Rear end pinion noise

Recently replaced the front seal and fliud with additive and it drives nice with all the other suspension items i completed. One thing that is not right; at speed greater than 45 when i let off the throttle the rear end has a noise. My guess is the preload on the pinion is not correct. The rear end was replaced by GM after a bolt came loose and it exploded. Looking for other opinions.

--Eric

Thanks Ken.
Got it tightened up. All that I can say is thank goodness for 3/4 drive tools. Now once I get my rebuilt carb back, I can go for a test drive.

--Eric

I could be preload, or it could be a bad wear pattern between the ring and pinion. Did it make the noise before replacing the pinion seal?

I'm not sure if it did or not. The brake calipers were leaking so bad I could not drive it. I did mark the pinion, yoke and nut before I took it all apart and I could only tighten the nut within 1/3 of an inch of where it previously was set since I don't have the special tools.

--Eric

That 1/3 of an inch makes a big difference. Rear end set up is VERY picky. Do what ever you need to do and tighten it that last little bit. Otherwise you could ruin the diff. Yes, that much can make a huge difference. Don't drive it more than necessary before you get it tightened. You could damage the ring and pinion and create everlasting noise.