Took my 2500HD in today to have the service department look into an occasional regen exhaust smell that fills the cab while sitting at a light. I found a TSB on the Duramax Diesel forum a couple of weeks ago that has Chevrolet correct this problem. The problem seems to be the alignment of the down tube from the turbocharger. They looked at it, might have tried to realign it and found that they need to replace that part of the exhaust. Needless to say, parts on order. Has anybody else with an 07-08 Duramax had this issue?!?