I'm going to oil bathe this shimano nexus 7.. the proffesional bike repair person I asked to do this for me sprayed wd40 in it, €80 later I decided to just buy
Shimano Nexus/Alfine 3, 4-, 7-, 8-, and 11-Speed Technical Information
Shimano Internal Gear Hub Service
Shimano Internal Gear Hub Service
Alfine 8 speed hub service
Shimano Nexus 8 Speed Hub Reassembly - Putting It Back Together... - YouTube
SERVICE MANUAL SHIMANO NEXUS 7-SPEED HUB - Avantum