I have a small whine sound that almost sounds like a bearing or vacuum noise when I switch to 4 wheel high and low. I often use 4 wheel drive and have never heard this sound before. When switching to 2 wheel high (from the dash control) it continues for a bit until I get over 30mph and then it goes away. Thinking it might be the vacuum (shift on the fly from the console) I then turned the hubs (left the dash control on 2 wheel mode). It still does it, but when I turn the hubs back to 2 wheel position it immediately goes away. Everything functions normal, just concerned about that whirring/whine noise. It doesn't sound like any gear related sound. Any takers on a probable cause. Only have 22K and may have the dealer take a ride along...

Thanks for any input.

 

Is it a low or high pitch whine? All of my previous (3) F-150's and current F-250 all had a different tone when 4x4 is engaged. The sound (to me) has/is coming from the gears for the front wheel drive.

 

my 04 f150 has a whistle in 4lo but not in 4hi, same with my boss' f250. i've never had any problems with either and their in 4 wheel drive weekly

 

It's a high pitched whine/squeal. It just started doing it. As mentioned I use 4 wheel drive quite a bit and haven't really heard (or at least paid attention to) this noise before....seems near the transfer case, but not sure