I am working on a Scag 61 in deck with a 27 HP Kohler engine. When I engauge the baldes the Drive Shaft makes a loud noies. With the Deck up it is normal. This is the U joints bad in the Drive Shaft. I checked with Scag and they only sell the complete assembly. I just need the U Joints! Has anyone ever replaced these U joints. If so what is the part number?