Your supposed to unlock the hub's?
Mine are usually locked as some sort of wheelin is only minutes away. If I know that I will only be driving the streets for a while I might unlock them for fuel economy and it does help drop some of the vib's from the front end.
I never knew that hubs heated up in the locked position. Isn't there more movement in the hub in the free position?
Not wanting to ruffle any feathers, just curious.