Today I heard a grinding noise in the front end of my maverick. It sounds like it is coming from the from drivers side cv shaft. The shaft seems to be tight and my front diff is full of oil. It only does it at slow speeds and it grinds and stops and grinds and stops in a constant rythem. It doesn't do it all the time just here and there and once you start going faster it stops. It sounds to me like gear grinding but I can't find anything wrong. Any ideas or anyone with the same problem?