When shifting gears at higher rpms like approaching a freeway ramp a strange noise comes from under the hood. Sounds as though it is coming from the turbo. Is this just the turbo spooling ? Seems to happen more frequently when pulling my fifth wheel. I have a 6 speed g56 with a new south bend clutch maybe 5k on the clutch I believe that the clutch is not the problem because the problem noise was there before the new clutch and the sound is from under the hood right front.

 

The turbo always spooled- if this is a new noise, it is safer to assume that something has changed, than it is to assume that nothing has. I would pull be looking at the turbo since it is high dollar and under tremendous loads, and then go from there. New noises happen for a reason. Always explore them.