The wheel seal is supposed to fit very tight in the wheel assembly and protects the wheel bearings from dirt water and other debris that can cause damage.
Wheel bearing grease leak.
So always pick a wheel bearing grease that is designed for the temperatures of your application to avoid grease leaking out of the bearings.
Just a quick video on what i do to maintain and keep grease in the bearings on a trailer.
But in addition to the primary tapered roller bearing in the hub there is also a needle bearing that supports the axle shaft on front driven wheels in the f 250 and several other f series trucks.
Your wheel bearings were probably originally lubed with a lithium 12 complex grease a perfectly good grease for wheel bearing use even on a boat trailer if it s maintained.
Grease is leaking from the bearings.
Inside the wheel bearing is a tremendous amount of grease that keeps the bearings running smooth cool and free.
Be sure to follow the manufacturers directions for properly filling your hubs with the bearing protectors.
The bearings that support the wheel ends are heavy duty and able to handle most any load you can put in or tow with your ford super duty.