I have an 05 Ram 2500 5.9l Diesel with a 48RE auto tranny. I'm moving from CO to TX and have made a few trips moving personal items with no issues. I got back from a trip a couple days ago and heard a destinctive high pitch whine as I was driving. The pitch would increase as more demand was put on the engine but shifting was normal. Yesterday I was headed to town and now the tranny will not shift out of 1st. It acts as if it is in limp mode. I've reved up to 2000 rpm and let off and still no shift. ODII check and no codes. Fluid is full and not burnt (smell or color).

It did shift after another try at about 2000 rpm and immediately shifted back to 1st. Another attempt it shifted and went thru 2nd, 3rd and 4th but once back to 1st it will not shift at all now.

I've rebuilt several 48RE's but not real smart on component functions. My gut feeling is I may have a front servo issue but before I start chasing a ghost I thought I'd check with more expeienced folks on this matter. Any help on what to test, try, or look for would be greatly appreciated. More trips to TX needed soon. Thanks in advance.