squeeching sound coming from rear wheels

Ok I need some help. I rotated my tires last week to provide additional info. No noise until yesterday. I was driving home in a huge storm. My truck was doused with water. Like almost submegered at one point. I noticed a ticking noise after that when I was cruising without throttle. With throttle it would dissapear. When I pulled in my driveway there was a horrible screeching noise coming from the drivers side rear. I got out and saw nothing unusual. I had my gf slowly pull forward and it did it again.

It doesn't do it in reverse. Any ideas as to what it is? Where to begin checking?

 

Nevermind I fixed it. It was a piece of the metal flashing from the gas tank rubbing on the driveshaft. Somehow one of the plastic buttons came out and it got bent back.