Fixing Axle Leak

1970 Duster project, rear axle is a 741 case 8-3/4"

It appears to be leaking diff fluid where the third member is bolted up to the axle housing

I have never messed around with fixing this type of leak

I assume I remove the driveshaft and then unbolt the third member?

The third member just "falls out" or will it be held in place?

Clean the housing the install a new gasket or RTV?

What type of fluid goes back in?

Thanks for any and all info