i have a 03 escape. about a year ago i changed the axles in the frontend. recently i have been hearing a poping when i put it into gear,drive or rev. i have checked the axles and there is a little slack, not sure it should be there. every once and a while @ a certain speed there is a quick viberation that stops when i speed up or slow down. we LOVE!!!!! this escape and hope for nothing major. any ideas?