Transmission making rattling, spinning noise

2000 GMC SIERRA
294,000 MILES • 4.8L • V8 • 4WD • AUTOMATIC
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BOBSONLY
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I believe that my transmission is making a rattling, spinning noise underneath from a complete stop, like metal on metal, to a higher RPM then seems to fade out on the noise. In reverse it sounds like a 'snick' metal noise when the transmission is engaged. Scratching my head at this one. Help is appreciated. Transmission was overhauled a year ago.
Jun 16, 2018 at 7:14 AM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,837 POSTS
  • ASE Certified Mechanic
Hello,

If you can take a quick video of the noise and upload it in your response we can tell for sure, but it sounds like you have a cracked flex-plate or a catalytic converter that has fallen apart.

Here is are videos to help you see what you are in for when changing the flex plate or catalytic converters.

https://youtu.be/CORe9JyrexI

and

https://youtu.be/3vJAojsrfuU

Please let us know what you find.

Cheers, Ken
Jun 18, 2018 at 11:23 AM
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