I hear knock and ping feel a spin or vibrations when i plane out in overdrive on 1992 Pontiac Bonneville

1992 Pontiac Bonn. have always driven in gear OD. stills shifts nice.! recently serviced feeling something at my feet and hear (with windows open) knocks/pings. no hesitation. no jerkin. is OD gear going out... that possible? or the whole tranny. can just one gear be fixed

Asked by for the 1992 Pontiac Bonneville