Fly Z28

1995 Formula convert. with 6speed and the posi rear, 3.42. Car is stock except for cat back exhaust and K/N filter. Bought it at 78000 miles, 112000 now. Pretty clean, looks to have always been a driver, no track. I serviced the diff. last week, used Mobil 1 LS synthetic fluid-2 quarts and a bottle of the AC Delco diff additive. Can hear very minor sound of rear end with radio off especially when slowing. Never tried to listen for it before, may have been there always. May be easier to hear with the cloth top?
I guess my main question is-did I used the right stuff? If it is the right fluids then should I just drive it unless/untill it gets louder?? Am I being overly paranoid. Love this car and dont want to f it up.
Thanks, Bret

rv93

what weight oil did you use? also, was the car level when you filled it? you have to fill it until oil starts running out of of the filler hole.