Gene,
ALL you have to worry about is warranty.
With what you said re up to 14000 have, you're legal if pulled over to 14000 on your two axles.
As far as legal gcw goes, again, legal us max your registered for. Probably upwards of 80,000 lbs. Assuming you have enough axles etc under you to carry the weight from the road bed engineer specs.
But, if you blow your tranny up at 20k miles, doing 80k lbs, ford will deny warranty as you're over 18000 gcw.
Yes, I've been pulled over at 150%of manufactures ratings, I have YET to get an aver weight ticket, as I've always been under registered weight/tax paid for damage I'm doing to roads at that weight! That's ALL an leo/cveo cares about from a weight perspective.
I have had warranty denied due to above and beyond GM spec for what should or could have been under warranty.
Marty