Abstract: A spacer is used to set the running clearance between parts in a power transmitting device. The power transmitting device contains a housing, a shaft rotatably mounted in the housing and a ring gear mounted on the shaft for rotation therewith. The ring gear is capable of deflecting in an axial direction under load. A stop member, fixed to the housing, is positioned to have one end adjacent one side of the ring gear. The stop member is installed to be in abutting contact with the ring gear. The spacer is formed of a material capable of wearing away when contacted by the rotating ring gear to produce a gap of a predetermined thickness between one end of the stop member and the ring gear. The one end of the stop member will prevent the ring gear from deflecting axially under load a distance greater than the predetermined distance.