Sorry to bring this old old thread back up, but I’m looking at a truck to purchase and it was doing the same thing. It’s a 250 diesel, 96 with 110000 on it. Was wondering if it does this if I should just stay away from the truck?

 

Nothing wrong with the truck if it shifts firm, as long as the overdrive light isn’t flashing. That means there’s something wrong. From what I’ve gathered, a good cleaning of the valve body will stop most of the harsh shifting. My truck did it with only 25k on it though, and was like it from new from what im told, so no that’s sure how it got that dirty in a short amount of time. But even the guru mark, hasn’t really been able to completely solve the mystery.

A good trans service, and new mercon 3 fluid, and possibly just cleaning the valve body, will go a long way in making sure it’s going to operate appropriately.

 

UNTAMND would you possibly be able to email me? I have more questions just about the whole truck that wouldn’t belong in this thread? If so my email is justin.witt248@gmail.com. Thanks!

The light does not flash. Only way I can describe how it shifts is it feels like it has a massive shift kit in it lol. I wouldn’t be afraid to do the work on the transmission myself as I’ve done that sort of work before.

 

Either someone installed a shift kit, or something is wrong. It could be something very simple or something major. Reading the codes would tell the story. And these trucks are not easy to read the codes, you need a pretty high end scan tool. The parts stores that read codes CANNOT read these codes.

What if the cause of the harsh shifting is a bad sensor? How will cleaning the valve body help?

MERCON V is the correct fluid. There never was a MERCON 3 fluid, it never existed. MERCON used to be the right fluid, but it has been discontinued. MERCON V was changed and is now the right fluid.

Once you have the codes I can help direct you to where the problem lies.

 

so will this be obd1 or 2? I have a Bosch unit that does obd2, and my uncle has about the same one that is obd1.

 

I have not had good luck with mercon V fluid. I know it superceeded mercon fluid Mark, but it’s just different enough to make some transmissions shift weird. I’ve removed and replaced with cheap universal ATF, and it was back to normal.
My mistake about mercon 3 fluid. The universal fluid was mercon/dextron3.

Mark, we have had a lot of conversations in the past about this trans issue. NO ONE has figured it out, from what I’ve read. Aside from when people just replace the whole transmission, this problem is just lived with.
My truck has had the hard shifting since new, my grandfather bought it. I acquired the truck at 25k, and it had it. I don’t believe it’s the valvebody, but people who have replaced them, seem to have had their problem go away... possibly due to new sensors and solenoids or whatever.

Ive has my truck on the snapon or Mac code scanner that can give real-time data streaming, and from what I remember, there were no codes at all at that time, and it was shifting hard. That was many years ago though, but I also remember taking it to the transmission shop in the city. They didn’t have any idea either.

Ill look into it again, and try to find someone with an adequate scanner. It’s not easy anymore. These truck have been obsolete for a few years.

 

Valve body, sensors, and solenoids are three different things. Changing or cleaning the valve body doesn't change or clean the sensors or the solenoids.

 

Mark... I was passing along information. If you read what I said, it was “from what I gathered”, meaning, it’s not my info.
You can not deny the fact that there is a huge lack of understanding on how these transmissions work. You, are the only one with the insider information. And even then, you want codes and will rely on the onboard diagnostics to help diagnose the issue. Even the transmission builders don’t know, or they are keeping that information to themselves.

The lack of people having access to expensive diagnostic equipment is also a big issue. Because these trucks are obsolete, you need to find people who have held onto their old computer scanners instead of trading them in for new obd2 tools.

 

I'm able to read ALL of the codes on a Ford. I bought an ELM device from Amazon and use a free version of Forscan. Anybody that has one of these trucks should be able to afford less than $30 to be able to read all of the codes. You can also read real time data. I've used it to reset parameters on how my daughter's 2018 Flex operates. It's an amazing tool.

The ones that are difficult are the pre-1999 Powerstrokes. They did codes differently than the rest of Ford. With the 1999 Superduty the codes and the ability to read them was brought back into the mainstream.

I don't know how to diagnose these trucks without having the truck here to work on it and without codes.

 

I have forscan as well. I’ve used it on probably 50 vehicles by now. But I haven’t looked to see if they have an adaptor to go to the non obd2 eec4 computer. I’ll be getting one if there is. I did just look up an $8 adaptor to go from ford 7 pin to obd2. I’ll be getting it to see if it works or not. Reviews say it doesn’t work. Some people claim it does.
I’ll give it a try.

 

Justin, the email address isn’t working.
Mine is UNTAMND @ aol. Com

 

Sorry it should be 238 not 248. Fat fingers. I’ll email you tonight thanks

 

I have a E40D transmission the transmission is shifting real hard and the odometer not working & the ABS light is Staying on and the od lights staying on any suggestions 1995 Ford F350 turbo diesel

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Get the codes read. That will give a good place to start.

You can download Forscan free at www.forscan.org. You will need an ELM327 OBD-II adapter to connect it. I bought mine from Amazon for less than $30. Or you could take it to a good independent shop or a Ford dealer. The places that read codes free CANNOT read the codes that you need.

 

just wondering if it ever worked