You can get a puller faily cheap at the flaps, too. You might need to use an impact to get the nut off. Most likely the socket needed will have to be a 3/4" drive, too. Seems that sockets that size are hard to come by in 1/2" drive without going to Snap-On. Get the socket and a 1/2 to 3/4 adapter, Tractor Supply or other farm store will be cheapest. Follow denny's suggestion and soak it. I like B'Laster myself, but I've heard good things about Kroil, too. And DO NOT try to ruch things. Go easy. Trying to rush it and get it off fast will just lead to tool failure. Let the tool do the work for you.
After that, it's just a matter of 3 bolts and the box will come off.
