2003 Chevy Avalanche Drivetrain Rattle

2003 CHEVROLET AVALANCHE
99,500 MILES • V8 • 4WD • AUTOMATIC
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KRASHFREEWAY
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I have a 2003 Z71 Avalanche with 99,500 miles on it. Just recently, I very metallic rattle coming from below the truck while driving. It was a low frequency at low speeds, and increased in frequency until about 25mph, and then went away. I figured it was a heat shield that broke loose, so I looked underneath and everything seems secure. The noise is not made if the truck is being revved in park...only while driving - I think that rules out the cat/exhaust. It happens in 2WD & 4WD. Any body have a similar issue?
Feb 26, 2009 at 4:36 PM
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JACOBANDNICKOLAS
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Have you taken a rubber mallot to the exhaust?
Mar 23, 2009 at 5:01 PM
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KRASHFREEWAY
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You think its the cat? I though about it but haven;t done anything about it yet. I did find out that my u-joint's trashed though
Mar 25, 2009 at 2:46 PM
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JACOBANDNICKOLAS
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Hi:
If the u-joints are bad, I would start with them. They could cause that noise. As far as the converter, sometimes the guts in the converter break loose and rattle. Not only is it a pain, it can cause engine trouble.

Let me know about the u-joints. If they are that bad, chances are that is the problem.

Joe
Mar 25, 2009 at 8:48 PM