My car started making this noise a few months ago when I had it in gear and when I had the brakes on. putting it in neutral or park stopped the noise, but it gradually creeped into that as well. My friend was kind enough to crawl under my car and replace the starter (had several dead spots on the armature) and try to tighten the TC bolts but found one that was slightly less impossible to turn than the other two.

It still makes this noise.

It does not make this noise when I'm moving faster than ~10mph or so, just when I'm going slowly. It's not loud, but it's louder when in reverse, depending on where you're standing in relation to the car, you can't hear it, I only here it when I'm parked against a wall or something.

I don't think it's the transmission or the engine because my guess is that it'd get worse the faster the engine ran.