Poshaman

Don't you just hate it when that happens?

USMC_DS1

Perhaps one of your pulleys or the WP is the cause. If you remove the s-belt you'll be able to check for rough play(worn/broken) bearings in those pulleys and/or WP. Just turn the pulleys by hand once you have the s-belt off. They should have zero noticeable play in the xyz axis... only free play should be in the rotational direction. Also look for fraying on the edge of the s-belt as well... another indicator. If you haven't replaced the s-belt yet... this would be a great time for some preventive maintenance while you have it out.