I did get the Diesel Exhaust Fluid (DEF) swapped out in the tractor. The warning lamp is still lit, but I expect that once what little fluid remaining in the transfer line clears out that it will go blank.
What seemed like a simple, straight forward, ‘remove plug, drain fluid, refill tank’ task turned tricky when the owner’s manual proved to be too big of a task for the manuals author. He has obviously never looked at the undercarriage of this model New Holland or he would have seen that the only drain plug visible is that for the fuel tank. Oh, by the way, the diagram for draining the fuel and that for draining the DEF are exactly the same diagram, and it is wrong for both.
Again, if he had ever looked at the undercarriage he would have seen the large heavy skid plate that covers both tanks. So, after removing the skid plate that runs along the bottom of the tractor and trying a gazillion allen wrenches until I found that an 11/32 inch wrench is the right size (which is bullshit all into itself), I was able to get it done.
I’m back in business and eager to put the brush-hog back to work.