Remove the 8 bolts (6 on mid wheels) and the cover to drain the oil.  A funnel can be made with thin sheet metal.  Use a new gasket and fill with synthetic 50W transmission oil.  The reaction arm bearing oil should be changed (also synthetic 50W) every time the engine oil is changed.  The local service manager says oil samples from reaction arm bearings often show high particle count so he does not recommend taking samples.