Thanks that is what is used. When I bought mine years ago, the threads of the fill/drain plugs certainly didn't feel right coming out or going back in. No leaks, so I kind of forgot about it. Just did my diffs and tc again, and I it looks like I have a small leak in one or both plugs. Anyone have any recommendations outside of retapping etc? Initially, I don't like the idea of any thread sealant or teflon tape. Thoughts?