Something to think of, based on your description of smoking downhill only. When going downhill, foot off the throttle, the engine is pulling great vacuum. A transmission modulator going south might only be leaking ATF under great vacuum. A little ATF will smoke a lot.
Just a guess.
As for a little oil on the floor, replacing the valve cover gaskets could cure that. Leaky valve cover gaskets can lose a couple quarts between oil changes.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
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