Sealed bearings
Not really. A sealed bearing is what you would have on the front hubs of your ram truck. Sealed bearings do not require lubrication, they tend to be more closed off, offering no route for contaminants to enter
The “sealed bearings” on your RAM that you speak of are known as unit bearings and you should be thankful that they don’t use them on the trailer axles because they are not serviceable and they eventually self destruct without much warning.
RAM uses the unit bearing assembly because they are cheaper to build. The OEM front axles on a 4x4 RAM are made by American Axle Manufacturing or AAM. They use the same axle on the 2500 and 3500 SRW and DRW.
The unit bearings are a cheap throw away substitute for “real bearings” and hubs. They save money on the OEM assembly because they are a pre assembled “unit bearing” that are a bolt in and go bearing that doesn’t require the set up time that regular hub bearings take. Unit bearings also allow them to use smaller stub axles, smaller spindles, no locking hubs and overall less metal in the hub assembly.
The problem with unit bearings is that there is no maintenance, repacking or disassembly for inspection. The two bearings are mounted closer together than a regular hub set up and can’t handle the side load that a regular hub can with the bearings spread farther apart. It’s even worse side load if you have a dually with the spacer they bolt on for the offset wheels. Think of how you use a cheater bar to get more leverage on a tight bolt.
They save money by use a sliding collar on the passenger side to “unlock” the axle to prevent binding when in 2wd mode instead of locking hubs at both front wheels. Without locking hubs the front axle is constantly spinning as it is pushed down the road putting miles on the u-joints, bearings, gears etc.
One of the first upgrades I made on my 3500 DRW was to get rid of the unit bearings and convert the axle to a DANA 60 style with manual locking hubs by installing the YUKON free spin conversion. Now I have serviceable Timken bearings, heavy duty spindles and stubs that won’t leave me stranded on the road like an exploded unit bearing. I eliminated all of the parasitic drag by not spinning the front axle assembly as I’m driving down the road anymore by having the locking hubs. If I need 4x4, I can lock the hubs and the axle is right back to a shift on the fly, same as the OEM.
Overall unit bearings on a trailer or any vehicle is a bad idea. FWIW