A bit of guessing
There are Never-Lube, EZ-Lube, and traditional lube bearing, hub and spindle assemblies.
On the greasable bearing setup, after you remove the wheel and the large aluminum center cap within the wheel, there is a LARGE clear or sometimes red plastic cap with a rubber plug in the middle about 1 inch in diameter. This indicates you have greasable bearings inside. There is an O-ring inside that plastic cap that is usually good for reversal repacking. If under this cap is a cottrrpin, retainer ring, and nut about 1.5 inches in diameter.
these plastic screw on caps hubs and bearing sets can be greased or oiled. Oiled solution is called Kodiak XL pro lube:
https://www.google.com/search?q=kodiak%20xl%20prolube%20kit&ie=utf-8&oe=utf-8&client=firefox-b-1-m
Better than grease in constant commercial use. In the past not generally recommended for units that sit for a long time without some wheel movement due to oil leaking past a dry seal. There frequently have a more expensive felt oil seal versus the rubber seal for greasable solutions found on the same bearing set and hub. You can clean out old grease and use the oil bath or vice versa. If oil now, just keep the oil at bottom of rubber cap and drive for 100,000 miles.
The EZ-Lube is like the above but has a grease zero and a hollow spindle that allows you to remove that 1-inch rubber plug and grease the assembly without removal, cleaning and repacking bearings. But not too much new grease at a time.
I have never seen a Never-Lube (NevRLube) hub, but it is a complete non-serviceable assembly, with a traditional metal cap on the hub.
https://www.etrailer.com/Trailer-Hubs-and-Drums/Dexter/8-388-80UC3.html
these assemblies generally need to be pressed in and out of the hub. If no excessive play or grinding noise when spinning freely, it is fine.
JohnD222
Based in Florida except summer
2013 36FWS Lifestyle (our great 2010 Cameo 36FWS has happy owners)