So difficult to form a firm conclusion on the strength of the oil colour, it does look like migrated engine oil with the hue of combustion, but it could just as easily be the detergent in a newly changed oil doing a clean up job of the internals of your primary chain case, but my feeling is it is simply migrated engine oil, fairly common, especially if the engine has heavily wet sumped, none of which explains the glitter in the gearbox, that could be a fairly big problem, you might need the help of an expert, sadly they are getting thin on the ground these days.