Math is unemotional. If you can get a zero percent on a balance transfer then do what feels best. Otherwise pay off the credit card asap.

This site is all about long-term thinking. Take the $55/month in interest you are paying on the credit card and think out more than a few months. Once you have paid it off (and it will be less than $55 almost immediately), the long-term savings will snowball.

Honestly, if the car loan is zero percent you should be making the minimum payment and investing the difference (once you have paid off the cc).

Doing a back of the napkin (and assuming you never make another payment on your credit card), assuming an annual 7% return if you were to invest the $16 difference in monthly interest charges, you would save/earn $2956 over ten years by putting the one time cash on your credit card.

Of course, if you pay off the card sooner then you will make even more (and lose much less in interest payments, further building your snowball). If you put your savings into tax advantaged accounts it snowballs even faster.

So, you can put it on your car loan and feel some satisfaction, or you can put it on your credit card and make - at a minimum - $3000 over the next ten years without having to work for it. I don't know what your car payment is, but you should pay the minimum and let it run itself out.

Note - none of that works unless you actually invest the difference.