I don't know why it works that way, it just does. I have the same thin gin my '74. I had to work on my front drive shaft and I had to lock it into 4 HI before it would move. If I didn't, it would make all kinds of bad noises /forums/images/icons/tongue.gif . I ran it that way for a week. It didn't seem to hurt it, but I wouldn't make a habit of it. I am waiting till I can afford a 205 so I can do the doubler /forums/images/icons/smile.gif .