Marine Trailer Wheel Bearing Grease from our boat prop/trailer bearings. They use the same type of tapered roller bearing and it's great at keeping out water, salt air and corrosion.
Green Grease, waterproof for trailer bearings, kind of just what I had so that is what I have been using. I give the fitting a little shot with every oil change.
I used to use Kendall Super Blu (blue grease), but I nobody crries it locally anymore, so now I use the red grease from tractor supply. It appears to be the same stuff as Lucas "red and tacky", and might be made by them for all I know.