Has anyone found a fix for this problem? The dealer had the gearbox rebuilt under warranty, but the problem still exists. The diagnostic computer does not see the problem and test drives by the dealer have not replicated it (happens maybe once a week or so). This problem does go away in winter mode (at the recommendation of MB Technician) but I do not consider this a "fix". Can anyone tell me what controls automatic downshifting? Is it a computer module or control valve system? Is it time for a trade-in?