Fortunately, I get to reply very quickly.
I contacted GMC, informed them of the issue and requested assistance, they set up a case file and told me they would contact the dealership within 4 days.
I called the dealership, told them I was coming in to get my truck and that I had contacted GM.
The very next morning, the dealership called and had spoken to GM who had agreed, even though I am 437 days out of my bumper to bumper warranty, to pay all but $240 for the repair.
Thank you everyone on here for the advice, it worked out well for me. I will also add that even though I bought my truck elsewhere, I always get good service from the dealer I use.