What is this noise from left side of engine bay? Timing chain tensioner or belt tensioner pulley?

I have noticed when I hit the brakes to slow down, the squeal goes away completely until I hit the gas pedal again. I was thinking the belt for sure and was curious if it could be one of the pulleys. How long do pulleys and/or the belts usually last before needing to be swapped?

Sorry, I know this is a 3rd gen forum and mine is a 2nd gen but it's the same 5.7L engine I believe.

 

I would say 60k without squealing isn’t too much to ask.

 

Get a mechanics stethoscope. I thought my tensioners were going bad. Also thought my power steering pump was making that noise. Nope, crawled under there and listened to each pulley/device, when I got to the alternator it was like someone jackhammering inside my ears. Insanely loud horrible metallic noise that I couldn't pinpoint without the stethoscope.