I just bought an 2007 Quadcab 2500 4x4 with the 6.7 engine non blue-tec. The truck has the engine brake on it, the thing is when I have it turned on and is active there is a whistling coming from the turbo. I have been around Diesel engines all my life and never heard anything like this. I talked to one of the guys back at the dealership and he said his 08 did the same thing, but I guess I would like to hear it from a few more guys before I stopped worring about it. Thanks for anything help

 

My 5.9 sounds like like a jet when its idling. The whisteling sound is normal , mine does it too. Your basically your capping of your exhaust so you can imgine what the sound would be if you put your hand over the tailpipe.

 

its completly normal, it creates more pressure which helps wind up your turbo