Squeaking noise

I have a 1998 F-150 and I have a squeaking noise and I can only hear it when I am in in first gear at low speed and when I'm in reverse backing up and goes away when I press the clutch pedal. I'm thinking its either my U-Joints or Throwout bearing. Any ideas on what it could be?

My guess is the exhaust heat shield by the catalytic converter. They can break loose and only make noise when in slow speed driving conditions.

And I forgot to mention this in the question/problem but the squeak goes along with the wheel speed.

I think you may be onto something with the throwout bearing idea. Also maybe your clutch disc is worn and its slipping just a little bit. Not enough to be noticeable through the power output, but just enough to make a little bit of noise.