The Vault system works on a tapered shaft axle. UFP is the Mfg. I'm getting ready to replace the bearings and refill the system after 7 years. Pretty easy to do.

My dad has oil bath on his 7k dexters. Id like to change over. Oil is superior IF you can keep it clean and dry.

Grease runs way cooler than any oil.

Grease if your dunking it a lot. its hard to find a water tight seal for the oil bath.

Air tight seals

Just my experience. I went coast to coast five years in a row. 31k miles on oil bath hubs over 6 years. Never a problem. I changed the oil often. Your experience may very.

I found out my axles are AL-KO Axis and 7,000lbs 6-lug. So I'm guessing the Vault system may not work, if that's the case I am not buying new axles.

The worst case scenario is the reason to stay away from the oil baths. I think they work great when they are sealed, but you find out when you have a seal leak when your wheel and hub come off the axle and it is trashed. This will not happen to all, but I have enough things to worry about and maintain. With grease and a leaking seal, you have lots of warning. In my world, I have enough friends who have experienced this to stay away from the oil baths.

Kept the same setup, the Vault system wouldn't work and I decided not to go with Buddy Bearings.

The axle that had the inner seal problems also had a damaged bearing, it looked like it was dropped before installation. This is not on Manning since they get their axles assembled and ready for installation. But I tell ya, never expected all these problems from a brand new trailer that's not even a year old yet. Fingers crossed this is it... nothing but smooth pulling from now on.