I'm trying to put a new rear main engine seal on a 3FE from a 92' 80 series, but having some difficulty. Is the a special tool or technique for getting this sucker on - fit is extremely tight and it seems it would need to be stretched out a bit to fit on. Also, the old seal pretty much disintegrated when I took it off. How squeaky clean does the surface have to be for a new seal to be applied? If there is a little residue from the old seal is that OK? TIA.