Squeaking like a slipping belt but not

2015 Tundra 5.7 CrewMax is squeaking. Doesn’t sound like the belt though. I tried to upload a video of it squeaking but the site won’t allow it. I turned the flywheel but it was smooth and didn’t make any noise nor was it loose.

 

While its squeaking, take some water and pour it on the belt. If the squeak goes away, its the belt, if not it's probably a pulley.

 

Yep, probably the idler pulley. my 2016 chirped, then chirped more often. pulled the idler pulley off and it felt nice, spun nice, no noise, so I replace the tensioner pulley since it was cheaper. Next morning chirp chirp chirp again.
This time replace the idler pulley and it was quiet again.

 

https://www.tundras.com/threads/can-anyone-identify-this.152368/

Does it sound like this?

 

The kit with an idler, tensioner, and belt is cheap insurance. The only thing on my truck to ever leave me stranded was a belt break caused by a bad tensioner.

 

I had a similar issue. Did the water spray test. Water worked. Swapped the belt. Squeak came back after a few months. I think the tensioner can still be the issue even if the water trick works because the squeak can be due to lower tension on the belt. In my case a replacement tensioner fixed it (along with new belt). It's pretty easy to do the tensioner. My tip is to remove the fan bell bolts (not the water pump) and you can access everything you need to do the job from the top without having to remove the skid plate or work from the bottom. No need to actually pull the fan out of the shroud or remove the shroud. Just get the fan loose off of the water pump and it'll move around enough to swap the tensioner.

Good luck.