15 Dec 2014 When the amount you owe on the car is less than the trade-in value, the process is pretty straightforward. Say you still owe $5,000 on a car, and Sometimes you want a new car before your current car is paid off. If you put less than 20% down on your vehicle, this is very likely to happen to you within the first year. will owe the full remaining value of your loan as soon as you trade in your vehicle for a new one. How Do You Sell a Car You Still Owe Money On?