I've noticed between 25-30mph my truck shifts kind of hard. I have no idea why it would do that but it's been fairly consitant since I bought it in August. But only at that speed so I guess that would be 2nd to 3rd?

 

So, the more I've been paying attention to it, it feels like it's slipping. Any thoughts??

 

What year, engine, transmission, and how many miles on it? Have you ever done a tranny fluid replacement?

 

MY 1999, F150 Automatic with 134,000 miles is starting to do that same thing. I was just told that there was a vacuum hose that goes into the tranny that is leaking. I don't know if that is hard to replace or if I should do it myself if I can. I certainly would rather do it myself at this point.... $$$ ya know? Anyone have advice about both, in case the one is actually leading to the other?

And I just did a partial tranmission fluid replacement as opposed to the entire flush of the system before I realized that is something that I really need to do instead.

 

These transmissions are not at all vacuum controlled, so there isn't any vaccum source to them like on much older transmissions.

If the rest of the transmission is in good condition you can get an aftermarket valve body kit like the one from Troyer Performance and it will likely straighten out a lot of shifting issues. The kit isn't too agressive and will actually add life to your transmission. And, it's a cheap enough do it yourself alternative to boot.

As long as the transmission is in good shape otherwise. Don't forget that part.

Darrin

 

It is a 2008 FX4 5.4L with about 3,000 miles so I wouldn't think there would be a problem already. Maybe it's just the way the shift points are in these??

 

Go see the dealer. Your truck is on warranty.