I have a 99 7.3 f250 with 99000 miles. Everything was great until today. I was towing a 79 cadillac on a trailer and I noticed my transmission wasn't shifting as usual. When I took the load off and drove around town the transmission would not shift into 3rd gear. I shifts into 2nd firmly and never got hot on the guage. I checked my fluid and it was full but did smell odd. Also, I tow a load maybe once a week on average and nothing too heavy....under 10,000lbs. I do have my truck chipped with propane but generally I never drive over 35mph. If I get on it, its usually to pass someone on the highway. Any help would be appreciated.
Thank You

 

I think you may have the same problem I had, but I need a few more details. Do you have to back off on the throttle to get it to shift or is it stuck in a specific gear?

 

No, its not stuck in a gear but once it gets into 2nd it will not go up to third. I will go back down to 1st.

 

I've the same model w/250,000, and its doing kinda the same thing, but it doesnt do it all the time, and I havnt been able to pinpoint at what rpm. It gets up to 2nd, and then feels like it shifts to 3rd, then back down to 2nd within a second, and then gets back to 3rd, and stays there. But like I said its pretty sparatic, it seems it only does it when the throttle is some where in the mid range. if you floor it, or take it really easy it works just fine?

 

Welcome to FTE.

I'm sure the OP has this fixed by now. It's been 4 years he had that problem.

We need more info on your truck and what is going on with it.

 

Holy old threads Batman!

My best educated guess is that you're low on fluid. My trans did a few things like delayed shifts and shifting harsh and after I added 2 quarts, things really evened out....

 

May be time for a transmission flush?


Changing ATF Fluid in a E4OD and 4R100 transmission .: Articles



I flushed mine out a few months back, but it was already shot.... soooo.... The Wife let me get a new BTS-Trans.