2004 Fx4 115,000 mi. 5.4 I noticed recently that when I stomp on it to pass someone it downshifts fine but wants to stay in that gear and the rpm's just keep climbing until I let off of the gas. It seems to keep climbing until it will redline so I let off and then it shifts back up and is ok after that. No slipping or bucking. Its not the normal type shifting Of gears when passing or climbing hills etc. It really starts to scream if I don't let off. All fluid levels are good and have been changed within the last yr meaning trans, diffs. It otherwise shifts normal upon normal acceleration

 

sounds normal to me, keep in mind we have a 4 speed trans. Keep the gas mashed it should shift at close to redline, are you letting it get that high??? I think the truck has a limiter so if it really is your trans the RPM will just stop at the redline and you won't shift up, is this what is happening?

When you floor it the truck wants to stay in the lowest gear and close to the power band which is close to redline(not sure what the peak hp rpm is, I'm guessing it's up there)

During normal driving it will shift much sooner for economy.

 

I'm not letting it get that high but it didn't used to do what it is doing now. It used to shift sooner even on hills and passing someone. Yes the rpms go higher than normal driving but it would always shift back up even if I kept on the gas. It seems as if its not going to shift but just keeps climbing in rpms so I have to let off the gas or it will just keep screaming and getting higher and higher. Been driving this truck long enough to know somethings not right, not trying to contradict you. I thought maybe it was the TPS or something acting up. Don't know enough about trannys to make a guess with that. Anyway thanks and I'll keep an eye on it.

 

I believe the PCM determines the shift points (my edge programmer lets me change them). I'm by no means in expert in this, maybe unplug the battery and reset the PCM????

 

just wanted to say thank you. I was sitting on the side of the road thinking I was stranded and this trick helped me get home. So thank you, I appreciate the help.