99 Ram V-10 Transmission Problems

So as some of you may know I purchased a 99 Ram 2500 V-10 4x4 QC Auto Trans online back in the beginning of Dec. Well it was running great until I figured out that the trans would stay in 3rd gear and not shift down to 2nd so I only have R,2,and 3rd gears. The truck would take off in 3rd unless you manually shift it into 2nd yourself. Sometimes it would shift like it should and then once it got to overdrive just down shift to 3rd and stay there. If I pull over and shut it off then fire it back up it may shift fine up through the gears then shift back down to third. I am not getting any codes. I just changed the trans fluid along with the filter and solenoid and governor pressure sensor and still same deal. Does any one know what else it could be? I need to get this fixed before I go to school for 2 months and leave my wife with this truck.
Author: lilhatchet