Help with noise

My blazer has been makin a funny noise in the rear end. Its been going on ever since i got it. At low speed you can hear a repititious sound like a wawawawawawawa an it only gets faster when speed increases. My dad thinks it might be in the axle or transfer case, but ive talked with my shopteacher an he says its tires. The tires are getting close to when they need to be replaced. Any help?

If there is a vibration as well at higher speeds you could have seperated a belt in the tire

How do you brakes look you may have warrped or worn out rear rotor if you have rotors or a damaged drum in the case of drums.

I had my Auto mech. teacher ride along an listen to the noise hes been in the auto business for 20+ years an he says its tires, so im hoping once i get new tires that the noise will go away, ill just have tread noise.

is it more of a squeaking noise because if that is the case it would most likely be a u-joint

Not a squeking noise.

I'd say universal joint. Just for kicks I would take off the rear diff cover and inspect the gears, also check the backlash of the ring gear in relation to the pinion. A crappy inner bearing may cause this tolerance to be out. Good Luck.