When I did my 46,same construction,one side was tight the other one rivet was broken. As you say no way to replace the rivet. I welded the broken side to the axel. I also had the two 1/2 shells machined to reduce the clearence. I had allot of axel wear. Other than an oil mess and having to check diff fluid I don,t think there an issue. That rivets might fail someday? You might be able to clean the parts and force rtv between to reduce the leakage?
