Clicking/hissing noise?

[jprice1707]

I've been following this forum for a while now, getting tips and information on my 16 Silverado. Now, I'm finally needing some help. It's a '16 Silverado 1500 z71 5.3 engine. The transmission went out of it last month and I had it rebuilt. After I got it back i noticed there was a loud hissing/clicking sound coming from the front. I figured it was the transmission since it never did that before the rebuild. Crawled under the truck to locate the sound. Turns out it isn't coming from the transmission. It's coming from front/side of the engine. The belt doesn't look damaged, the pulleys don't look bad. (From my eyes, but I'm no mechanic) then i thought maybe a lifter tick? It only does it during cold starts. Then after a few minutes it quiets down but it's still there. And you can hear it over the aftermarket exhaust. And when you give it gas, it sounds to me like a weedeater. It's hard to explain but i can get a video of that if needed. I was also thinking maybe exhaust leak? Idk

No engine light.
Hooked up a scanner from advanced auto and no codes.

My buddy hooked up a tuner a few months ago to delete dod/afm and said on his laptop there was a lean on bank 1 & 2. I checked for leaks by spraying around the hoses and didn't see anything. Does have a Rough Country cai that i installed a few years ago.

First video is cold start. 2nd video is after it warms up.
I'm hoping it's something stupid and easy but wanted to get others opinions before it gets worse and I'm dishing out a bunch of money.

Thanks in advance
 

 

 

[jprice1707]

Wouldn't let me post 2 videos in the same post, but this is after it warms up after a few minutes