Vehicle customs, lost passport

My truck and I are US citizens. The truck permit for 6 months in Mexico cost $485. I must be at the border by 6/6 and I'm 8 hours away. The problem is I can't find my passport! What will happen? Can I check the truck out of Mexico without my passport so I don't loose $485? Do I have to leave Mexico or can I get another permit and deal with my lost passport at a consulate and avoid going into the states? What a mess...

Best Answer

OP provided feedback on the experience:

Here's what happened. I went through the steps of 'cancelling' the 6-month vehicle permit, turning in papers and scraping the sticker off the window, as I was returning to the US. The cost was rolled back onto my card. At the US border, I explained to the officer that I couldn't find my passport. With my current driver's license, confirmed by my vehicle registration, and after the dog sniffed his approval, I was welcomed back with a friendly scolding to be more careful with my important papers!