have an oil leak I'm my 86 m1008 that I cannot for the life of me find. the bell housing is soaked its not rolling back down the valley. its not the vacuum pump. its not the valve cover gasket. best I can tell there is a small clean spot on the back top of the passenger head just behind the intake manifold. looks like there is a plate there with a bolt and and a stud? any know what that is? and if it is a point where oil could leak?