i have the same truck thats the lower rad hose their was a update but the cost of that hose was around 350-400 and the o-rings were around 15 for both ends if it's anitfreeze you are leaking
Yes it is the lower rad hose and it is an expensive hose, ford changed mine this summer on a 09 350 but I do not remember it being $400, I think it was less. I think you need a special tool to change it, but I am not sure.
there is a updated upper and lower that use two o-rings instead of one. take a look at where the upper attaches to the t-stat housing, the upper will leak and drip down on to the lower, that or the lower leaks at the motor connection. you may get lucky just changing the o-rings but how long it last i dont know.