My 6.0 is making a weird scuffing sound when I let off the gas and after it shifts. If I drive easy it doesn't seem to happen. But if I have to accelerate fast it will make the sound inbetween shifts and if I let off the gas real fast it will make the sound. It only lasts for about 3 seconds or so. It sounds like its possibly in the exhaust. Anyone else experience this?

 

Check ur boots, check all turbo connections. Make sure everything is seated in and sealed especially around clamps. Also check ur belt. It may even be the belt. Weird but then again, we drive six-ohs. Welcome to weirdness. Lol.

 

Your describing what is commonly referred to as a "turbo fart". Sort of a chuffing air sound that often has the rhythm of a ball bouncing three or four times. It's not uncommon on these trucks and if you lift the throttle quickly it will do it every time. On the other hand in normal driving it shouldn't happen all that much and a sticking turbo can make it happen easier.

 

Does it sound like this: