1995 Ford Explorer transmission cooler line

There is a copper looking line running from the bottom of my radiator back to the tranny. In the line is a piece of flex hose with what looks like the same kind of clamp used on fuel lines. I have a leak right there and I am not sure how to go about fixing it. I believe the fitting requires a certain tool, and I don't know if it can be tightened or if I could make up a piece of hose or purchase one. Any advice would be most appreciated.