I don't have a 59, but it should be at a point that is at least as high as the top of one of the axle tubes. It may have a kind of loose cap on it or it may have a hose going up to the frame and then have a kinda loose cap on it. I guess it could even be on the top of the diff housing, but that would be a new on on me. If you see none of the above...make sure it isn't missing. Make sure there isn't an open hole on the top of one of the axle tubes.
Larry W.
