Not sure if this is going to help, but just something to consider. Not on my 4Runner, but on my FJ I had an ARB rack and returned it for the Baja Utility rack, which I REALLY liked. Back to the ARB, are you hearing a humming or airplane like noise when driving? My ARB, at certain speeds, vibrated the crossbars like guitar cords. It stumped me until I reached out my window and had my hand on the crossbars and felt them vibrating massively at certain speeds. It was strange and ARB didn't believe me until I had someone at the dealer confirm. Then they took it back shipping an all. Anyway, not sure if your situation is the same, but it sounds somewhat similar. Hope that helps!