How do you drain oil from high low selector?
If it were me, I'd remove the rear cover and make sure everything inside is nice and clean. It will also allow you to see how everything inside works. The three screws on the bottom hold the bottom bearing in place...
As for protecting the axle housing at the spring perches, I think your sand blasting and painting will provide many decades of added life to it. Remember, it took 60 years to get the way it is now and that's with no one caring for it! Don't overthink it...
Mike B
