have u recently greased your front slipyoke? my guess is the excess greas is coming out. happens on mine. check the joint make sure the seals are all good, while youre there look up inside the yoke if you can. maybe take it off to get a better look. there isnt a seal in there, when i do mine i keep pumping grease in untill all the old grease is out. when your slip yoke travels in and out, some of that gears is forced out.