I just purchased this boat as a "not running" project. It's a 72 mercruiser with the rare merctrans II transmission on the inside of the transom, mounted to the 302 ford engine. After checking all of the oil, fluid, and greasing the fittings and getting the engine started, i noticed a rattle or chatter noise in the upper drive. I took the drive unit out to check alignment and found that this drive does not align like most of the mercruisers; the 63-73's do not have the same type gimble housing and bearing to align with than later models. Outside of a possible mis alignment; anyone know what may cause this?