Thats the key, the bank would have given a few pages of fine print telling the penalties for turning the vehicle back in early. There would have been an amortization schedule telling how much is owed each month and that if they take the vehicle back it will be sold at auction and the loane will still be responsible for the difference.
I looked at this a while back when I got laid off. I found a new job but health insurance tripled in price so I was looking at how to reduce debt. I found I was better off keeping the vehicle/loan rather than trying to sell it and having to come up with the difference because a shorter term unsecured loan would end up having about the same payment per month.
I gathered up anything I could find that I could live without and ebay'ed it and got enough to pay off a couple of my school loans, then found a very part time job with a computer consulting company where they would call me on occasion to cover when they had too many jobs for their normal employees so it was just a small job or two a month but gave me about $150-200 a month that I could throw at my other school loans and I ended up paying them off every month or two until that $200 a month bill was gone then started on the smaller credit cards.