These are two pictures of a bathroom under sink drain with the trap and all other hardware removed. I am replacing the drain and trap with new pvc stuff. I run into an obstacle with the existing old drain where it goes into the wall piping. It looks like there is some threaded adapter in the pipe, but the the chrome drain pipe is in there good. Attempted to loosen actual 45 degree drain pipe or threaded nipple below it, but no room to get a big enough pipe wrench in there to do so. Any suggestions? Heat? Any special gizmo? Penetrating oil? What would a Pro do? Thanx!