no water in sight glass

Just recently there was water coming out the top of my Vari-Flo Multi Port Valve whenever I turned the handle. When I pushed the handle down the sight glass would fill with water but after just a few seconds it would drain out. The sight glass fills with water when I backwash, but at the normal "filter" position it drains out. I also hear what sounds like ratteling inside the valve. I purchased a spider gasket and other O rings but have yet to replace. Does this sound like I'm on the right track to fixing the problem?