I just had this same thing in my 2003 gt. Mine was the nut that holds the yoke on in the rear end had loosened off. Hard to tell if its the same noise as yours
1 year post video, I have the same thing going on and trying to research and diagnose it. I did actually change transmission fluid, but I have an automatic. The transmission sounds is very similar. I got the car with 131k miles on it. Did you have to replace your transmission or what was your fix?
I ended up selling the car but the fix wouldve been to replace or rebuild the trans. If your automatic is whining and the whine gets louder with more rpm then the torque coverter or pump is going out in the transmission. The trans might still last a while even with the whine. I had a 96 blazer and the auto whined pretty good for the 5 years and 50k miles i owned it. The sound never got any worse and it was still shifting good when i sold that truck
