unusual noise

I've been noticing an unusual noise coming from my truck. It occurs when I first start out in the mornings. I back out of the driveway and when I drop it into drive and start to pull out, I hear this noise that sounds similar to air being let out of an air break. It lasts about a sec or so, kinds like shshssssss. Any idea what it could be? I've only noticed it when the weather has gotten colder.

Thanks

 

I have the same noise.. ppl made fun of me when I described it.. I don't know what it's caused by..

it's like a PEWWSSHOOEEEE

 

sounds like the abs modulator

 

So it is something I, we, should be concerned with? Thanks

 

if it is the abs modulator,its just the pump priming the abs system.....which is normal

 

dealer said this was normal, abs pump activating its kinda embarassing when you friends in truck with you

 

Sounds like your neighbors cat, the noise is that he is pissed bc you caught his nuts in a fan belt.

But on a serious note, hope y'all figure it out!