Bad fan or something else?

Hi everyone. Today this sound started when I headed out for a second drive today. It looks like the sound won’t start unless the truck has been driven around the block for a bit and it will completely fade out as soon as I park it. I’m not sure what the sound might be but it sounds like is coming somewhere near the center towards the engine area. I checked the fan seems stiff enough no noises when it’s off and forced to move. Any tips? Thanks in advance.



https://youtube.com/shorts/68_KZpAHt8k?feature=share

I am unable to upload the video this is the only way I could think of doing it

 

I’ve been researching for the last couple of days trying to find some information but I’m getting many different topics. Today I tried the reverse/drive/drive/reverse and I’m getting a clunk big enough to shake the truck. All symptoms are pointing to a bad u joint just not entirely sure which one.

Here is the video for reference


https://youtu.be/HBpktAjovj4