i put on new gasket i put ultra black rtv on both side of gasket and on each bolt when screwed in and still leaking any ideas

 

you didnt put enough RTV on it then. do it again and cover it in RTV

 

leave out the gasket. and make sure both surfaces are clean and void of any existing rtv and/or gasket.
use a good thick bead of rtv, you only need it on one surface. go around the holes. and don't worry about what ends up inside the diff, the gears will chew that up no problem.
just leave it a few minutes before you put the cover on. then another 15-20 minutes before you fill it back up.

i like ultra black by permatex.

 

get a new gasket. clean all the surfaces really good.make sure there is no oil still dripping out of diff. put a small bead in he diff and the cover. replace the gasket when you reinstall dont over tighten it. i only use about 20 to 30 lbs. fill it and see if it leaks.

 

see i took it off scraped it clean and used a wire brush on it and brake cleanered it make sure it was off did a thick bead inside then gasket and then bead and then cover and each bolt i put rtv on them so idk what the hell

 

that's weird, there's no rust holes or anything in the diff cover is there?
i'd remove all rtv and clean it up and try it again.
just be sure to leave it sit for a bit to cure the rtv before you fill with 75w90 gear oil.
if you have lsd clutches, be sure to add friction modifier.

 

it could be a pinion seal....

 

I'd be willing to bet at some point the diff cover has been over tightened and the surface of the cover that mates with the diff case is deformed due to over tightening. Straighten the cover mounting surface, apply a thin coat of rtv to the clean case and around holes, stick the gasket to the case, apply a thin coat of rtv to the clean cover and around holes and install. DON"T crank the cover bolts down hard, just snug is plenty good. Don't want to deform the cover, or crush the gasket or squeeze too much rtv out.

After changing the gear oil, if the LSD diff is quiet (no noise/chatter) in a turn, you don't need the additive. The additive makes the clutches slip easier, so they're quieter in a turn, wear quicker because they slip easier and more often, which will make a LSD diff perform more like an open diff sooner because the clutches have worn out from slipping.

 

see idk everyone telling me not use a gasket idk

 

you don't necessarily need a gasket if you are using rtv. i've never used a diff gasket.
so, as mentioned, you may have a bent or dented diff cover, or your pinion seal is leaking.

can you see where the leak is coming from? is it coming from the plug, diff cover, axle seal or pinion seal?

post a pic...