Buzzing type sound coming from torque converter or flexplate?

Had this truck for 2 and half years now did so much work to get it up to service and now I got this problem. I've been under the truck before and never heard this. I been chasing a few horrible sounds in the truck one been around since I bought it and when I go 50+ it sounds like a rc car or even a funny sounding supercharger. as soon has you take your foot off its gone and soon as you put your foot on the gas it's back. This happens when cruising at 45-60 then disappears. I never got it fixed because most dealers and shops giving me the cold shoulder or saying nothing wrong. Well now i hear this sound coming from the flexplate/torque converter. I'm not really having any other problems that other then the noise but I think the two noises im hearing are related and now it's just getting worse. I'll post a video of the noise coming from the flexplate/torque converter location i poke a big flathead and pinpointed the sound to this location. You could hear the same sound coming straight threw the screwdriver. I took the inspection plate off but don't see nothing concerning and no play in flexplate. Any ideas of what the sound could be would be very appreciated!!

This is the link to video
https://youtube.com/shorts/LZfiWEkD4Kg?si=DAc7y2PueObck7uB

 

Welcome to the forum. We put together a community thread to help folks just coming around. https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

Inside there, one point of interest:

• Strange rattle noises at back of engine, like marbles rolling around: Several people here and at other forums have found this issue where they describe the sound as loose marbles banging around. Then found their flex plate was cracked in multiple places. Ticking timebomb. Check it out and another one with videos.

Check that out. See what you think. And note there's a black smile-shaped inspection plate with one screw holding it in. You can open that plate and see if the noise gets louder AND use the inspection port to see if your flex plate is potentially cracked.

 

Thanks shifty, the link with the video sounds kinda similar. Mine just might not be as loud as the OP. His flexplate also had very minimal cracks to some others I saw.
Wondering if mine is just loose I took the plate off and couldn't see any damage. The flexplate only rotates when I turned the engine on so I turned it on a few times to get some different views of it but nothing was noticeable.
With now looking back at the old car fax the truck did have a new transmission put in before I owned it so my bet is something came loose. Also i did do a transmission flush in the summer, I did the pouper procedures when flushing so i doubt the fluid is low but imma make sure tomorrow. It goes to the shop this Wednesday hopefully it won't be a arm and a leg with my warranty or say its not a issue or I'll be learning how to put on a new flexplate lol