My problem is a metallic rattle that I hear only when accelerating, and even then when pushing it a little 'extra'. Noise not present except when in D and leaving a stop. Otherwise car is fine, ie no loss of power or shift problems.

The closest thing I have ever heard to this is in a Std car I had (VW) If mistakenly you started from a stop in 3rd, the tranny or clutch struggled and rattled until speed was sufficient for that gear, if that helps...

Any thoughts?