I am changing the oil in the gearbox for my 66 BJ8 for the first time. When I removed the drain plug from the overdrive I pulled the strainer off the plug to clean it as suggested. When I removed the strainer I found 3 gaskets underneath. Does anyone have any idea if these 3 gaskets should be there? When I look in the manual it makes no reference to them. It does mention a spring washer and a regular washer that connects to the bolt for the strainer. The plug does not have the bolt connected to it. One of my manuals makes reference to a 2nd type of plug.