The Lockwood instruction book says to use LOCKWOOD Gear Tooth Paste. "In the model T motors, remove the grease plug (‘G’ in Fig 7) and insert the grease. Do not FORCE the grease under pressure as it may clog the pump." "Two or three times a season it is well to take off the propeller and gear housing head and examine the gear case to make sure there is enough grease."
The grease plug ‘G’ is just below the anticavitation plate, towards the front, on the starboard side.