I have searched but haven't seen my problem discussed.
I have a 2008 screw with the 5.4 and the problem I'm having I am driving slow, like through town at 25 to 35 and am in traffic so I can't go ahead and get up to speed the transmission will slip when it goes to change into high gear.
If I don't have to drive like a granny it has no problem.
Does anyone know what may be the problem?
I have 125000 on it now but it has done it since I inherited the truck at 66000.

 

CEL? has it come on or does it flash while this is happening?

 

No not at all

 

Last time your tranny has been serviced ? Is the fluid level correct ?

 

I had posted earlier but don't think it went through.
I have not serviced the trans., I have an 02 with 240000 on it and it's never been serviced and works perfect.
My fluid is at the proper level

 

No matter what the book says. Tranny fluid is not lifelong fluid. I would start by replacing the fluid, dropping the pan and replacing filter,clean pan and magnet. How you go about fluid change is up to you. You can drop the pan and replace 4.5-5 qts at a time. Or go to ford and have them do it for you. Plenty of write-ups on here to show you how. I would look into this soon.
If you got it at 66k, I'm pretty sure the PO didn't change it.

 

Also, if/when you drop the pan. Look for a plastic plug inside the pan. That'll determine if it's ever been serviced.

 

Did you ever get this resolved or find out what is wrong? I just bought an 08 lariat 5.4l with 84k miles and it started doing this same thing. Only does it when I'm going slow. I looked at the fluid and its a nice color and seems to be at proper level.

 

No I didn't, my fluid looks great, doesn't smell burnt, and it's at proper level.
I'm thinking it's something to do with the programming in the computer but you'll never get a dealer to take care of it until you have paid them a fortune!
Same as you, mine only does it when taking off easy and slow.

 

There is a bulletin out on a tranny re-flash...had mine done for free. it only slipped at around 25-30 MPH.