a longitudinally driven slotted transducer has a tubular member with an axial slot extending from one end to the other end . a drive assembly is disposed across the inner wall of the tubular member and supported by journal bearing surfaces extending from opposing sides of the inner wall to locate the drive assembly in a position offset from the longitudinal central axis of the tubular member . the interface between the drive assembly and tubular member comprises a layer of solid lubricant material mounted on the journal bearing type surfaces .