Engine Whistle Ram 1500 2001 4X4

I live in the NWT and only in the winter does my truck make this slow whistle sound. I warm it up for at least 15 minutes before drive, I bought a winter front...and still I get greeted with this whistle. It doesn't happen at high speeds. What can I do??

its just air being sucked into the intake

Check and make sure the air intake snorkel is properly fastened to the throttle body. They will whistle if it isn't fully seated on the fiber gasket on top of the throttle body.
You may also require a good throttle body cleaning. Excessive carbon build up around the throttle blade and AIS passage can create a whistle also.

My truck did that when it was really cold out. I think it was just the idler or one of the other pulleys on the belt path that did that from the bitter cold. It would stop doing that once you got going and everything warmed up though...

I noticed that with mine too, and although i am running a diesel, there was something other than a turbo whistle when cold. Turns out there was a flow restrictor in the heater line, which produces a whistling sound in colder temps. go figure. I don;t get it. But, thats ok, great trucks, wouldn't have any other. I live in the Yukon, so we run in close to the same conditions.