Prior to removing the final drive from my 1984 R80 G/S I put together a list of necessary parts for the reinstallation. I had (mistakenly) assumed that like all other shaft driven airheads that there would be a gasket between the final drive and swingarm flange. Incidentally and for a reason unknown to me, there is not. The factory manual however indicates that "Loctite 638" is instead used to prepare these surfaces prior to assembly but this recommendation is now 40 years old and I'm wondering if this is still the standard "best practice." I don't have a bottle of 638 on the shelf so before I get one on order, is that what the group suggests?