Toyota Camry 2013: Whine at 2000rpm

I wrote to you last year about a whine in my 2013 Toyota Atara SL that comes in at 1900 to 2000 rpm. You said it could be the gears in the gearbox, which means the car has to be moving, but if you can hear it when you rev the engine in Park. Two dealers I have taken it to don't know what is causing it, one said it could be a characteristic of the car, but that does not solve the problem. It is a good car, but on a long trip it is a pain hearing it all the time. Your help on this would be much appreciated, as it is driving me nuts.