You could do a voluntary repossession.
While a repossession never looks good on your credit a voluntary repossession is slightly better.
A good friend of mine had a situation like this about 11 years ago. She was in an accident didn't have replacement coverage insurance and was left with a large chunk of debt on a wrecked vehicle that she then rolled into a new car.
In the end it came down to the simple fact that she could not afford a car loan on a vehicle that never was worth as much as she owed. Since the car was worth less than the loan she really couldn't sell it to fix the problem. She called and arranged a voluntary repossession. She stopped making payments, and parked the car till they came and picked it up. (Took about 4 months and 20 phone calls from her for them to come get it.)
In the mean time, I purchased her a much older used but decent car for a couple thousand and she paid me back over the next year. The total she paid me back was less than the money she would have paid in the 4 months it took them to come get the car. In fact by the time they picked up the car she had paid back over half on the car I bought her.
Yes the repossession did stay on her credit for seven years but during that time she was approved for a mortgage, cellphone plans, and credit cards etc. Therefore I don't know that it did that much damage to her credit.
When her car was sold at auction by the repo company it sold for much less than the loan amount. Technically she was on the hook for the remaining amount. The outstanding balance on the loan was then sold several times to several different collection agencies. Over the years since then she has gotten letters every now and then demanding she pay the amount off, she ignores these. Most of these letters even included very favorable terms (full forgiveness for 20% of the amount) At this point the statute time has run out on the debt so there is no recourse for anyone to collect from her.
The statute time limit varies from state to state. Some states it is as long as 10 years in others it is as short as 3 years. What this means is that counting from the date of the repossession, incurrance of debt, last payment, or agreement to pay whichever is later if the statute period has elapsed and the lender/collector has not filed a suit against you by the end of the period then they have effectively abandoned the debt and cannot collect.
Find out what that period of time is in your state. If you can avoid the collection agencies till that period runs out you are scott free. You just have to make sure that you do not ever send them any money, or agree to pay them anything as this resets the calendar. If you do not want to wait for the calendar to run out if you wait long enough you will probably be offered favorable terms to pay only a fraction of the remaining amount, you just have to wait it out.
Note, I normally would not endorse anyone not paying off their debts. However sometimes it is necessary and it is for this type of situation that we have things like this and bankruptcy.