380SL Blue Smoke

Is there any plausible reason why my '82 380SL emits some blue smoke in "D" at idle on the roadway and emits the little more blue smoke on take-off - and then disappears - (which seems indicative of worn seals or guides) - but refuses to do the same thing idling in "P" or "N" in my driveway. No smoke at all at idele or when giving it some gas.

Could there be some weird vacuum issue happening? The cam oilers are firmly in place, the valve cover gaskets are fresh, and the crankcase ventilation hoses are OK and are properly attached. It is definitely motor oil and not transmission fluid.