i bought and replaced my front hub assemblies about a year ago due to a loud highway hum. the ones i bought look as if they could be greasable there is a hole in it that is covered by a plastic plug with a rubber o-ring at the tip, and it has a screw holding it in place. is this possible that it colud be greasable? there is no grease fitting., but i have the loud hum once again!!!

 

I have never seen one that was greaseable but on a trailer. What the hell, check it out but be carefull and make sure you use wheel bearing grease for a higher heat range and not a Lithium.