I need help with my rear

I think yur jumping the gun.
I have never heard a diff make all those sounds. And I don't know of anything else back there that could, unless it's in the brake housings; they can groan when yur riding the brake-pedal. And I have heard noises coming from the backing plates, created by the shoes.
So maybe have a look in there first.
I have heard U-joints groan too.
After that I guess,I'd drop the diff and see what's what.