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
A simple guide to adjusting a Shimano Nexus hub gear | As Easy As Riding A Bike
SHIMANO NEXUS SL-C3000-7 REVOSHIFT, 7v - Emilia Sport