Consolidated 25,000$ of debt on a loan,8.6% 516.00 mth made 33 of 60 payments,c.card offering 3.9%untilpaid?

would i save money to transfer my loan balance$13.000 at 8.6% fixed that i have thur a bank loan, at 516.00 a mth, already made 33 of 60 payments, my union plus credit card is offering me 3.9% for transfer,for life of loan, would this be a smart move!i would only use it for this loan! is the calculation on loans and credit card different?