Mark, I bought the F18D about 4 years with a homebuilt FEL on it, from a privite indivdual , it was plumbed this way when I got it. There 2 hydraulic lines that come out of the right side of the tranmission about 4inchs above where the gear/range selector goes into transmission. I have the plugs that came out, they are 27mm(1 1/16) hex heads. Its very tight in there, I will have to remove some sheet metal to get some pictures. The hoses then quick connect to a Prince 2 spool loader valve. When loader is on the tractor the valve under the set is open, when loader is removed (prince valve stays with loader) the valve under the set must be closed. I will post some pics of the setup when I get them. Hope this helps
Dave