I am getting ready to reconnect my lower to upper unit of my 1988 5.0L outdrive and then both back to the transom mount. I have heard that you should apply several coats of sealant or gasket maker in addition to the actual gaskets. Is there any truth to this? there was some residue on these surfaces before but I thought that it might be from someone trying to use old gaskets and everything that I am using is new.