what legal document can I use to keep the trailer in my name and that makes the other party responsible for repaying the loan.

You can make a contract with someone to pay your loan, but that doesn't relieve you of your obligation to the lender to whom you're responsible. The only thing the contract would do would be to give you something you could use to sue the purchaser if he/she defaults on the payments to you.

A lender will happily accept loan payments from anyone for an obligation; so long as the money is paid on time, the lender doesn't worry too much about where the money is coming from. But if the money stops, the lender will still be coming after you for payment, and you'll be on the hook.

It sounds as if what you want would be a lease-purchase agreement between you and your purchaser. But even before you decide to go that route, there are other things you should consider:

- A lender is unlikely to lend money to someone for a vehicle unless the lender can get a security interest in (put a lien on the title to) the vehicle. If you retain ownership, your purchaser likely won't be able to get financing, since the bank would have no way of taking the vehicle away from a non-owner if there's a payment default. That means you in essence would be the "bank" for the loan.

- Would you require the purchaser to pay for your insurance costs for the trailer along with the regular payments for purchase in the event anything happens to the trailer before the purchase is complete? If the trailer is wrecked or destroyed before the purchase is completed, your purchaser has little incentive to complete the payments, so insurance is a must for you.

- Is the amount the purchaser would pay enough to cover the remaining payments on your loan for the trailer?

- If your purchaser can't get approval from a bank for the purchase, why would you want to do something -- take a risk -- that a commercial lender is unwilling to do?

- Is it possible that you're asking price is too high? Perhaps the reason the purchaser can't get approved for the amount you owe is a too-high price. Just because you owe a certain amount on a vehicle doesn't mean that's the current value. Often, an owner is "upside down" on a vehicle for some period of time, particularly if it's close to the start of the loan term.

If after considering all of this you decide to go ahead with the sale, you should get the advice of an attorney licensed in the jurisdiction where the trailer is located/registered, whether that's NJ or PA.

Of course, as with all of my online answers, my advice is limited by the brevity of your question and the facts provided. Additional information would be required to provide definitive legal advice, so this answer isn't intended to, and does not, create an attorney-client relationship.

Good luck!