Question: On corn heads that have row unit gearcases lubricated with corn head grease, do you really have to fill them by laboriously pumping grease into the zerk on the bottom of the gearcase until grease reaches the bottom of the check plug hole at the top of the gearcase? Or is it OK to pull out the check plug on the top of the gearcase and pump grease in from the top?
Answer: It’s better to fill from the bottom. Corn head gearcases are oddly shaped units. If grease is pumped in from the top, air might be trapped in some of those nooks and crannies, causing the gearcase to appear full even though it’s not.
Pumping grease from the zerk on the bottom forces grease up through passages and channels designed to drain toward the sump, reducing the chance of air pockets. If you choose to fill from the top, reinstall the check plug and run the corn head to warm the grease, then recheck to make sure the grease level is still at recommended level.
