IF you throughly clean the BG sleeve & the carrier splines, you can loctite the sleeve in place, it's not gonna go anywhere. There is an inner & outer seal, so with the sleeve in place, no debris can get inside the diff.

A VS'er who used an M66 in a FWD configuration added a modified CV boot to cap the whole thing, but I don't think that is really necessary, albeit not a bad idea.