Benson purchased a new Ford Thunderbird automobile. She traded in her old automobile and financed the balance of $4,326 through the Magnavox Employees Credit Union, which took a security interest in the Thunderbird. Several months later, the Thunderbird was involved in two accidents and sustained major damage. It was taken to ACM for repairs, which took seven months and resulted in charges of $2,139.54. Benson was unable to pay the charges, and ACM claimed a garageman's lien. Does Magnavox Credit Union's lien or ACM's lien have priority?