I just bought a 2002 terramite T5C and want to change hyd oil.  How do you drain the tank? In the owners manual they talk about a sump that needs cleaned where is it?  The oil they say to use in API SFCD 15W40  is this regular car oil? The only thing I have seen so far is SGCD rating and when I looked on the API web site it said that the SFCD was not used anymore.  Any thoughts would be welcomed.    big dan