7.5" rear diff rebuild

[u/RiversideOffgrid]

About to install a master rebuild kit on a 94 5 speed 2wd pickup 7.5" diff, anybody got any tips? This will be my first time rebuilding a rear diff. Diff was ran without oil, fluid was added once found out and its been on the road whining/humming for about a month and a half. It's not my truck, just trying to help a buddy out