I recently purchased a f150 with a reg cab short bed 4.6 4x4, and when you put it in drive the it shiftes up to second fine, but when goes to third just revs up doesnt pull at all. Have to shut o.d. off and goes steady but run 2500 rpms to go 40 mph. I was told to check the solenoids but i dont know, if i do need a new trans how do i identify my trans. I know it has the code "U" on the door sticker, but its an 4r70 w aode-w. But the junk yard has a YL3P-FA and a YL3P-JA? Im not trans expert, so any info is much appriciated.
Thanks- Brad.

 

If there is a faulty solenoid or harness there will be a code set to that effect.
Otherwise there is an internal mechanical fault.
The trans is a 4R70W not an AODE.
Do not try to sub another designation because there are to many differences from year to year, as time went on.
Some of the differences are the plugup, the speed sensing etc.
Good luck.