What was found
(CAN) ON LANDING AN ABNORMAL NOISE WAS HEARD FROM ENGINE COMPARTMENT. ENGINE WAS SHUT DOWN AND IT WAS DISCOVER THAT THE FORWARD COUPLER OF THE ENGINE -TRANSMISSION X HAD HEATED UP. THE SEAL HAD RUPTURED ALLOWING THE GREASE TO EXIT HEAT UP THE COUPLER AND FURTHER MELT THE SEAL. ALL 4 TEMPLATES ON THE COUPLER HAD TURNED BLACK INDICATING AN OVERTEMP CONDITION. AT THE DAILY INSPECTION/PREFLIGHT THERE WERE NO SIGNS OF GREASE LACKING FROM THE COUPLER AND ALL 4 TEMPLATES WERE NORMAL. THIS VISUAL INSPECTION WAS CARRIED OUT BY THE PILOT 1.6FLT LVS PRIOR TO DISCOVERY OF THE FAULT.