Not sure what you mean. Most (as in 99.9%+) auto loans have no prepayment penalties, so you can usually trade right away/pay off the loan immediately after it funds.
You might be underwater in which case the underwater part will have to be either rolled into the new loan or you'd have to come up with it in cash. What's the KBB Good Trade-In Value for your car and how much do you currently owe on the loan?
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