U joints? Differential? Help please.

So I am having a problem. Every gear I hear a loud screeching sound from the rear end. Sometimes it even pops. It only happens when the truck is on the ground because i had it up on jackstands and had it in gear. Tried every gear and heard nothing but as soon as there is weight on it, it sounds absolutely horrible. I figured i'd turn to you guys first before trying to problem solve. The driveline is straight and doesnt wiggle around or anything. Help asap please this is my daily driver.

Any oil visible from the rear end?

No, but I did just drain the oil and found metal shavings. So i'm going to take the diff cover off tomorrow and check to see whats going on.

If it's 86 to 93, there isn't a cover. You have to pull the axles and third member.

Well looks like i am doing that.