Well I was on my way up elk hunting this last weekend and I was pulling my trailer over Mount Hood. It was about 90 degrees outside and after I got over the pass my transmission started making a grinding type noise. The tranny temp was at about 200-210 degrees which is pretty high considering my tranny temp gauge usually always reads about 180 to 190 after a good pull no matter what the conditions are. Anyway once I was on my way back down the other side of the pass my tranny started shifting in and out from third to fourth non stop so I figured maybe KDP, then all of a sudden the tranny automatically downshifted into second gear while I was cruising along at about 50mph. I had my foot on the pedal at a constant speed the whole time while this all happened. When I truck went into second it would not shift after that at all. I pulled into a parking lot and tried to get it to down shift into first, and tried to get it to shift up into third and it just rtemained stuck in second gear. What do you guys think the problem is. Am I looking at rebuilding a tranny?