Hello, Recentley my 2001 2500HD 6.0 started making a wierd whine on cold mornings. Once I get going down the road it will whine. Any gear usually less than 40 MPH but sometimes around 55 MPH it will come on quick than go away. Happens only when its cold and when i put the truck into neutral the sound remains. Dealer ship said it is normal pump whine from the trans. Repair shop said it was something in drive train but doesn't know for sure. Can someone please give me some direction. Thank you in advance.