A transport system for delivery or retrieval of a biostimulator, such as a leadless cardiac pacemaker, is described. The biostimulator transport system includes a docking cap supported by a bearing within a bearing housing. The bearing allows relative rotation between a torque shaft connected to the docking cap and an outer catheter connected to the bearing housing. The bearing housing and the docking cap include respective bearing retainers that constrain the bearing within the bearing housing without a weld attachment. The weldless retainers of the biostimulator transport system provide a robust mechanical securement of the bearing that is not vulnerable to corrosion. Other embodiments are also described and claimed.