FICO has a category, which accounts for 30% of your total FICO score, that looks at utlization of credit.
Under this 30% category, by far the highest weight is given to your risk of payment of your revolving (discretionary) credit.
Weight is also given to your utilization of installment (fixed balance) credit, but at a much lower weighting.
The reasons are intuitively simple. Lets say you open a new installment loan. Almost always, by definition, it will start at 100% util of the loan. If you qualified for the loan, that shows good credit. Having a high principal balnce on an installment loan is expected, and not really negative.
Thhus, 100% util on an installment loan is not a good indictor of your risk or repayment, which is what FICO is. Additionally, most installment loans are secured by personal or real property, making the risk of nonpayment even lower.
However, if you have a revolving line of credit and use it up to 100% utilization, that is an indicator of serious risk, an will hit your FICO score big time.
Paying off an auto loan early is more of a financial consideration (avoidance of interst) than a FICO consideration. FICO rewards you for long payment history in another category of FICO scoring, that being avg. age of accounts. Paying off an auto loan does not delte the account from your CR, and thus it still counts in your AAoA calculation. Having a long period of timely payements is "rewarded" in your payment history portion of FICO scoring, which is 35% of your FICO score, not by inclusion of timely payments, but by the lack of delinquent payements. Drogs are scored, lack of derogs are expected.
Thus, I would not expect much of a FICO gain by early payment of the auto loan.
