This is on a 2008 Navigator EL.... happens on all gears and the noise follows the rpms and is present even at idle, turning, etc etc. Best way to describe the sounds is a whine sound like I have a roots blower underhood. Does this jive with the power steering pump going out? Is it beyond recovery? Will a flush and fill bring it back to life? I'll see about getting a video up and going tonight but curious of what some of the possible culprits could be.
Hnmm, could be the power steering but that is more of a whine and gets louder when turning. Turn the truck on, pop the hood, turn the wheel while another listens. If turning the wheel doesn't change the pitch/level it could be the fan clutch not dis-engaging. Post a video if you can.
Can't get the audio to play, but here's something to check. It's very common:
Check the idlers on the serpentine belt. They should turn very smooth/quiet but they usually start to get rough/noisy sometime after 50k miles. There are 3. One is the spring-loaded tensioner for the belt, the other 2 are stationary (just an idler pulley with a bolt through it into the block). They each contain a #6203 bearing ($1.50 each) and they can be pressed out/in with a couple of different sized sockets in a vise. Don't hammer them or you'll risk damaging the pulleys. Getting the belt off/on takes a bit of patience but other than that it's a very simple job. Don't let the parts guy sell you the complete idlers. All you need are the 6203 bearings, available at any local parts place.
I should be more clear. I believe it's the fan not disengaging. I had this problem with mine. Sounds like engine is straining and a weed blower is constantly roaring. I finally convinced the dealer to check it with their laptop-it said fan-0ff but it was clearly engaged full time. Swapped out the fan and it problem solved.
Fan Clutch....hmmm I'll check it out. The engine isn't straining at all though and it doesn't have that jet engine is going to suck everything in front of it sound to it at any point in time. Just that annoying constant whine like a roots type blower. I know lots of peeps that pay good money for that kind of noise.... but would prefer the power that comes with it .......
So replaced the tensioner assembly, upper right smooth idler, ribbed idler, and belt......and all is quiet now. After spinning the bearings when they were off it would appear the ribbed pulley was the culprit as an FYI for anyone else who has this issue.