What was found
(CAN) WHEN HYDRAULIC PUMP AND TACHOMETER GENERATOR WERE REMOVED TO REPLACE TRANSMISSION OIL PUMP SEAL, THE TACH GENERATOR HAD TO BE PRIED OFF. THE DRIVE SPLINES ON THE TACH WERE WORN RAZOR SHARP, FURTHER WEAR WOULD HAVE RESULTED IN TACH GENERATOR PROBLEM. INVESTIGATION FOUND THE WRONG LUBRICANT WAS USED TO LUBRICATE THE SPLINES. BELL 204-040-755-005 WAS USED INSTEAD OF ANTI-CORROSION COMPOUND MIL-A-907.