Buzz/rattle while accelerating

[ezegoin]

Guys, Here's the problem I'm having w/ my 02 TB and it's driving me nuts. I have what sounds like metal on metal vibration while "lightly" accelerating (front undercarriage). It sometimes occurs while driving at highway speed (not very often). If I punch the accelerator I don't get the noise. I've tried the usual suspects listed in the forum (hood latch, even went so far as to take it off completely) and I still get the noise. I've removed the hood prop entirely, still get the noise. I even checked the transmission cooling lines and placed rubber tubing to give it some cushion where the two lines were close, still got the noise. I'm at a loss as to what it could be now. I did find the following TSB off the NHTSA site but can't find the fix on alldata or anywhere else.

Make: CHEVROLET
Model: TRAILBLAZER
Year: 2002
Manufacturer: GENERAL MOTORS CORP.
Service Bulletin Num: 120902
Date of Bulletin: DEC 09, 2002
NHTSA Item Number: 10002739
Component: STRUCTURE:BODY
Summary:
BUZZ OR RATTLE NOISE COMING FROM THE FRONT END OF LIGHT ACCELREATION AT 25 TO 45 MILES PER HOUR OR OVER BUMPS. *TT

I saw a bunch of posts regarding the swaybar links making noises, is that a metal on metal vibration noise? I'd rather not start throwing money at this and not get the issue fixed.

Any help on this would be greatly appreciated.

[hoezaycuervo]

Not sure if you checked but exhaust systems can rattle if they become loose, the sway bar endlinks could also be the culprit, though they tend to squeak instead of vibrate.

[ezegoin]

I've checked the exhaust by tapping it w/ a rubber mallot, everything seems tight. I was thinking it might be the heat shield over the exhaust but that seems tight also and from where the noise seems to be coming from it doesn't appear to be an contact with anything else (other than where it attaches).

[Briandog1]

I have it too and just ignore it. If you go to ALLDATA I think you can find a TSB for it

[ezegoin]

The TSB that I need is not listed on alldata's site. It does show up on the NHTSA site.

"buzz or rattle noise coming from the front end of light accelration..."

I was able to ignore it for a while but now it's become a mission of sorts. I know it's going to be something stupid too.

[tblazed]

Mine had a similar buzz-rattle at certain rpm and load when I first got it turned out was a heat shield on the trans itself, btwn the trans and the cat converter. One corner was just barely toughing the trans case. Bent it out a bit and no more noise. Another rattle was from an electrical connector to the trans touching against the bottom of the floor under the hump, would rattle against the floor while sitting stopped idling. Fixed both myself saving GM warranty expense and myself aggravation with the dealer.

[ezegoin]

Thanks, I'll doublecheck all of the heat shields again.

[muddy tires]

Had a similar annoyance that turned out to be a loose bolt on the brush guard.

[ezegoin]

I want to thank everyone for the help on this issue. I came up with a fix. We traded in the TB for an 06 Envoy. Although it is an expensive fix, the wife is happier and no more noise. :)

Thanks again.

[APDMC6008]

Did the dealer see you coming? :p

FWIW to all those who are reading it and expecting to see what the possible source and the fix for the noise is... mine had a rattle, and it was the heat shield by the catalytic converter and the tranny. Someone else above also stated they had the same issue.

[kstornado]

Thanks for the replies...I have had the same problem for a while now. Sounds like it's exhaust related, so I'm gonna crawl underneath this weekend and have a look at the heat shields....