Dually Wheel Problem?

[Baldicon]

I have a 2017 Ford F350 diesel dully long bed super cab with a little less than 20k miles. I was experiencing a loud squeaking sound, and found that it was coming from the overload springs rubbing against the rubber stops. After cleaning with WD-40, I sprayed a coat of dry lube on both the springs and rubber stops and the squeaking noise was eliminated. But while confirming that the squeaking noise was gone by rocking the truck from side-to-side, I noticed a popping sound coming from the wheel hubs (both sides). I could place my hand on the wheel hub cover and feel the popping. At that time, I had a travel trailer connected (1000 pounds tongue weight) and probably around 400-500 pounds of stuff in the bed. With this load, only the rear of the overload springs was engaged. I could not replicate the popping sound with the truck unloaded or with the 5th wheel connected. Although with the 5th wheel connected, I could hear a faint squeaking sound not coming from the overload springs. This is the first dually I have owned so not sure if this is normal. Is there some play built into dually wheels for load distribution, or other reasons? Again, both sides made the same noise maybe. Would like to get some feedback before I take it in to local dealer. After the response I got from them when I called about the loud squeaking noise, I don’t have a lot of confidence in their service department.

Hope I made sense with my description. Any feedback will be greatly appreciated.