Strange thing happened to my 2000, 350 dually, Transmission would shift into 2nd and then start slipping. 3rd and 4th also felt strange. Noticed that the temp was running way above normal for around town. Checked fluid level and found it OK. Called Ford to find out worst case repair, shocked th heck out of me. Anway took truck to trans shop today, no slippage on way to shop. Got a call a few minute ago, shop can't find anything wrong, no codes, nothing.
Any suggestions?

 

try changing the fluid.

 

Same thing is happening with mine, I know the T/C is slipping but it will not slip and it will not shudder when we take it for a drive. In the end, because I know that the T/C is taking a dump, I am having a new T/C and Shift kit and a few other mods done as well, total set back is going to be about 1500.00.

 

Yea sure sounds like the T/C slipping to me.... I think the tranny does all kinds of other stuff when it senses the t/c slipping - to protect itself from burning up... sounds like limp mode maybe?? But I would think you would have some kind of codes stored!?

 

Mine used to do the same thing randomly and i found that if I unhooked the batteries for a little while and then hook them back up that it would clear up what ever was causing it. I took it to Ford and 2 or 3 other tranny shops and nobody ever could tell me what was causing it. I finally took it to Kenny Burns in Mesa AZ and he told me what it was right off and said that it was some pressure valve that was worn out in the tranny. Well I had him do a total rebuild with all new sonnax valve and transgo valve body, triple plate converter and the whole 9 yards. And he showed me the bad valve that was the original problem and it was worn out. Only set me back just over 3k, but talk about the difference of power transfer to the ground!

 

Sound like my truck started slipping & acting up took it to ford put it on the machine no codes, they test drove it they couldnt find anything. The trans oil wasn't burnt but had a electrical burn smell to it. They flushed the trans out and I picked it up, the next day I was going into town I didnt make it half way the tranny was slipping and then stuck in 1st gear. Took it back to ford, tranny shot replaced it with new one in the process now of changing ring & pinion gears to take care of the strain on my new tranny