I have a 2006 F150 XLT with the 5.4 Triton V8 in it. The truck has 109,000 miles on it and it whines. I am assuming it's either the alternator or power steering pump, but I've noticed three things that steer it away from being the PS pump. 1) The whine doesn't get louder when I turn, 2) I've heard my PS Pump whine in the morning when it's very cold and that whine is a lot louder than my present whine, and 3) I can hear a faint almost chirping-like sound when I give it more than half throttle along with the whine. For comparison, the whine sounds almost like a supercharger, but not as loud nor direct.