2007 Suburban LT - Weird noise when flooring it

As previouslty mentioned, the BURB does run like a champ now since she came back from the dealer. One weird thing I noticed however today, while "flooring" the truck and really make her go like a bat out of hell, at the higher RPM's just before you left off of the gas or she upshifts, there is a weird sound that I can only describe as:

- Loud Wind Howl
- Louder whistel sound
- Burning/Squeeling tires

(and I do not recall ever noticing it before, as I did not ever floor it prior in the couple of days I had her before taking her to the dealer for the check up).

Now is it possible that when I hit her hard and she downshifts and goes, that the tires could spin due to the truck being completely empty with no weight in the back and this being the strange whistle/hauling?

There is no strange engine noise, truck performs and shifts as it should, no warning lights are coming on, ........................ I NEVER hear any of this when I drive her "normally", in the lower RPM range.

I called the dealer and asked what they thought, they can not make any heads or tails out of it either and asked me to bring it in and have them take a look/have a "hear".

Any thoughts?

Belt slipping or onset of bearing failure on one of the belt driven components(a/c condensor, etc.)?? Or perhaps a vacuum leak somewhere along the intake plenum.

iwaslowr said:

Belt slipping or onset of bearing failure on one of the belt driven components(a/c condensor, etc.)?? Or perhaps a vacuum leak somewhere along the intake plenum.

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+1

+2. My bet is belt

Seeing on how he just had a bunch of work done.....: http://www.tahoeyukonforum.com/forum/showpost.php?p=468774&postcount=69

I was gonna say belt as well but it was replaced according to J. I'd say a vacuum leak of some kind--you would probably not notice it under light to moderate acceleration but it is enhanced under WOT. With all the stuff he had done, I wouldn't doubt if something was accidentally knocked off

JZ BLK 06' said:

Seeing on how he just had a bunch of work done.....: http://www.tahoeyukonforum.com/forum/showpost.php?p=468774&postcount=69

I was gonna say belt as well but it was replaced according to J. I'd say a vacuum leak of some kind--you would probably not notice it under light to moderate acceleration but it is enhanced under WOT. With all the stuff he had done, I wouldn't doubt if something was accidentally knocked off

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Thanks Guys. I hope it is only a vaccum leak.

YES, BOTH BELTS A/C and SERPENTINE have been changed.

It is DEFINITELY NOT noticeable during light, moderate acceleration.

Didn't you just have a Magnaflow installed? Check the welds, I bet there is a spot that they blew thru the exhaust pipe and thats what is whistling.

InTruckDesign said:

Didn't you just have a Magnaflow installed? Check the welds, I bet there is a spot that they blew thru the exhaust pipe and thats what is whistling.

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VERY GOOD POINT, thanks. But would I not hear that also at low RPMS?

Also when stepping on it in PARK or NEUTRAL, no signs of this sound at all.

So, while driving home with the windows down today, I can hear the whistle even when driving the truck moderately.

I am therefore really thinking that there is a problem with the way the MAGNAFLOW was installed and that there is an exhaust leak.

STAY TUNED!!!!!!!!!!!

Problem solved

The Dual Chrome Tip created the whistle sound under heavy load, when the exhaust was serioulsy putting some pressure through there.

Cut the dual tip off and hit her hard, .............. SOUND GONE!

So I put the same straight chrome tip on her as I already have on my NBS Yukon, does not look bad I think?