As 94 Harley said, Ive replaced the front eccentric bearings on a couple of machines, they make a clicking noise but Ive never seen them slip unless you have teeth missing on a sprocket.

 

not to get off your subject... but i was out plowing and while pushing snow.. i noticed it felt like it was slipping.. it seemed just like when the belt would get wet when out mudding... do you guys think it might be time for a new belt..? or to clean up the inside of the pvt? or both\

merry christmas