has anything to do with the trans control computer?

 

The range position sensor on the driver side of the trans might be bad...

 

im telling you my truck did the EXACT same thing. i ended up changing the VSS pigtail also. good luck

 

Ok...changed the VSS and the harness going to it even though it showed good on the data display of my scan tool. Changed the transmission range sensor and it's harness. Still the same symptoms. Zero upshift.

 

Ooo Rah....H&S 2/5 Comm

 

First welcome aboard. Second what do you mean with that?

 

Think that is just one former Marine greeting another.

Thank you both for your service!

 

Ah, OK, thank you, now I understand.

 

Semper Fi... H&S, Comm Squadron 28

Thank you for thanking us!

 

Mark Kovlasky (I might be butchering his last name) is the guy you need to pm and ask. Hes an ex ford transmission engineer

 

Neutral safety switch?

 

i have the exact same problem with mine and the pcm was bad. i replaced the pcm
and no more problems