the TRD and the Cusco diffs for the starlet are exactly the same, they are both made by KAAZ. check your chassis plate for the type of gearbox you have, because you may have the optional box with the slip dif inside. in which case youll have to get the oil from toyota, as its a viscous diff. if you have a c56 gearbox, then just get some good synthetic 75w90 oil for it.