I apologize if this is the wrong section, mods.
Anyways, my transmission has been acting up over the last few days. I was cruising down I-26 at roughly 75-80mph when my over drive light started blinking. I pulled over, shut off the truck, started it again, and slowly accelerated. It shifted smoothly as normal, I kept driving. The light started blinking again after I had driven 30 or so miles. I pulled over again, shut if off, and started again. Once again, the light didn't blink until I had driven quite a ways. I parked the truck overnight, and decided to take it into town this morning. I drove 75 miles, and the light did not come on a single time. However, the transmission shifted at the most random rpm's, and wouldn't stay in 4th gear unless I was going at least 70mph, where it usually shifts into 4th at about 60mph. Like the day before, it shifted smoothly, and all 4 gears pulled correctly, it just won't stay in 4th when it should.
Hopefully that was all understandable... ideas?