Weird Grinding Noise

2012 Tundra 5.7 When I start my truck cold(sometimes hot) I get this intermittent grinding/rattle/creaking noise for like 1-2secs then it goes away. I'll also get the same noise on very light acceleration usually on first and second gear and/or slow speed corners, but not all the time and seems to not happen as frequently the hotter/longer I drive it. Can't for the life of me tell where it is coming from. I thought it might be something like a fan blade hitting the shroud or a heat shield rattle because the noise can happen on start up(not always though) were the truck is not in gear and not moving. I'm leaning towards the transmission. I bought the truck used and have put on about 30,000 miles and bought with 45,000miles on it. I'm going to drain/fill the trans fluid hoping its an oil thing. Oh, I don't notice any slip in the trans or anything abnormal other than I think its slightly slow to up shift under light acceleration.

Here's a video of already in first gear and a very slow acceration. You can see after about 20-30ft the noise stops.
https://youtube.com/shorts/p8OGycDgM_0?feature=share

Any thoughts on where the grinding might be coming from? My brother said, "is that your abs malfunctioning?" I don't think so as I think I would get a idiot light or something.

 

Check heat shield that’s under the driver side seat.(under the truck) to see if it’s loose. I get almost a similar noise on acceleration because my heat shield is loose. I also got a grinding noise like that on braking real hard going down an off ramp. Found out my driver side brake caliber was ceased. So the abs system wasn’t functioning properly even though it tried to work. But you’re having the noise on acceleration so it may be the heat shield or something else rubbing. Good luck. This is a tricky one

 

I did just replace both front brake calipers recently. Though since it never seems to make the noise associated with braking I'm kind of leaning away from that, but who knows, maybe I messed something up. The only two things I've down to the truck since purchase other than oil changes is replace a bad speed sensor on the trans and front caliper and pads/rotors all around.

 

Just listened to your video again. The bash plate that covers the oil filter might have a loose bolt from changing oil. It would make that noise on acceleration.

 

Don’t rule out one of your cats gone bad and broke up inside! Ask me how I know…