I have a 91 F250 7.3L diesel with 180,000 mi. The E4OD is original but well maintained as far as fluid changes. I have never had the OD light blink on me, so I'm guessing I won't find any fault codes to help with my problem. The unit has always shifted into overdrive a bit too soon, but I understand this to be a fairly common thing with this tranny. At least by looking at past posts anyway. It usually shifts into overdrive around 35-40 mph, but since I get no shudder it doesn't bother me. Just yesterday, it started shifting into overdrive as usual, but then around 45-50 mph it will shift out and stay there no matter what I do with the speed or accelerator pedal. I have been researching some possibilites, and understand the MLPS (Manual Lever position Switch), TPS (Throttle Position Sensor), or the VSS (Vehicle Speed Sensor) could be causing this. I make frequent 1,500 mile trips whith this truck, and have one coming up soon where I will be towing a 24 ft. trailer, so I wan't to get things as right as I can with out a complete rebuild if possible. Can anyone perhaps point me in the right direction on where to start from what I've written so far? I'm really not on familiar ground with trannys! Should I add on a trans. cooler for the trip, even though it will be in the winter? (Southern US I-10) Thanks...

 

After three transmission shops looked at it, and they all agree it needs rebuilt. It is slipping in 2 - 3 gear. All the external sensors checked out. One shop said they pulled some codes from the computer and another one said they could't get any and physically checked each sensor and they were all good to go. I priced a Factory rebuilt FOTP-RA E4OD unit from Bartow Ford here in Florida, and got them down to $1,800 dollars. It has a 36/36 unconditional parts and labor warranty on it, so I am going for it. I'll let you know how it goes, since it is being R & R tomorrow. extra $200.