Hello all! First time post.
I joined about a month ago and have enjoyed reading & getting a lot of helpful tips on here. But now I've come across something I cannot figure out.

I have a 2000 F150 XLT, 5.4L, 4x4, automatic with about 183K miles on it. I've only owned the truck for about 3 months and so far, it's been a great truck but I know nothing about it's history, service intervals, etc.

A few days ago, I noticed a noise when ever I would stop at a red light. It goes away, or seems to go away when I let off the brake and accelerate. It also goes away when I am in park or neutral. Drive, 1st or 2nd with my foot on the brake and the noise comes back. It almost sounds like a pulley noise or something spinning. It is hard to tell where it is being generated from. Nothing looks out of place or loose underneath and there are no signs of leaks. The sound is not terribly loud, yet anyway. So far, it shifts fine & drives fine. Transmission fluid level is just above max. I tried uploading a clip but I'm not sure if it loaded. I'll try again if it didn't post.
Transmission or torque converter issue? Any ideas would be appreciated.