Here's the info I got from a MORryde Rep:
Oil Bath bearing are great to Over the Road Trucks, because they're always moving.
With an RV it sometimes sits for months without moving, thus the oil would drain off the upper section of the bearings not in the oil, so when you started moving part of the bearings would be dry and also possibly have some rust.
So he recommended staying with tried and true Grease for RV use.
2018 Silverado 3500HD High Country Dually 4x4 Duramax/Allison, 2016 Redwood 39MB, Disc Brakes, Mor/ryde IS, Sailun 17.5" H tires, 5.5K Onan, Dual ACs, auto level, auto sat dish, stacked washer/dryer, residential fridge, King sleep number. Michelle & Ann