Not sure if this is normal, but I've developed this turbo "whine" from my truck. I'm pretty sure its coming from the turbo or related parts, because when I let off the throttle, that's when it makes the noise. The harder I press on the throttle and let go, the louder the whine is. Is this normal? What is the noise? Good, bad?

is it kind of like a howl or groan? I noticed mine does that since I put the 5 inch exhaust. depending on the tune i'm running depends how loud it is. I thought it was just the way the vanes moved.

It is just the turbo, normal.

I am referring to a whine, not whistle. I never noticed it before, so its like a developed noise. Why didn't it do it from the beginning? What causes this noise?

Might want to take it to the dealer, let them look at it.

So then this white I speak of is NOT normal? I've always heard the whistle since I got the truck and even more so when I installed the exhaust. It only happens when I let off the accelerator pedal. The harder I get on it and let off, the louder it is.

Yes, you could also describe it as a groan or growl.

I never noticed this noise from when I first purchased the truck. It only has 17k miles on it. Even when I installed my exhaust which includes a cat and muffler delete, I still didn't hear anything.

I don't think its a noise that was there and I didn't notice, its a noise that has developed. I'm just curious if anyone else has this noise.

After I accelerate letting off the pedal, I only used to hear the turbo whistling down. Now I'm getting a howling sound.

Might want to take it to the dealer, let them look at it.

Mine is straight piped 4", and when i get on it pretty good then let off it has this kind of blow off whine sound to it. I was told it was normal. I'm not getting any problems with it or anything. But yeah the dealer might be a good thing to go see.

Not sure if this is normal, but I've developed this turbo "whine" from my truck. I'm pretty sure its coming from the turbo or related parts, because when I let off the throttle, that's when it makes the noise. The harder I press on the throttle and let go, the louder the whine is. Is this normal? What is the noise? Good, bad?
Its totally normal, its the turbo blow off valve, my 05 did it and my LMM does it now that it is straight piped, I think it sounds fricken cool....I found this explanation of how it works for clarification.....

A blow off valve goes under many different names such as dump, bypass, recirc (short for recirculation), diverter, and pop off valves. No one term is correct, the lingo just tends to change in different regions and countries. Basically these valves are all designed to the same job, and we will refer to all types as blow-off valves to save confusion.
What it does: The only job a blow-off valve is supposed to perform is to relieve excess turbo pressure that results from shutting the throttle rapidly under boost conditions. This then answers one of the questions we get asked a lot – yes you need a turbo to fit a blow-off valve! Otherwise you will have a rather expensive paper-weight. It is necessary to release this pressure because it will try to find a way out of the system, and the only way is back out through the turbo. This produces a fluttering noise as the air passes backwards through the turbo, which is often unwanted. There is also a school of thought that a blow-off valve can improve turbocharger longevity or, in extreme cases, prevent damage to the turbo.

Our trucks don't have a blow off valve. My truck make the same sound. I figure it must be normal.

your truck has a waste gate... same thing as a blow off valve

your truck has a waste gate... same thing as a blow off valve

Actually it doesn't, only the LB7's do. The LLY and LBZ don't have anything.

yea lly and lbz are electronically controlled no wastegate. Also a wastegate is different thatn a blow off valve. Do a search and should be able to find the explanation for the difference pretty easily

I know this sounds odd but I had a whine last week and my power steering pump was low. It did the same thing you say. It whined louder the more throttle you gave it. Just a suggesetion.