Leaking axle seal 8 3/4

Hey quick question for some of you guys, I know this thread is kind of old, but who cares. I've had a leaky passenger side for a while now, I've replaced the seals twice and had a local machine shop try to fix the groove in the axle where the seal is, but it hasn't seemed to help.

Where can I get one of these axle sleeves y'all were talking about? I've never even heard of one. Also If the sleeve doesn't solve the issue, where can I get a new axle shaft? The only place I've seen that carries them is classic industries. Would I have to replace both shafts if I did this? FYI this is for my e-body! Thanks for the advice guys!