When I was in high school I had a friend that had a 1960 190D. It had a bad starter so he frequently jump started it when on a hill. One day he accidently put it in reverse instead of 1st gear. Well it started !! Ran rough and blew smoke out of the Air intake. The real clue came when he put it in first gear and it lurched backward. I dont think the newer ones will run backwards !