just like on the IDI's... loose the bolts that hold the rear header in place. then yank the cooler out - leaving the front header still in place. the take out the front header...
on reinstall... install front header then slip in the rear header and tube assembly and use a block of wood and pry bar and install tube into header. Bolt rear header to engine.
I know this sounds so simple but it's really not that bad. I always used at bar clamp to install the tube into the rear header outside of the truck. You can use a floor jack and the rear bumper as well. I have done that once...