As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CRUISE FLIGHT 1500' MSL MAIN TRANSMISSION OIL PRESSURE STARTED FLUCTUATING BETWEEN 1.1 & 2.8, MOMENTS LATER PRESSURE DROPPED TO ZERO, TRANSMISSION TEMPERATURE REMAINED NORMAL. ALL ENGINE INDICATIONS REMAINED NORMAL. MADE LANDING IN FIELD 6.5 NM SOUTHWEST OF KSKF