hi , I’m new here . I just recently bought my 2003 f250 and after having some shifting problems I’ve been doing a bunch of research and this site seemed pretty knowledgeable so thanks in advance I appreciate any help . I’m no mechanic and I’m traveling and living in the truck so I’m really hoping I can figure this out as efficiently as possible .
the truck has 95k miles , was apperently dealer serviced company truck for a quarry , they didn’t tow with it but it did sit for a long time at some point before I bought it . it’s a 5.4 with 4r100 transmission . it ran and drove great when I bought it , aside from being a little loud , the cat. Is replaced by a straight pipe . trans fluid looked good when I bought it .
I drove the truck about a week , had one instance of the battery dying so I got a jump and replaced the battery . I got the cheapest battery for my truck at Walmart in case that’s the issue ? . a couple days after replacing the battery I got on the highway and the truck wouldn’t shift past 2nd gear . I pulled over and there was transmission fluid dripping from the front of the bell housing , and my overdrive light was flashing . I took it slow back to town and refilled the transmission fluid , it was 1qt low . the only light on the dash is the battery light comes on and off a lot , I replaced the terminals and it seems to come on more now . the truck will drive fine in 1 and 2 , if I let off the gas at about 40mph the rpm will drop like it shifted but as soon as I give it gas the rpm jumps back up . reverse works great . I used the code reader at a parts store and it came up with p1000 drive test cycle not complete code , P0781 , and P0782 . I just read on here though , that the parts store scanners won’t read the codes and it needs to be a ford dealer ?
I’ve been driving it around town still and the trans temp stays in normal range , it has not leaked anymore fluid , and the fluid still looks new on the dipstick at least
what would you suggest I try next ? thanks again I really appreciate any advice

 

That scanner DID read the codes. P0781 and P0782 are codes that most scanners will not read.

These codes mean that there was no 1-2 or 2-3 shift when the computer commanded them. When you let off the gas at 40 MPH the engine will drop to idle speed since there is no engine braking in the lower gears unless you turn off the overdrive. That would be a good test - what happens if you turn off OD? Press the button on the end of the shift handle and the OD OFF light should stay on. Now, what happens if you let off the gas at 40 MPH?

 

ok I just tried that . the overdrive light did stay on when I pressed the button but the truck acts exactly the same when I let off the gas at 40

 

I think you need a pro to look at it. I think it's had a major internal failure.

 

thanks for your advice , it sounds like you know what you’re talking about . I’ll be stuck here for a while saving up money for whatever it takes to fix it . I’ve replaced a transmission in an s10 once , and I’ve watched some videos about my truck , I think I could swap the transmission myself if I get the tools together . I don’t think I can afford to have it rebuilt at this time , it would cost more than I paid for the truck , but a local junk yard has a supposedly good transmission for $600 . . would yo recommend that route or no ? thanks again

 

That's probably a good way to go. Be careful - this transmission weighs 270 pounds.

 

thank you sir , gentleman and a scholar . last question , is there anything I should replace at the same time if I do swap the transmission ? other than new fluid and filter

 

The radiator and the aux trans cooler. Both probably are full of contamination from the failed transmission.

 

I was driving today and thinking . I believe I misunderstood you before about the test I was supposed to do . it won’t shift past 2nd gear , so when I turned the overdrive off and did the test letting off the gas at 40 , I don’t think the overdrive button would affect it because it’s only supposed to be shifting to 3rd at that point ?? anyway I had an idea to put the gear selector on 2nd gear and try again and it did act different . it didn’t drop the rpm’s right away that time but acted more like engine braking . in case that makes a difference ? My bad . thanks again

 

Yes, I should have thought of that. When the shifter is in 2 the coast clutch is always on and the trans will only operate in second gear. So the coast clutch is working, but it doesn't turn on electronically when OD is turned off. This could be a bad solenoid body or a damaged wiring harness between the PCM and the transmission.

 

ill have to clean it up to check out the wire harness , previous owner left it caked in dried mud

 

Check the harness electrically. Looking at it is mostly a waste of time.

 

I wouldn’t know where to begin , I’d probably need a pro to check that part . I’m seeing some remanufactured solenoid blocks for pretty cheap online , and I think I could change one of those and a filter and fluid on my own so I’m thinking I’ll try that . Are all the solenoids interchangeable ? I saw something about some having pulse width modulation and other without but I’m not seeing anything about it on the websites selling them . thanks

 

Your trans would take the pulse width modulated solenoid body.

I don't know why you would change it, it won't fix your problem. But then again, it isn't MY money!

 

I guess I misunderstood again . not trying to waste money haha . I thought you were leaning toward it being a bad solenoid block but what would you recommend ? thanks