Having manually locked my front hubs (they operate freely) and engaged H4 on my fj40 cruiser there is an intermittent droning from the l/front wheel at approx. 50mph. At low speeds turning a corner L or R forward or back there is an audible noise like one component dragging on another. Can be felt also.this is confined to area of left front wheel only As this does not occur when hubs are unlocked I suspect the hub but not bearings because as stated it is only in 4WD. Am I on the right track?
As per Paulster2's comment, I'd suspect the UJ/CV in the hub - especially if it is worse when turning a corner?
Out of curiosity, what happens if you engage the hub, but leave the gearbox in 2wd (or vice versa), so that the front drivetrain is turning, but not transmitting drive under load?