What is this squeal? I'm stumped.

Had my front brakes done before a 1400 mile trip in October. Had no issues. When I returned, I washed my very dirty truck including the engine bay. Drove home and heard a faint squeal. Couldn't pin point where it was coming from.

The sound has become a little more pronounced. It is not constant and seems to begin around 15mph. The squeal/whine changes pitch according to speed. For instance, if I am going 45 and take my foot off of the accelerator, the squeal will change in pitch until I come to a stop. The truck drives without issue beyond this sound.

I am not a mechanic, but I am stumped.

Things that I have done to the truck over the last month:
Lubed u joints
New lower control arms and ball joints
New CV axles
New hubs, seals, and bearings
Replaced uniballs on Camburg upper control arms

Any ideas? Thanks in advance. Terrible video shot by my wife to exhibit the sound:

https://www.youtube.com/shorts/IC7yBF85NtE

 

Sounds like a firetruck....3 blocks away..can you tell if its coming from front or underneath?

 

Yeah, that's bad.

It's something rotational for sure and appears to be speed dependent. You can make sure by rolling at a constant speed and then manually shifting the gear to see if the pitch of the sound changes. If it does, it's likely engine related (although I'm certain you'll find it's not).

If I had to guess, this is hub related or something like a brake pad dragging. Can you tell if it's front or rear?

 

Last time I heard that sound it was the ring & pinion. Drain the diff and look at the oil for metallic particles.

 

Does the sound change pitch or go away if you ziz zag down the road?

 

That's kinda my thought. Easy way to check is to see if there is a visible pinstripe on the back of the rotor.

Hope it's that because you just bend back the shield and job done.

 

Ended up being a bent heat shield rubbing on the drive line.

Thank you all for your input!

 

Glad it was something easy to fix!