My Toro 22" self propel started making a grinding noise today. After seeing a youtube video, I looked at the self propel cable, and it had a lot of slack at the top. So, I loosened the bolt holding the self propel cable. The video said to tighten up the slack, but when I did this, the grinding GOT WORSE. However, when I LOOSENED the slack even more, the grinding stopped....but so did the self-propel function. I cannot find a happy medium in the cable. Tight cable means self propelling, but the grinding is loud. Loose cable means self propel stops working, but the grinding stops. Any advice?