Refinancing an auto loan can start your loan from scratch, but it's not necessary. Refinancing can also qualify you for a higher interest rate, which translates to a lower monthly payment. Refinancing exchanges your current loan for a new one. You could get a lower interest rate and a shorter or longer term than you currently have.
However, opting for a longer repayment period for a new loan could make you feel like you're starting from scratch. Usually, the first payment on your new loan is due 30 days after you've formally accepted the loan. Make sure you know when this payment is due and that you do so on time to avoid commissions or charges. Since refinancing involves applying for a new loan with new conditions, you basically start from the beginning.
However, you don't have to choose a term based on the term of your original loan or the remaining repayment period. For example, if you're refinancing your mortgage, you might find that the top mortgage refinancing lenders offer several repayment terms, including 10, 15, and 30-year terms.