1999 2500 4x4 Quad cab Diesel automatic, 90k miles, all stock. Noticed today pulling empty enclosed car trailer that it seems the tranny is slipping ( I know these are notorious ). Could it also be the throttle position sensor instead? It seemed like with it hardly being under load the tach seemed to be going all over. I did unhook the trailer and took it out tonight and wasn't hardly noticable. Am I crazy thinking/hoping it is just the sensor? Didn't scan it, but dash showing no idiot lights or faults. Tranny flushed/filter change less than 10k ago. Pulled the trailer about 25 miles today, no burning or hot smell.