Just started getting a major squeal from what sounds like the left rear wheel. As I give gas from a stopped position, it grows in intensity and gets faster, so obviously has something to do with the wheel rotating. Once you get up to about 20 mph, it is high pitched enough that you can't hear it very well, but at lower speeds it is very loud. Taking your foot off the gas causes the sound to instantly go away. No sound during braking or in reverse.

Any ideas?

 

sounds like you have your pads worn down to the "noise makers" or wear tabs rather.
Have you taken a look at your pads lately?

 

That would be my first though also, brakes.

 

it was mine too but he said NO sound when braking which is when you should get most of your noise. but you never know.

 

axle shaft bearing, pads worn down, rotors warped/rusty.
i would look at the pads as well. inboard and outboard pads

 

my dads jeep had the same problem it was something in the diff but i cant remember what it was