Well, in reference to the turbo cool down sound, I hear it everytime I cut the truck off...regardless. I have one of the Turbo Saver's for the new 6.0L Diesel from ShopDiesel.com and I usually let it idle for 2-3 minutes before it cuts itself off, and even then, it's like a burst of air goes out of the tailpipe which I assume is the noise we're all talking about. I'm not too worried about it, because it's done it since day one.

Basically for those of you who don't know what a Turbo Saver is, it's a device that plugs into the truck's wiring harness and allows somewhat of an ignition override when you turn the key off after pushing a button to activate it...it has a timer and will allow you to remove the key from the ignition, lock the door, etc without having to worry about someone stealing the vehicle while it's still running. The safety feature, when you press on the brake, automatically cuts the truck off. Also, there is a toggle switch that allows you to keep the truck from starting, even if you have the key. Very useful, and maybe something you might be interested in.

 

I can hear my turbo winding down when I jump out of the truck quickly after shutting off the vehicle. It only winds for about 3-5 seconds if that long.