The loan balance is immaterial on an income tax return which is why you are not prompted for that information.
You sold the car to the insurance company and bought another car ... just that simple. Trading in a vehicle is no longer reported on an income tax return starting with 2018.
The cost of the vehicle becomes the basis for depreciation and you can only deduct the business portion. Work thru the sale in the vehicle expenses section slowly and let the program do the work for you. If you need more guidance then either upgrade to the LIVE option or call TT support.
