A variable geometry turbine turbocharger (1) includes a gear driven adjustment ring actuator mechanism (300) supported within a housing (16) via a resilient mount (70) disposed between the mechanism (300) and housing (16). The gear driven adjustment ring actuator mechanism (300) rotates an adjustment ring (350), which in turn adjusts the position of the vanes (30) of the variable geometry turbine (2). The resilient mount (70) accommodates the heat-related expansion and contraction of the gear driven adjustment ring actuator mechanism (300).