trans seems to be slipping every once and a while i really wanna get rid of the stock trans cooler and upgrade. what set up would you guys recommend and have had luck with? i don't tow much, and when i do its usually not heavy. except for the other day. loaded up about 8000 pounds of Railroad track onto a trailer that probably weighed a ton. truck didn't like it at all. it was pretty bad, going up semi-steep hills i couldn't go past ten mph or even up shift!

thanks guys, brian.