I HAVE AN F4i AND I HAVE A SLOW OIL LEAK FORM BEHIND THE MAIN SPROCKET... DOES ANY ONE KNOW IF THERE IS SOME KINDA SEAL THAT I NEED TO REPLACE OR WHAT IT IS? I HAVE CLEANED IT AND INSPECTED THE AREA AND THERE IS NO SIGNS OF A CRACK OR ANYTHING SO IF YOU CAN LET ME KNOW WHAT I NEED TO DO IN ORDER TO GET IT STOPPED I WOULD GREATLY APPRECIATE THE HELP......THANKS