AT shift problems

Hi I have a 98 F150 with a 4.6l with 90,000Kms. The problem is that when the trans is cool, it doesn't shift right and the OD indicator on the shifter start flashing. Once the trans. is warmed up the problem is still there but is much less noticable and sometimes the OD indicator doesn't come on. I took it to a trans mechanic but they said that they would have to open it and see. The fluid seems ok. Anyone seen or heard about that problem before? Thank for any help :)

You first need to pull any caodes from the computer, your trans is computer controlled (it's a 4R70W most likely).

This can be caused by the "TFT" sensor being bad, simple and rather in-expensive. But you need to pull the codes FIRST, andfind out what they are. You "trans mechanic" should have told you this. Take it elsewhere.

Autozone can pull the codes for ya.