I have a m50D trans in my truck and i noticed a leak at the fill bolt when i first put it in so i went to the local parts store for the little metal washer gasket deal and all they had is a universal ones i swapped both the fill and drain plugs and now they both leak. It is torqued to haynes manual spec but now they both leak so I'm thinking its the wrong washer any ideas where to get a new factory one? Ford doesn't have it listed in the catalogue and someone suggested thread tape a while back but that didn't last long can i just run a thin bead of rtv under the head of the bolt?