I have a 2000 Ford 7.3 Powerstroke and it has a huge squeaking problem. It sounds like it's something to do with the belt. But it is very annoying and sounds super bad.

Any ideas on what this could be? Thanks.

 

I found that cheaper belts will squeak after a short period. Tried one from Napa & Advance, both were noisy within a month. Installed the best quality Gates belt that Napa carried & it's been quiet for over two years.
I even changed the three belt tensioners thinking it may have been them making the noise.
The old tensioners and belt went into the toolbox just in case.

 

Try taking a soap bar and putting on the grove of belt while running. If squeak stops you need a belt. Also check tension pulleys. They Will sound horrible when they go bad. Just pull the belt off and turn by hand if it's tight or makes any sounds then time to replace. As a rule of thumb I always replace tension pulley every time I replace the belt.