Could be something as simple as a brake shoe dragging a bit... Does it go away while braking (but still in motion)? When was the last time the shoes were changed? Might just need to back off the star wheel on the rear drums a bit, or could be due for a replacement.

Could also be a bearing is beginning to ask for some more grease. (Though we usually don't notice bearings until they're more high pitched.)

I halfway agree with dhvaughan above: get the rear off the ground, but try spinning entires by hand before you start it up. See if you can track it down that way first.

 

I had the rear off the ground and listened, I couldn't hear any distinct sound like I hear when I pass anything that echos sound, I listened by both tires, and couldn't hear a thing lol, the rear drum brakes were changed out in February when I had a wheel cylinder bust and was losing brake fluid fast, took that time to change out both of the wheel cylinders and both sides of the brakes.

I took the drivers side rear tire off and had my friend engage/disengage at different intervals both the e-brake and the regular brake and everything seemed fine there, I didn't take passenger off yet, as the sound mainly seemed to come from the left side of the truck.

 

Okay it definitely has to be a problem with my drum brakes, I've noticed sometimeS I hear a light click from my drum brakes then I can hear the noise when I drive by something that echoes, but if I stop and apply the ebrake and release it it goes away, so maybe the brake shoes are too close to the drum wall, how can I try and adjust them?

 

The shoes should *just* be rubbing the drums in any event. Actually, you probably have them adjusted right..... where they weren't before.

 

So they rub it enough where I hear that god awful low pitched hiss? It seems I hear the click quite a bit and then get the noise? Can adjusting the star thing a notch or two hurt the braking? I never before had issues braking and still don't but never heard that annoying hiss either until about a week or so ago?

 

What does it mean when I can barely turn the passenger side wheel when in neutral and can't turn it at all in neutral with the wheel off?

 

Rear brake adjustment controls pedal height. That's about it. You can safely back them off some, just have to push the pedal a little further before they start doing anything.

Passenger side is too tight. Need to push the adjuster arm away from the star wheel, and then back it off a bit. If you don't move the adjuster arm out of the way, you won't be able to back off the adjuster.

That may be your noise.

 

Passenger side definitely too tight. That click is probably the star wheel self-adjusting.

Did you get all 47 springs (or however many there are ) back in the right place and in the right order? Were any of them worn and needing replacing? I personally replace all the springs when I do the rears- makes them a real PITA to get back on sometimes, but I know everything will be nice and tight and not sagging out of place.

One other thought, if the passenger side has been dragging since February, it may have enough wear that they may need replaced again. Make sure they're not too far out of round.