What was found
AFTER TAKEOFF, CREW NOTICED TRANSMISSION OIL PRESSURE WAS BELOW THE MINIMUM CONTINUOUS LIMIT IAW THE RFM (35 PSI). CREW RETURNED TO BASE AND SHUTDOWN. MAINTENANCE REMOVED, DISSASSEMBLED, CLEANED AND REINSTALLED SNUBBER. ALSO, R & R THERMOSTAT. PERFORMED GROUND RUNS, LEAK AND OPS CHECKED GOOD. FUNCTIONAL CHECK FLIGHT COMPLIED WITH, NO DEFECTS NOTED.