A friend of mine here at work owns an early 90's Chevy pickup truck. He let his brother borrow it for a few days. Being the kind brother he is, he noticed the tranny fluid was quite low and added several quarts of "Type F" fluid (obviously the truck had Dexron in it). My friend knows I am an oil geek, and came to me for advice. What are the risks of leaving it in there? I told him to drain and refill, but he is more than likely going to just leave it, as it "doesn't feel any different". Can you guys shed some more light on this?