Mercury Mariner 30/40 4-Stroke Outboard Service Manual 1998, Page 458Get this manual
BIGFOOT GEAR HOUSING
12Install thrust bearingCoat thrust bearing with Super Duty Gear Lubricant
Super Duty Gear Lubricant (92-850737 1)
Thrust Bearing
13Apply Super Duty Gear Lubricant to bearing surface of reverse gear and install reverse gear