Noise from a 3.55 gear 8.75

I have a stock 3.55 cone type 8.75. I get a slight hum on decel. The pattern looks beautiful on both sides of the tooth. Tried different weight oils. It's quiet under acceleration. Doesn't matter if you are turning or straight. Should I just rock on and see? Tried to take pics but the lighting was bad and the flash hid the paste pattern. Is it possible it's just a noisy mate of the two gears? This chunk has never been apart. Came from a wrecked A-100 I believe. Been a while since I pulled it.