Dirty Filter? Or low on fluid? Interesting to see what happened. Keep us updated and good luck!Coming home last night my check engine light popped on. I has slowwing down entering a town when the truck made a really hard down shift. I refueled and got back on the road, as we were accelerating every gear it shifted to was going way into2500 the shifting hard. It did this until I made highway speed. I came to a hill with cruise on and all he'll broke loose. The needle it 3500 back to 2500 down to 1500 and then stuck in 4th gear. I pulled over and shut her down. I got going again and the same thing happened two times on the way home. Real stressful.