Strange noise

So there's been a strange noise going on in my '04 4.7 l tundra for a while. At first I thought it was wheel bearings but we checked those by manually turning the rear wheels and there's nothing there, and besides that the sound is intermittent. It almost sounds like a grinding or sheet metal flopping around. I can really only hear it from inside the cab with the windows rolled up I've tried rolling the windows down and listening but nothing The tire noise on the road is too loud. I've taken the carrier bearing off the drive shaft and spun it around by hand while still attached to the drive shaft with the drive shaft kind of just hanging there, and everything seems fine in the carrier bearing no resistance no strange noise spins freely. The other day I lifted up the back end using a jack and I started the truck and went back there under the truck while it was in drive and idling and the tires were spinning. I could kind of hear the noise but I couldn't really pinpoint it and it's intermittent so I had to sit there for a while and listen to it come and go. I didn't have somebody to help me by giving it some throttle so I could listen to it while it spins faster to see if it got louder. When I went in the cab and tried giving it some gas there was an electronic clicking noise from in the cab when I touch the throttle, I discovered if I turned on LSD I could give it throttle without hearing that electronic noise. So now I'm wondering if this sound is coming from the rear differential, which I just changed the fluid in not too long ago, I changed the fluid after I started hearing the sound, I didn't see any big metal shavings or anything alarming in the fluid. Or I'm wondering if the sound is coming from the axle bearings. I'm not very mechanically inclined so I don't know how to go forward checking these things to eliminate what the sound might be. I also did notice while in the cab applying some throttle a wobbling that felt like a miss balanced tire however I don't think tire balance was the case because the wobbling was also intermittent It did it for a little while and then stopped. I've tried recording this sound to attach a file but you can't hear it in my phone when I've recorded while driving so I did not attach it.