why does my car make a siren sound when accelerating?

After I start my car and it warms up when I accelarete my engine makes a siren sound. It does this when I accelerate to 20mph or more once I get past 45 mph it seems to quite but is still noticable. My transmission fluid level is full but seems to not be the right color (is a lighter color and smells a bit burned). The siren sound is coming from the middle front side of my engine compartment.