Following a series of failures of the lubricated couplings of the Reactor Feedpumps at the Peach Bottom Units 2 and 3, thermographic monitoring of these couplings was initiated. Baseline data was collected for all six feedpumps and a monitoring frequency was established. Data was collected over a three month period, and a trend-to-failure was developed both qualitatively and quantitatively. The motion of the coupling was effectively strobed by the infrared camera to allow the interpretation of heat patterns on the coupling surface. By keeping stored infrared images and comparing them to the as-found condition during coupling inspections, it became possible to identify heat patterns that were characteristic of lubricant degradation of coupling tooth breakage situations. In addition, data was compared to certain operating parameters to help determine root cause for the failures. To accomplish this, real time temperature data was obtained for selected points on the coupling profile during certain transients which presented a comparison to changing parameters. In this way, certain design criteria were more thoroughly analyzed for their applicability to the currently experienced loading of the couplings.