Don't think you can plate the inside because of clearance between the gears. Even if you do plate it you run the risk of it rusting faster and leaking worse or worse case scenerio is the diff breaking off and getting into the gears. But then it again it all depends on how bad the rust is or you have just developed a pin hole and it can be spot welded. There is no real way of telling until you get your diff cleaned up and futhermore you axle tore down to look at the inside. But like said before we are here and your axle is there.I will get pics tomorrow. for everyone trying to help me i thank you. do you think if i check the fluid constantly and top off i should be ok for a while? or worst case can the rear be taken out and the inside plated to stop the leak?