I finally started my '41 GMC on Friday after sitting for three years. After unsticking the float needle, all is fine. I drove it about ten miles and turned around on as asphalt driveway. One rear tire dropped off the pavement about 6 inches. When I eased forward, I heard a terrible popping sound. I stopped immediately and looked underneath. Seeing nothing out of the ordinary, I inched it forward again...and still had the popping sound. I put it in reverse and it did not pop. After several forward and backward moves, it made one popping sound and I felt whatever was in a bind free up. It has given me no problems since. Does anyone have any idea what might have been going on? Thanks, Jim.