I have a 2006 V6 Mustang with around 79K miles on it. I got it about a year ago, and at around 1500 RPM a drone/rumbling noise occurs. I can hit it on the spot every time I choose, at 1500 RPM, and I can hold it there to cause the rumble. The second I step off of the gas, the drone stops, same thing goes if I speed up. The car is completely stock, other than an aftermarket radio and a trunk release button inside the car. I looked up the TSB and the issue that was described sounded like mine, but upon further inspection, what they described, with a hanger being loose, was not the case on mine. The TSB sheet states that the hanger could still be causing it by throwing vibrations up through the transmission and that it can be removed. If I remove the hanger, I cant put it back on, as it has to be cut off. Should I remove the hanger? What else could be causing this? Its not just a noise, you can actually feel the rumble as well.

Help would be appreciated.