Well I looked at a lot of threads that have almost the same problem that I have but I figure I would post this anyways to see if I can get more help. I have a 2004 f150 fx4 5.4 with 132000 miles on it. I had the trans fluid flushed and changed about 2 months ago. Now while accelerating it slips while shifting between 1st and 2nd. Also it slips a little bit while stepping on the gas at around 40 or 50. When I have the radio off and a/c off I can faintly hear a high pitch grinding like noise but it's not loud at all. I'm thinking I'm going to find some metal shavings from that noise. Idk. I'm not a mechanic at all so if anyone can help me out that would be awesome!