Grinding/Screeching noise when shifting into 3rd Gear (I'm assuming). What's the Diagnosis?

[Biggie]

https://imgur.com/a/cZhTgr7

As the video shows, when I accelerate fast and hit 3rd gear, there is a high-pitched grinding, before the noise stops after a few seconds. I've never worked with transmissions much, especially automatics, so any help would be much appreciated.

 

[pjtoledo]

over the internet that sounds like a belt slipping

 

[Biggie]

over the internet that sounds like a belt slipping

It's always at a specific RPM and only for a few seconds, but if that were true it could save me a few thousand dollars. I guess I could try revving it up to that level tomorrow and get back to you.

 

[alwaysFlOoReD]

Can you get that squeal while in park? If so, take off the serpentine belt and see if the noise disappears. The noise disappearing means a pulley bearing.

 

[BuckHunter]

Sounds like a belt to me also. My 79 f150 does the same thing.

 

[Shran]

Yeah, belts for sure!

Check all the alternator/PS pump/AC brackets and mounting bolts as well, had two break off on my F150 and it would squeal like crazy. Belt appeared to be tight but it would loosen up under a load and the alternator bracket would move.