Hello, I'm new to the forum. I've mostly been a spectator until now.
I have recently bought a 08 f150 5.4. It needs a little love, but one thing that has me scratching my head is a high pitched gargly whine is heard when accelerating at any speed.
I've recorded a video for reference. I think it may be alternator whine. But I'm not exactly a seasoned mechanic. Any help would beuch appreciated. Thank you.

 

My guess would be power steering pump or alternator. My alternator is original but have read here that most alternators don't make it past 150-200K. If you're sitting still and turn the wheels do you hear the noise? If you can safely do so a long screwdriver or something similar could be placed on the alternator and held to your ear to pin point the location. I've done that before on other projects.

 

Yeah, if the noise doesn't change when you turn the wheel to full lock, it's likely your idler pulleys, those tiny bearings when worn out sound exactly like that, It's also a good idea to change the tensioner while your in there.

 

This^^^ It's a common problem and a relatively cheap and easy fix

 

I had a pretty similar noise when driving, I dropped the transmission pan and did a filter and fluid change and that got rid of the noise. Do you get the noise when in park and revving the engine? If so, I would definitely suspect the pulley bearings and/or tensioner though. Both fixes are pretty easy and cheap to do.