You need to discover the amortization schedule for the car loan. If you accelerate repayment of your car loan, you may not reduce the amount of interest paid.
Some car loans are similar to a mortgage, in which case, the PP post describing how you can pay it off sooner and save interest is accurate.
Some car loans adhere to the rule of 7/8s, which is how my mother described it, I'm not sure what that means. But I can describe what the effect is. Basically, the interest for your loan is calculated at inception and the pay back schedule is figured out, just like a mortgage. However, should you request a payoff amount, you will be paying off the same amount that you would have paid off, had you simply continued with the original payment schedule. You will not save any interest, and the financing entity will not lose any interest in an early payoff. It is the reason why so many car loans can be written at low interest rate financing, because the financer is guaranteed to get all their interest regardless of payback schedule.
On the other hand, paying down the balance on a credit card can save you a significant amount of interest because finance charges are calculated monthly based on remaining balance.
If your car loan is written to adhere to the rule of 7/8s, then paying it off early will not save you any money. You should pay off the credit card first. If it isn't written that way, and interest is calculated monthly, then paying if off first will save you more in interest than paying off the credit card.