This paper presents a novel spline couplings test rig. Its peculiarity is to allow angular misalignments between hub and shaft in order to investigate the behavior of spline couplings in real working conditions, in particular, to investigate fretting wear phenomena. A preliminary experimental activity has been carried out showing a correct behavior of the test rig from all points of view. A preliminary approximated estimation of the test articles fretting wear has been obtained by means of two experimental parameters: Ra roughness and the amount of angular rotation clearance. An estimation of the Ruiz parameter has also been obtained.