Mooing sound

Does anyone hear an occasional mooing sound that comes from the rear side of the Venture?  This happens sometimes on low speed during or after braking.
 
thanks
 

uuuhhh.....no

Yes, I hear that on my 2002 venture.  I was told by GM it was from the airconditoner which they replaced during the warranty period.  I still hear the mooing occassionaly but since its not that often it doesnt bother me.  I dont notice it after braking but it usually occurs in low speed or after idling.