My 2005 f150 is having transmission problems. It doesn't go into gear when I put it in drive, and I am pretty certain it was slipping while I was on the highway. The overdrive off light flashed a few times while on the highway also. Can anyone give me a clue where to start, I have not checked the obd yet.

 

Are you able to check the fluid level on that model year? or is the trans a sealed unit.

 

I did check it, it appears full.