The lube gains heat from contact with gears and bearings, gets flung to the sidewall of the gearcase and transfers ... head gearcases now use 80w-90 gear oil instead of corn head grease.

Symptom: A main gearcase on a combine, forage harvester or other machine is covered with oil that’s dripping on the ground. Panic diagnosis: Leaky shaft seals, blown gasket or cracked gearcase ...