An oil resistant sealant as mentioned by Ed, will get you by until the end of the riding season , or possibly put some Teflon tape on the plug threads and see if it will help the situation. Unfortunately, I don't think you have too many alternatives, other than disassembling the rear drive, and having it re-threaded for an oversize plug. A trick that I have been using for quite a while, is to use a 'palm' ratchet, and tighten it with your non-dominant hand, and it will prevent over tightening. Keep us informed on what you have done for this problem, if you find away to do it yourself, or a source for parts etc., as this is something that comes up on occasion. Another member here ( tagordon) posted about a company :www.timesert.com, and they have a thread repair system that appears to be superior to heli-coil. I just checked on prices for a Timesert repair kit, and it looks like around $70-80 US, the comment was also made that if you use a heavy grease on the drill bit and tap, and use a shop vac while drilling and tapping the hole, it can be done without disassembling the part you are working on.
