Usually shifting slightly past redline (say, 100 or 200 rpm above) isn't that big of a deal if it happens every once in a while. But if you shifted 500 or more rpm above redline, then that might be a problem. Where did the pop come from? Sometimes in modified cars with turbos, they "pop" at high rpms when flames shoot out of the tailpipes, so perhaps pushing the car that much made your car do that.