I recently just started hearing this whine and I managed to record it when it was really bad one day. It's not normally this loud, but it is there and I can hear it when I'm idling or driving slowly. I have already had the alternator checked and serpentine belt + tensioner pulley replaced. Timing belt and water pump were replaced at 120K and it currently has ~195K miles on it so I think those should be good to go. I change oil every 5K with 5W-30 synthetic. Transmission fluid was changed at 130K as well. I did recently replace power steering fluid but the whine was there before and it doesn't change tune if I'm turning the wheel or not. It seems to be engine rpm dependent. Any help in diagnosing this problem would be greatly appreciated as I really want to keep this truck going for a lot longer. Thanks for taking the time to read through my post and have a great day.