I have the same problem. You are probably going to have to rebuild the transmission. A scanner would give you a better Idea what is going on with the transmission. I am going to be rebuilding mine in a few weeks.
( god I can't wait) I will keep you informed.
Yeah 2500 ,but what'* weird is, I just drove it a couple miles down the highway and now overdrive is working again?????Is the trans getting hot and not wanting to shift? Any FWD trans tech guys on this board?Fluid does not smell burnt.